diff --git a/docs/persistence/sql/expressions.rst b/docs/persistence/sql/expressions.rst
index 680c182ff..2a6f91bca 100644
--- a/docs/persistence/sql/expressions.rst
+++ b/docs/persistence/sql/expressions.rst
@@ -299,21 +299,6 @@ parts of the query. You must not call them in normal circumstances.
       $query->consume('first_name');  // `first_name`
       $query->consume($other_query);  // will merge parameters and return string
 
-.. php:method:: escape($value)
-
-  Creates new expression where $value appears escaped. Use this method as a
-  conventional means of specifying arguments when you think they might have
-  a nasty back-ticks or commas in the field names. I generally **discourage**
-  you from using this method. Example use would be::
-
-      $query->field('foo, bar');  // escapes and adds 2 fields to the query
-      $query->field($query->escape('foo, bar')); // adds field `foo, bar` to the query
-      $query->field(['foo, bar']);  // adds single field `foo, bar`
-
-      $query->order('foo desc');  // escapes and add `foo` desc to the query
-      $query->field($query->escape('foo desc')); // adds field `foo desc` to the query
-      $query->field(['foo desc']); // adds `foo` desc anyway
-
 .. php:method:: escapeIdentifier($sql_code)
 
   Always surrounds `$sql code` with back-ticks.
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 3952d4cea..cc78f8240 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -14,7 +14,8 @@
     </listeners>
     <coverage>
         <include>
-            <directory suffix=".php">src</directory>
+            <directory>src</directory>
+            <directory>tests</directory>
         </include>
         <report>
             <php outputFile="coverage/phpunit.cov" />
diff --git a/src/Persistence/Sql.php b/src/Persistence/Sql.php
index 68a76c769..81d9f6931 100644
--- a/src/Persistence/Sql.php
+++ b/src/Persistence/Sql.php
@@ -168,28 +168,23 @@ protected function initPersistence(Model $model): void
 
     /**
      * Creates new Expression object from expression string.
-     *
-     * @param mixed $expr
      */
-    public function expr(Model $model, $expr, array $args = []): Expression
+    public function expr(Model $model, string $template, array $arguments = []): Expression
     {
-        if (!is_string($expr)) {
-            return $this->getConnection()->expr($expr, $args);
-        }
         preg_replace_callback(
             '~\[\w*\]|\{\w*\}~',
-            function ($matches) use (&$args, $model) {
+            function ($matches) use ($model, &$arguments) {
                 $identifier = substr($matches[0], 1, -1);
-                if ($identifier && !isset($args[$identifier])) {
-                    $args[$identifier] = $model->getField($identifier);
+                if ($identifier !== '' && !isset($arguments[$identifier])) {
+                    $arguments[$identifier] = $model->getField($identifier);
                 }
 
                 return $matches[0];
             },
-            $expr
+            $template
         );
 
-        return $this->getConnection()->expr($expr, $args);
+        return $this->getConnection()->expr($template, $arguments);
     }
 
     /**
diff --git a/src/Persistence/Sql/Connection.php b/src/Persistence/Sql/Connection.php
index 9f27a69cb..2413f0e5c 100644
--- a/src/Persistence/Sql/Connection.php
+++ b/src/Persistence/Sql/Connection.php
@@ -298,9 +298,8 @@ public function dsql($properties = []): Query
      * Returns Expression object with connection already set.
      *
      * @param string|array $properties
-     * @param array        $arguments
      */
-    public function expr($properties = [], $arguments = null): Expression
+    public function expr($properties = [], array $arguments = []): Expression
     {
         $c = $this->expression_class;
         $e = new $c($properties, $arguments);
diff --git a/src/Persistence/Sql/Expression.php b/src/Persistence/Sql/Expression.php
index d7ae151d8..12de95f59 100644
--- a/src/Persistence/Sql/Expression.php
+++ b/src/Persistence/Sql/Expression.php
@@ -11,6 +11,7 @@
 use Doctrine\DBAL\ParameterType;
 use Doctrine\DBAL\Platforms\OraclePlatform;
 use Doctrine\DBAL\Platforms\PostgreSQLPlatform;
+use Doctrine\DBAL\Platforms\SqlitePlatform;
 use Doctrine\DBAL\Platforms\SQLServerPlatform;
 use Doctrine\DBAL\Result as DbalResult;
 
@@ -74,39 +75,18 @@ class Expression implements Expressionable, \ArrayAccess
      * If $properties is passed as string, then it's treated as template.
      *
      * @param string|array $properties
-     * @param array        $arguments
      */
-    public function __construct($properties = [], $arguments = null)
+    public function __construct($properties = [], array $arguments = [])
     {
-        // save template
         if (is_string($properties)) {
             $properties = ['template' => $properties];
-        } elseif (!is_array($properties)) {
-            throw (new Exception('Incorrect use of Expression constructor'))
-                ->addMoreInfo('properties', $properties)
-                ->addMoreInfo('arguments', $arguments);
         }
 
-        // supports passing template as property value without key 'template'
-        if (isset($properties[0])) {
-            $properties['template'] = $properties[0];
-            unset($properties[0]);
-        }
-
-        // save arguments
-        if ($arguments !== null) {
-            if (!is_array($arguments)) {
-                throw (new Exception('Expression arguments must be an array'))
-                    ->addMoreInfo('properties', $properties)
-                    ->addMoreInfo('arguments', $arguments);
-            }
-            $this->args['custom'] = $arguments;
-        }
-
-        // deal with remaining properties
         foreach ($properties as $key => $val) {
             $this->{$key} = $val;
         }
+
+        $this->args['custom'] = $arguments;
     }
 
     /**
@@ -170,28 +150,10 @@ public function offsetUnset($offset): void
      * new expression to the same connection as the parent.
      *
      * @param string|array $properties
-     * @param array        $arguments
-     *
-     * @return Expression
      */
-    public function expr($properties = [], $arguments = null)
+    public function expr($properties = [], array $arguments = []): self
     {
-        if ($this->connection !== null) {
-            // TODO condition above always satisfied when connection is set - adjust tests,
-            // so connection is always set and remove the code below
-            return $this->connection->expr($properties, $arguments);
-        }
-
-        // make a smart guess :) when connection is not set
-        if ($this instanceof Query) {
-            $e = new self($properties, $arguments);
-        } else {
-            $e = new static($properties, $arguments);
-        }
-
-        $e->identifierEscapeChar = $this->identifierEscapeChar;
-
-        return $e;
+        return $this->connection->expr($properties, $arguments);
     }
 
     /**
@@ -281,21 +243,6 @@ protected function consume($expr, string $escapeMode = self::ESCAPE_PARAM)
         return $sql;
     }
 
-    /**
-     * Creates new expression where $value appears escaped. Use this
-     * method as a conventional means of specifying arguments when you
-     * think they might have a nasty back-ticks or commas in the field
-     * names.
-     *
-     * @param string $value
-     *
-     * @return Expression
-     */
-    public function escape($value)
-    {
-        return $this->expr('{}', [$value]);
-    }
-
     /**
      * Converts value into parameter and returns reference. Use only during
      * query rendering. Consider using `consume()` instead, which will
@@ -315,7 +262,72 @@ protected function escapeParam($value): string
     }
 
     /**
-     * Escapes argument by adding backticks around it.
+     * This method should be used only when string value cannot be bound.
+     */
+    protected function escapeStringLiteral(string $value): string
+    {
+        $platform = $this->connection->getDatabasePlatform();
+        if ($platform instanceof PostgreSQLPlatform || $platform instanceof SQLServerPlatform) {
+            $dummyPersistence = new Persistence\Sql($this->connection);
+            if (\Closure::bind(fn () => $dummyPersistence->binaryTypeValueIsEncoded($value), null, Persistence\Sql::class)()) {
+                $value = \Closure::bind(fn () => $dummyPersistence->binaryTypeValueDecode($value), null, Persistence\Sql::class)();
+
+                if ($platform instanceof PostgreSQLPlatform) {
+                    return 'decode(\'' . bin2hex($value) . '\', \'hex\')';
+                }
+
+                return 'CONVERT(VARBINARY(MAX), \'' . bin2hex($value) . '\', 2)';
+            }
+        }
+
+        $parts = [];
+        foreach (explode("\0", $value) as $i => $v) {
+            if ($i > 0) {
+                if ($platform instanceof PostgreSQLPlatform) {
+                    // will raise SQL error, PostgreSQL does not support \0 character
+                    $parts[] = 'convert_from(decode(\'00\', \'hex\'), \'UTF8\')';
+                } elseif ($platform instanceof SQLServerPlatform) {
+                    $parts[] = 'NCHAR(0)';
+                } elseif ($platform instanceof OraclePlatform) {
+                    $parts[] = 'CHR(0)';
+                } else {
+                    $parts[] = 'x\'00\'';
+                }
+            }
+
+            if ($v !== '') {
+                $parts[] = '\'' . str_replace('\'', '\'\'', $v) . '\'';
+            }
+        }
+        if ($parts === []) {
+            $parts = ['\'\''];
+        }
+
+        $buildConcatSqlFx = function (array $parts) use (&$buildConcatSqlFx, $platform): string {
+            if (count($parts) > 1) {
+                $partsLeft = array_slice($parts, 0, intdiv(count($parts), 2));
+                $partsRight = array_slice($parts, count($partsLeft));
+
+                $sqlLeft = $buildConcatSqlFx($partsLeft);
+                if ($platform instanceof SQLServerPlatform && count($partsLeft) === 1) {
+                    $sqlLeft = 'CAST(' . $sqlLeft . ' AS NVARCHAR(MAX))';
+                }
+
+                return ($platform instanceof SqlitePlatform ? '(' : 'CONCAT(')
+                    . $sqlLeft
+                    . ($platform instanceof SqlitePlatform ? ' || ' : ', ')
+                    . $buildConcatSqlFx($partsRight)
+                    . ')';
+            }
+
+            return reset($parts);
+        };
+
+        return $buildConcatSqlFx($parts);
+    }
+
+    /**
+     * Escapes identifier from argument.
      * This will allow you to use reserved SQL words as table or field
      * names such as "table" as well as other characters that SQL
      * permits in the identifiers (e.g. spaces or equation signs).
@@ -459,7 +471,7 @@ public function getDebugQuery(): string
             } elseif (is_float($val)) {
                 $replacement = self::castFloatToString($val);
             } elseif (is_string($val)) {
-                $replacement = '\'' . addslashes($val) . '\'';
+                $replacement = '\'' . str_replace('\'', '\'\'', $val) . '\'';
             } else {
                 continue;
             }
@@ -585,8 +597,7 @@ public function execute(object $connection = null, bool $fromExecuteStatement =
                 } elseif (is_string($val)) {
                     $type = ParameterType::STRING;
 
-                    if ($platform instanceof PostgreSQLPlatform
-                        || $platform instanceof SQLServerPlatform) {
+                    if ($platform instanceof PostgreSQLPlatform || $platform instanceof SQLServerPlatform) {
                         $dummyPersistence = new Persistence\Sql($this->connection);
                         if (\Closure::bind(fn () => $dummyPersistence->binaryTypeValueIsEncoded($val), null, Persistence\Sql::class)()) {
                             $val = \Closure::bind(fn () => $dummyPersistence->binaryTypeValueDecode($val), null, Persistence\Sql::class)();
@@ -689,11 +700,11 @@ private function castGetValue($v): ?string
         }
 
         // for PostgreSQL/Oracle CLOB/BLOB datatypes and PDO driver
-        if (is_resource($v) && get_resource_type($v) === 'stream' && (
-            $this->connection->getDatabasePlatform() instanceof PostgreSQLPlatform
-            || $this->connection->getDatabasePlatform() instanceof OraclePlatform
-        )) {
-            $v = stream_get_contents($v);
+        if (is_resource($v) && get_resource_type($v) === 'stream') {
+            $platform = $this->connection->getDatabasePlatform();
+            if ($platform instanceof PostgreSQLPlatform || $platform instanceof OraclePlatform) {
+                $v = stream_get_contents($v);
+            }
         }
 
         return $v; // throw a type error if not null nor string
diff --git a/src/Persistence/Sql/Mssql/ExpressionTrait.php b/src/Persistence/Sql/Mssql/ExpressionTrait.php
index 31a29b439..066b8e68b 100644
--- a/src/Persistence/Sql/Mssql/ExpressionTrait.php
+++ b/src/Persistence/Sql/Mssql/ExpressionTrait.php
@@ -10,16 +10,20 @@ trait ExpressionTrait
 {
     protected function escapeIdentifier(string $value): string
     {
-        return preg_replace('~\]([^\[\]\'"(){}]*?\])~s', '[$1', parent::escapeIdentifier($value));
+        $res = parent::escapeIdentifier($value);
+
+        return $this->identifierEscapeChar === ']' && str_starts_with($res, ']') && str_ends_with($res, ']')
+            ? '[' . substr($res, 1)
+            : $res;
     }
 
     public function render(): array
     {
         [$sql, $params] = parent::render();
 
-        // convert all SQL strings to NVARCHAR, eg 'text' to N'text'
-        $sql = preg_replace_callback('~N?(\'(?:\'\'|\\\\\'|[^\'])*+\')~s', function ($matches) {
-            return 'N' . $matches[1];
+        // convert all string literals to NVARCHAR, eg. 'text' to N'text'
+        $sql = preg_replace_callback('~N?\'(?:\'\'|\\\\\'|[^\'])*+\'~s', function ($matches) {
+            return (substr($matches[0], 0, 1) === 'N' ? '' : 'N') . $matches[0];
         }, $sql);
 
         return [$sql, $params];
diff --git a/src/Persistence/Sql/Mssql/Query.php b/src/Persistence/Sql/Mssql/Query.php
index 20e5ceb7b..209d97ff4 100644
--- a/src/Persistence/Sql/Mssql/Query.php
+++ b/src/Persistence/Sql/Mssql/Query.php
@@ -54,7 +54,7 @@ public function _render_limit(): ?string
 
     public function groupConcat($field, string $delimiter = ',')
     {
-        return $this->expr('string_agg({}, \'' . $delimiter . '\')', [$field]);
+        return $this->expr('string_agg({}, ' . $this->escapeStringLiteral($delimiter) . ')', [$field]);
     }
 
     public function exists()
diff --git a/src/Persistence/Sql/Mysql/ExpressionTrait.php b/src/Persistence/Sql/Mysql/ExpressionTrait.php
index a72078bdc..6c342c7a8 100644
--- a/src/Persistence/Sql/Mysql/ExpressionTrait.php
+++ b/src/Persistence/Sql/Mysql/ExpressionTrait.php
@@ -6,6 +6,11 @@
 
 trait ExpressionTrait
 {
+    protected function escapeStringLiteral(string $value): string
+    {
+        return str_replace('\\', '\\\\', parent::escapeStringLiteral($value));
+    }
+
     protected function hasNativeNamedParamSupport(): bool
     {
         $dbalConnection = $this->connection->getConnection();
diff --git a/src/Persistence/Sql/Mysql/Query.php b/src/Persistence/Sql/Mysql/Query.php
index 4c3e616b0..c8002cdb9 100644
--- a/src/Persistence/Sql/Mysql/Query.php
+++ b/src/Persistence/Sql/Mysql/Query.php
@@ -20,6 +20,6 @@ class Query extends BaseQuery
 
     public function groupConcat($field, string $delimiter = ',')
     {
-        return $this->expr('group_concat({} separator \'' . str_replace('\'', '\'\'', $delimiter) . '\')', [$field]);
+        return $this->expr('group_concat({} separator ' . $this->escapeStringLiteral($delimiter) . ')', [$field]);
     }
 }
diff --git a/src/Persistence/Sql/Oracle/ExpressionTrait.php b/src/Persistence/Sql/Oracle/ExpressionTrait.php
index e10c85f7a..33cc08e7e 100644
--- a/src/Persistence/Sql/Oracle/ExpressionTrait.php
+++ b/src/Persistence/Sql/Oracle/ExpressionTrait.php
@@ -6,8 +6,51 @@
 
 trait ExpressionTrait
 {
+    /**
+     * Like mb_str_split() function, but split by length in bytes.
+     *
+     * @return array<string>
+     */
+    private function splitLongString(string $value, int $lengthBytes): array
+    {
+        $res = [];
+        $value = array_reverse(str_split($value, 2 * $lengthBytes));
+        $i = count($value) - 1;
+        $buffer = '';
+        while (true) {
+            if (strlen($buffer) <= $lengthBytes && $i >= 0) {
+                $buffer .= array_pop($value);
+                --$i;
+            }
+
+            if (strlen($buffer) <= $lengthBytes) {
+                $res[] = $buffer;
+                $buffer = '';
+
+                break;
+            }
+
+            $l = $lengthBytes;
+            for ($j = 0; $j < 4; ++$j) {
+                $ordNextChar = ord(substr($buffer, $l - $j, 1));
+                if ($ordNextChar < 0x80 || $ordNextChar >= 0xC0) {
+                    $l -= $j;
+
+                    break;
+                }
+            }
+            $res[] = substr($buffer, 0, $l);
+            $buffer = substr($buffer, $l);
+        }
+
+        return $res;
+    }
+
     protected function convertLongStringToClobExpr(string $value): Expression
     {
+        // Oracle (multibyte) string literal is limited to 1332 bytes
+        $parts = $this->splitLongString($value, 1000);
+
         $exprArgs = [];
         $buildConcatExprFx = function (array $parts) use (&$buildConcatExprFx, &$exprArgs): string {
             if (count($parts) > 1) {
@@ -22,18 +65,6 @@ protected function convertLongStringToClobExpr(string $value): Expression
             return 'TO_CLOB([])';
         };
 
-        // Oracle (multibyte) string literal is limited to 1332 bytes
-        $parts = [];
-        foreach (mb_str_split($value, 10_000) ?: [''] as $shorterValue) { // @phpstan-ignore-line https://github.com/phpstan/phpstan/issues/7580
-            $lengthBytes = strlen($shorterValue);
-            $startBytes = 0;
-            do {
-                $part = mb_strcut($shorterValue, $startBytes, 1000);
-                $startBytes += strlen($part);
-                $parts[] = $part;
-            } while ($startBytes < $lengthBytes);
-        }
-
         $expr = $buildConcatExprFx($parts);
 
         return $this->expr($expr, $exprArgs); // @phpstan-ignore-line
diff --git a/src/Persistence/Sql/Oracle/PlatformTrait.php b/src/Persistence/Sql/Oracle/PlatformTrait.php
index e302972a5..696d573b2 100644
--- a/src/Persistence/Sql/Oracle/PlatformTrait.php
+++ b/src/Persistence/Sql/Oracle/PlatformTrait.php
@@ -67,7 +67,7 @@ public function getCreateAutoincrementSql($name, $table, $start = 1)
         $pkSeq = \Closure::bind(fn () => $this->normalizeIdentifier($aiSequenceName), $this, OraclePlatform::class)()->getName();
         $sqls[count($sqls) - 1] = $conn->expr(
             // else branch should be maybe (because of concurrency) put into after update trigger
-            str_replace('[pk_seq]', '\'' . $pkSeq . '\'', <<<'EOT'
+            str_replace('[pk_seq]', '\'' . str_replace('\'', '\'\'', $pkSeq) . '\'', <<<'EOT'
                 CREATE TRIGGER {trigger}
                     BEFORE INSERT OR UPDATE
                     ON {table}
diff --git a/src/Persistence/Sql/Query.php b/src/Persistence/Sql/Query.php
index 9b8c41324..7b5fa753e 100644
--- a/src/Persistence/Sql/Query.php
+++ b/src/Persistence/Sql/Query.php
@@ -824,8 +824,8 @@ protected function _render_set_fields(): ?string
         $ret = [];
 
         if ($this->args['set']) {
-            foreach ($this->args['set'] as [$field/* , $value */ ]) {
-                $field = $this->consume($field, self::ESCAPE_IDENTIFIER);
+            foreach ($this->args['set'] as $pair) {
+                $field = $this->consume($pair[0], self::ESCAPE_IDENTIFIER);
 
                 $ret[] = $field;
             }
@@ -840,8 +840,8 @@ protected function _render_set_values(): ?string
         $ret = [];
 
         if ($this->args['set']) {
-            foreach ($this->args['set'] as [/* $field */, $value]) {
-                $value = $this->consume($value, self::ESCAPE_PARAM);
+            foreach ($this->args['set'] as $pair) {
+                $value = $this->consume($pair[1], self::ESCAPE_PARAM);
 
                 $ret[] = $value;
             }
@@ -1097,11 +1097,8 @@ public function dsql($properties = [])
      * method should be used for building parts of the query internally.
      *
      * @param string|array $properties
-     * @param array        $arguments
-     *
-     * @return Expression
      */
-    public function expr($properties = [], $arguments = null)
+    public function expr($properties = [], array $arguments = []): Expression
     {
         $c = $this->expression_class;
         $e = new $c($properties, $arguments);
diff --git a/src/Persistence/Static_.php b/src/Persistence/Static_.php
index 0e6853b4c..c3c75c254 100644
--- a/src/Persistence/Static_.php
+++ b/src/Persistence/Static_.php
@@ -27,7 +27,7 @@ class Static_ extends Array_
      *
      * @param array $data Static data in one of supported formats
      */
-    public function __construct(array $data = null)
+    public function __construct(array $data = [])
     {
         // chomp off first row, we will use it to deduct fields
         $row1 = reset($data);
diff --git a/src/Reference/HasOneSql.php b/src/Reference/HasOneSql.php
index f9e08dc37..4250846dd 100644
--- a/src/Reference/HasOneSql.php
+++ b/src/Reference/HasOneSql.php
@@ -65,9 +65,9 @@ public function addField(string $fieldName, string $theirFieldName = null, array
      * Add multiple expressions by calling addField several times. Fields
      * may contain 3 types of elements:.
      *
-     * [ 'name', 'surname' ] - will import those fields as-is
-     * [ 'full_name' => 'name', 'day_of_birth' => ['dob', 'type' => 'date'] ] - use alias and options
-     * [ ['dob', 'type' => 'date'] ]  - use options
+     * ['name', 'surname'] - will import those fields as-is
+     * ['full_name' => 'name', 'day_of_birth' => ['dob', 'type' => 'date']] - use alias and options
+     * [['dob', 'type' => 'date']]  - use options
      *
      * You may also use second param to specify parameters:
      *
diff --git a/tests/JoinArrayTest.php b/tests/JoinArrayTest.php
index da561c332..66da04302 100644
--- a/tests/JoinArrayTest.php
+++ b/tests/JoinArrayTest.php
@@ -49,9 +49,9 @@ public function testDirection(): void
 
         $this->expectException(Exception::class); // TODO not implemented yet, see https://github.com/atk4/data/issues/803
         $j = $m->join('contact4.foo_id', ['master_field' => 'test_id', 'reverse' => true]);
-        $this->assertTrue($this->getProtected($j, 'reverse'));
-        $this->assertSame('test_id', $this->getProtected($j, 'master_field'));
-        $this->assertSame('foo_id', $this->getProtected($j, 'foreign_field'));
+        // $this->assertTrue($this->getProtected($j, 'reverse'));
+        // $this->assertSame('test_id', $this->getProtected($j, 'master_field'));
+        // $this->assertSame('foo_id', $this->getProtected($j, 'foreign_field'));
     }
 
     public function testJoinException(): void
diff --git a/tests/JoinSqlTest.php b/tests/JoinSqlTest.php
index 9f0e5d722..19a27c879 100644
--- a/tests/JoinSqlTest.php
+++ b/tests/JoinSqlTest.php
@@ -31,9 +31,9 @@ public function testDirection(): void
 
         $this->expectException(Exception::class); // TODO not implemented yet, see https://github.com/atk4/data/issues/803
         $j = $m->join('contact4.foo_id', ['master_field' => 'test_id', 'reverse' => true]);
-        $this->assertTrue($this->getProtected($j, 'reverse'));
-        $this->assertSame('test_id', $this->getProtected($j, 'master_field'));
-        $this->assertSame('foo_id', $this->getProtected($j, 'foreign_field'));
+        // $this->assertTrue($this->getProtected($j, 'reverse'));
+        // $this->assertSame('test_id', $this->getProtected($j, 'master_field'));
+        // $this->assertSame('foo_id', $this->getProtected($j, 'foreign_field'));
     }
 
     public function testDirectionException(): void
diff --git a/tests/Model/Smbo/Company.php b/tests/Model/Smbo/Company.php
deleted file mode 100644
index 329c7b36a..000000000
--- a/tests/Model/Smbo/Company.php
+++ /dev/null
@@ -1,35 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Atk4\Data\Tests\Model\Smbo;
-
-use Atk4\Data\Model;
-
-class Company extends Model
-{
-    public $table = 'system';
-
-    protected function init(): void
-    {
-        parent::init();
-
-        // Company data is stored in 3 tables actually.
-        $j_contractor = $this->join('contractor');
-        $j_company = $j_contractor->join('company.contractor_id', ['prefix' => 'company_']);
-
-        $j_contractor->addFields([
-            ['name', 'actual' => 'legal_name'],
-        ]);
-
-        $j_company->addFields([
-            ['business_start', 'type' => 'date'],
-            ['director_name'],
-            ['vat_calculation_type', 'enum' => ['cash', 'invoice']],
-        ]);
-
-        $this->addFields([
-            ['is_vat_registered', 'type' => 'boolean'],
-        ]);
-    }
-}
diff --git a/tests/Model/Smbo/Contact.php b/tests/Model/Smbo/Contact.php
deleted file mode 100644
index de94aa8ee..000000000
--- a/tests/Model/Smbo/Contact.php
+++ /dev/null
@@ -1,21 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Atk4\Data\Tests\Model\Smbo;
-
-use Atk4\Data\Model;
-
-class Contact extends Model
-{
-    public $table = 'contact';
-
-    protected function init(): void
-    {
-        parent::init();
-
-        $this->addField('type', ['enum' => ['client', 'supplier']]);
-
-        $this->addField('name');
-    }
-}
diff --git a/tests/Model/Smbo/Document.php b/tests/Model/Smbo/Document.php
index 467988797..c582a5c6d 100644
--- a/tests/Model/Smbo/Document.php
+++ b/tests/Model/Smbo/Document.php
@@ -14,10 +14,6 @@ protected function init(): void
     {
         parent::init();
 
-        // Documest is sent from one Contact to Another
-        $this->hasOne('contact_from_id', ['model' => [Contact::class]]);
-        $this->hasOne('contact_to_id', ['model' => [Contact::class]]);
-
         $this->addField('doc_type', ['enum' => ['invoice', 'payment']]);
 
         $this->addField('amount', ['type' => 'atk4_money']);
diff --git a/tests/Persistence/Sql/ConnectionTest.php b/tests/Persistence/Sql/ConnectionTest.php
index 04432a5bd..189fca185 100644
--- a/tests/Persistence/Sql/ConnectionTest.php
+++ b/tests/Persistence/Sql/ConnectionTest.php
@@ -35,9 +35,6 @@ public function getName()
     }
 }
 
-/**
- * @coversDefaultClass \Atk4\Data\Persistence\Sql\Connection
- */
 class ConnectionTest extends TestCase
 {
     public function testInit(): void
diff --git a/tests/Persistence/Sql/ExceptionTest.php b/tests/Persistence/Sql/ExceptionTest.php
index e4b0ba91e..297b9953a 100644
--- a/tests/Persistence/Sql/ExceptionTest.php
+++ b/tests/Persistence/Sql/ExceptionTest.php
@@ -8,14 +8,8 @@
 use Atk4\Data\Persistence\Sql\Exception as SqlException;
 use Atk4\Data\Persistence\Sql\Expression;
 
-/**
- * @coversDefaultClass \Atk4\Data\Persistence\Sql\Exception
- */
 class ExceptionTest extends TestCase
 {
-    /**
-     * @covers ::__construct
-     */
     public function testException1(): void
     {
         $this->expectException(SqlException::class);
diff --git a/tests/Persistence/Sql/ExpressionTest.php b/tests/Persistence/Sql/ExpressionTest.php
index 163a8c73b..01454ecac 100644
--- a/tests/Persistence/Sql/ExpressionTest.php
+++ b/tests/Persistence/Sql/ExpressionTest.php
@@ -10,10 +10,8 @@
 use Atk4\Data\Persistence\Sql\Expressionable;
 use Atk4\Data\Persistence\Sql\Mysql;
 use Atk4\Data\Persistence\Sql\Query;
+use Atk4\Data\Persistence\Sql\Sqlite;
 
-/**
- * @coversDefaultClass \Atk4\Data\Persistence\Sql\Expression
- */
 class ExpressionTest extends TestCase
 {
     /**
@@ -24,46 +22,6 @@ public function e(...$args): Expression
         return new Expression(...$args);
     }
 
-    /**
-     * Test constructor exception - wrong 1st parameter.
-     *
-     * @covers ::__construct
-     */
-    public function testConstructorException1st1(): void
-    {
-        $this->expectException(Exception::class);
-        $this->e(null);
-    }
-
-    /**
-     * Test constructor exception - wrong 1st parameter.
-     *
-     * @covers ::__construct
-     */
-    public function testConstructorException1st2(): void
-    {
-        $this->expectException(Exception::class);
-        $this->e(false);
-    }
-
-    /**
-     * Test constructor exception - wrong 2nd parameter.
-     */
-    public function testConstructorException2nd1(): void
-    {
-        $this->expectException(Exception::class);
-        $this->e('hello, []', false);
-    }
-
-    /**
-     * Test constructor exception - wrong 2nd parameter.
-     */
-    public function testConstructorException2nd2(): void
-    {
-        $this->expectException(Exception::class);
-        $this->e('hello, []', 'hello');
-    }
-
     /**
      * Test constructor exception - no arguments (template is not defined).
      */
@@ -75,8 +33,6 @@ public function testConstructorException0arg(): void
 
     /**
      * Testing parameter edge cases - empty strings and arrays etc.
-     *
-     * @covers ::__construct
      */
     public function testConstructor1(): void
     {
@@ -89,9 +45,6 @@ public function testConstructor1(): void
     /**
      * Testing simple template patterns without arguments.
      * Testing different ways how to pass template to constructor.
-     *
-     * @covers ::__construct
-     * @covers ::escapeIdentifier
      */
     public function testConstructor2(): void
     {
@@ -100,21 +53,11 @@ public function testConstructor2(): void
             'now()',
             $this->e('now()')->render()[0]
         );
-        // pass as array without key
-        $this->assertSame(
-            'now()',
-            $this->e(['now()'])->render()[0]
-        );
         // pass as array with template key
         $this->assertSame(
             'now()',
             $this->e(['template' => 'now()'])->render()[0]
         );
-        // pass as array without key
-        $this->assertSame(
-            ':a Name',
-            $this->e(['[] Name'], ['First'])->render()[0]
-        );
         // pass as array with template key
         $this->assertSame(
             ':a Name',
@@ -124,8 +67,6 @@ public function testConstructor2(): void
 
     /**
      * Testing template with simple arguments.
-     *
-     * @covers ::__construct
      */
     public function testConstructor3(): void
     {
@@ -144,8 +85,6 @@ public function testConstructor3(): void
 
     /**
      * Testing template with complex arguments.
-     *
-     * @covers ::__construct
      */
     public function testConstructor4(): void
     {
@@ -240,10 +179,6 @@ public function provideNoTemplatingInSqlStringData(): iterable
 
     /**
      * Test nested parameters.
-     *
-     * @covers ::__construct
-     * @covers ::escapeParam
-     * @covers ::getDebugQuery
      */
     public function testNestedParams(): void
     {
@@ -264,9 +199,6 @@ public function testNestedParams(): void
 
     /**
      * Tests where one expression with parameter is used within several other expressions.
-     *
-     * @covers ::__construct
-     * @covers ::render
      */
     public function testNestedExpressions(): void
     {
@@ -286,22 +218,8 @@ public function testNestedExpressions(): void
         $this->assertSame('Hello :a and good night', $s4);
     }
 
-    /**
-     * @covers ::__toString
-     */
-    /*
-    public function testToStringException1(): void
-    {
-        $e = new MyBadExpression('Hello');
-        $this->expectException(Exception::class);
-        $s = (string)$e;
-    }
-    */
-
     /**
      * expr() should return new Expression object and inherit connection from it.
-     *
-     * @covers ::expr
      */
     public function testExpr(): void
     {
@@ -311,10 +229,6 @@ public function testExpr(): void
 
     /**
      * Fully covers escapeIdentifier method.
-     *
-     * @covers ::escape
-     * @covers ::escapeIdentifier
-     * @covers ::escapeIdentifierSoft
      */
     public function testEscape(): void
     {
@@ -357,25 +271,10 @@ public function testEscape(): void
             '"users".*',
             $this->callProtected($this->e(), 'escapeIdentifierSoft', 'users.*')
         );
-
-        $this->assertSame(
-            '"first_name"',
-            $this->e()->escape('first_name')->render()[0]
-        );
-        $this->assertSame(
-            '"first""_name"',
-            $this->e()->escape('first"_name')->render()[0]
-        );
-        $this->assertSame(
-            '"first""_name {}"',
-            $this->e()->escape('first"_name {}')->render()[0]
-        );
     }
 
     /**
      * Fully covers escapeParam method.
-     *
-     * @covers ::escapeParam
      */
     public function testParam(): void
     {
@@ -386,9 +285,6 @@ public function testParam(): void
         ], $e->render());
     }
 
-    /**
-     * @covers ::consume
-     */
     public function testConsume(): void
     {
         $constants = (new \ReflectionClass(Expression::class))->getConstants();
@@ -411,16 +307,22 @@ public function testConsume(): void
             $this->callProtected($this->e(), 'consume', new Query())
         );
 
+        $myField = new class() implements Expressionable {
+            public function getDsqlExpression(Expression $expr): Expression
+            {
+                return $expr->expr('"myfield"');
+            }
+        };
+        $e = $this->e('hello, []', [$myField]);
+        $e->connection = new Sqlite\Connection();
         $this->assertSame(
             'hello, "myfield"',
-            $this->e('hello, []', [new MyField()])->render()[0]
+            $e->render()[0]
         );
     }
 
     /**
      * $escape_mode value is incorrect.
-     *
-     * @covers ::consume
      */
     public function testConsumeException1(): void
     {
@@ -430,8 +332,6 @@ public function testConsumeException1(): void
 
     /**
      * Only Expressionable objects may be used in Expression.
-     *
-     * @covers ::consume
      */
     public function testConsumeException2(): void
     {
@@ -439,12 +339,6 @@ public function testConsumeException2(): void
         $this->callProtected($this->e(), 'consume', new \stdClass());
     }
 
-    /**
-     * @covers ::offsetExists
-     * @covers ::offsetGet
-     * @covers ::offsetSet
-     * @covers ::offsetUnset
-     */
     public function testArrayAccess(): void
     {
         $e = $this->e('', ['parrot' => 'red', 'blue']);
@@ -477,26 +371,17 @@ public function testArrayAccess(): void
         $this->assertSame('coalesce(year(now()) - year(birth_date), :a)', $age->render()[0]);
     }
 
-    /**
-     * Test IteratorAggregate implementation.
-     *
-     * @covers ::getRowsIterator
-     *
-     * @doesNotPerformAssertions
-     */
-    public function testIteratorAggregate(): void
-    {
-        // TODO cannot test this without actual DB connection and executing expression
-    }
-
     /**
      * Test for vendors that rely on JavaScript expressions, instead of parameters.
-     *
-     * @coversNothing
      */
     public function testJsonExpression(): void
     {
-        $e = new JsonExpression('hello, [who]', ['who' => 'world']);
+        $e = new class('hello, [who]', ['who' => 'world']) extends Expression {
+            public function escapeParam($value): string
+            {
+                return json_encode($value);
+            }
+        };
 
         $this->assertSame([
             'hello, "world"',
@@ -504,24 +389,21 @@ public function testJsonExpression(): void
         ], $e->render());
     }
 
-    /**
-     * Test var-dump code for codecoverage.
-     *
-     * @covers ::__debugInfo
-     *
-     * @doesNotPerformAssertions
-     */
     public function testVarDump(): void
     {
-        $this->e('test')->__debugInfo();
+        $this->assertSame(
+            'test',
+            $this->e('test')->__debugInfo()['R']
+        );
 
-        $this->e(' [nosuchtag] ')->__debugInfo();
+        $this->assertStringContainsString(
+            'Expression could not render tag',
+            $this->e(' [nosuchtag] ')->__debugInfo()['R']
+        );
     }
 
     /**
      * Test reset().
-     *
-     * @covers ::reset
      */
     public function testReset(): void
     {
@@ -536,30 +418,3 @@ public function testReset(): void
         $this->assertSame(['custom' => ['name' => 'John']], $this->getProtected($e, 'args'));
     }
 }
-
-// @codingStandardsIgnoreStart
-class JsonExpression extends Expression
-{
-    public function escapeParam($value): string
-    {
-        return json_encode($value);
-    }
-}
-class MyField implements Expressionable
-{
-    public function getDsqlExpression(Expression $expr): Expression
-    {
-        return $expr->expr('"myfield"');
-    }
-}
-/*
-class MyBadExpression extends Expression
-{
-    public function getOne()
-    {
-        // should return string, but for test case we return array to get \Exception
-        return array();
-    }
-}
-*/
-// @codingStandardsIgnoreEnd
diff --git a/tests/Persistence/Sql/QueryTest.php b/tests/Persistence/Sql/QueryTest.php
index 860216681..ecfd53350 100644
--- a/tests/Persistence/Sql/QueryTest.php
+++ b/tests/Persistence/Sql/QueryTest.php
@@ -7,16 +7,9 @@
 use Atk4\Core\Phpunit\TestCase;
 use Atk4\Data\Persistence\Sql\Exception;
 use Atk4\Data\Persistence\Sql\Expression;
-use Atk4\Data\Persistence\Sql\Mssql;
 use Atk4\Data\Persistence\Sql\Mysql;
-use Atk4\Data\Persistence\Sql\Oracle;
-use Atk4\Data\Persistence\Sql\Postgresql;
 use Atk4\Data\Persistence\Sql\Query;
-use Atk4\Data\Persistence\Sql\Sqlite;
 
-/**
- * @coversDefaultClass \Atk4\Data\Persistence\Sql\Query
- */
 class QueryTest extends TestCase
 {
     /**
@@ -27,9 +20,6 @@ public function q(...$args): Query
         return new Query(...$args);
     }
 
-    /**
-     * @covers ::__construct
-     */
     public function testConstruct(): void
     {
         // passing properties in constructor
@@ -41,8 +31,6 @@ public function testConstruct(): void
 
     /**
      * dsql() should return new Query object and inherit connection from it.
-     *
-     * @covers ::dsql
      */
     public function testDsql(): void
     {
@@ -52,8 +40,6 @@ public function testDsql(): void
 
     /**
      * field() should return $this Query for chaining.
-     *
-     * @covers ::field
      */
     public function testFieldReturnValue(): void
     {
@@ -63,9 +49,6 @@ public function testFieldReturnValue(): void
 
     /**
      * Testing field - basic cases.
-     *
-     * @covers ::_render_field
-     * @covers ::field
      */
     public function testFieldBasic(): void
     {
@@ -109,9 +92,6 @@ public function testFieldBasic(): void
 
     /**
      * Testing field - defaultField.
-     *
-     * @covers ::_render_field
-     * @covers ::field
      */
     public function testFieldDefaultField(): void
     {
@@ -139,9 +119,6 @@ public function testFieldDefaultField(): void
 
     /**
      * Testing field - basic cases.
-     *
-     * @covers ::_render_field
-     * @covers ::field
      */
     public function testFieldExpression(): void
     {
@@ -178,9 +155,6 @@ public function testFieldExpression(): void
 
     /**
      * Duplicate alias of field.
-     *
-     * @covers ::_set_args
-     * @covers ::field
      */
     public function testFieldException1(): void
     {
@@ -191,8 +165,6 @@ public function testFieldException1(): void
     /**
      * Alias is NOT mandatory when pass table as Expression.
      *
-     * @covers ::table
-     *
      * @doesNotPerformAssertions
      */
     public function testTableException3(): void
@@ -203,8 +175,6 @@ public function testTableException3(): void
 
     /**
      * Alias is IS mandatory when pass table as Query.
-     *
-     * @covers ::table
      */
     public function testTableException4(): void
     {
@@ -214,9 +184,6 @@ public function testTableException4(): void
 
     /**
      * Table aliases should be unique.
-     *
-     * @covers ::_set_args
-     * @covers ::table
      */
     public function testTableException5(): void
     {
@@ -228,9 +195,6 @@ public function testTableException5(): void
 
     /**
      * Table aliases should be unique.
-     *
-     * @covers ::_set_args
-     * @covers ::table
      */
     public function testTableException6(): void
     {
@@ -242,9 +206,6 @@ public function testTableException6(): void
 
     /**
      * Table aliases should be unique.
-     *
-     * @covers ::_set_args
-     * @covers ::table
      */
     public function testTableException7(): void
     {
@@ -256,9 +217,6 @@ public function testTableException7(): void
 
     /**
      * Table aliases should be unique.
-     *
-     * @covers ::_set_args
-     * @covers ::table
      */
     public function testTableException8(): void
     {
@@ -270,9 +228,6 @@ public function testTableException8(): void
 
     /**
      * Table aliases should be unique.
-     *
-     * @covers ::_set_args
-     * @covers ::table
      */
     public function testTableException9(): void
     {
@@ -284,8 +239,6 @@ public function testTableException9(): void
 
     /**
      * Table can't be set as sub-Query in Update query mode.
-     *
-     * @covers ::table
      */
     public function testTableException10(): void
     {
@@ -299,8 +252,6 @@ public function testTableException10(): void
 
     /**
      * Table can't be set as sub-Query in Insert query mode.
-     *
-     * @covers ::table
      */
     public function testTableException11(): void
     {
@@ -314,8 +265,6 @@ public function testTableException11(): void
 
     /**
      * Requesting non-existant query mode should throw exception.
-     *
-     * @covers ::mode
      */
     public function testModeException1(): void
     {
@@ -325,8 +274,6 @@ public function testModeException1(): void
 
     /**
      * table() should return $this Query for chaining.
-     *
-     * @covers ::table
      */
     public function testTableReturnValue(): void
     {
@@ -334,11 +281,6 @@ public function testTableReturnValue(): void
         $this->assertSame($q, $q->table('employee'));
     }
 
-    /**
-     * @covers ::_render_table
-     * @covers ::_render_table_noalias
-     * @covers ::table
-     */
     public function testTableRender1(): void
     {
         // no table defined
@@ -433,10 +375,6 @@ public function testTableRender1(): void
         );
     }
 
-    /**
-     * @covers ::_render_table
-     * @covers ::table
-     */
     public function testTableRender2(): void
     {
         // pass table as expression or query
@@ -474,11 +412,6 @@ public function testTableRender2(): void
         );
     }
 
-    /**
-     * @covers ::render
-     * @covers \Atk4\Data\Persistence\Sql\Expression::consume
-     * @covers \Atk4\Data\Persistence\Sql\Expression::render
-     */
     public function testBasicRenderSubquery(): void
     {
         $age = new Expression('coalesce([age], [default_age])');
@@ -493,9 +426,6 @@ public function testBasicRenderSubquery(): void
         );
     }
 
-    /**
-     * @covers \Atk4\Data\Persistence\Sql\Expression::getDebugQuery
-     */
     public function testGetDebugQuery(): void
     {
         $age = new Expression('coalesce([age], [default_age], [foo], [bar])');
@@ -512,9 +442,6 @@ public function testGetDebugQuery(): void
         );
     }
 
-    /**
-     * @covers ::__debugInfo
-     */
     public function testVarDump(): void
     {
         $this->assertMatchesRegularExpression(
@@ -523,9 +450,6 @@ public function testVarDump(): void
         );
     }
 
-    /**
-     * @covers ::__debugInfo
-     */
     public function testVarDump2(): void
     {
         $this->assertStringContainsString(
@@ -534,9 +458,6 @@ public function testVarDump2(): void
         );
     }
 
-    /**
-     * @covers ::__debugInfo
-     */
     public function testVarDump3(): void
     {
         $this->assertStringContainsString(
@@ -545,9 +466,6 @@ public function testVarDump3(): void
         );
     }
 
-    /**
-     * @covers ::__debugInfo
-     */
     public function testVarDump4(): void
     {
         // should throw exception "Table cannot be Query in UPDATE, INSERT etc. query modes"
@@ -559,13 +477,6 @@ public function testVarDump4(): void
         );
     }
 
-    /**
-     * @covers ::_render_field
-     * @covers ::_render_table
-     * @covers ::field
-     * @covers ::render
-     * @covers ::table
-     */
     public function testUnionQuery(): void
     {
         // 1st query
@@ -633,8 +544,6 @@ public function testUnionQuery(): void
 
     /**
      * where() should return $this Query for chaining.
-     *
-     * @covers ::where
      */
     public function testWhereReturnValue(): void
     {
@@ -644,8 +553,6 @@ public function testWhereReturnValue(): void
 
     /**
      * having() should return $this Query for chaining.
-     *
-     * @covers ::field
      */
     public function testHavingReturnValue(): void
     {
@@ -655,10 +562,6 @@ public function testHavingReturnValue(): void
 
     /**
      * Basic where() tests.
-     *
-     * @covers ::_render_where
-     * @covers ::_sub_render_where
-     * @covers ::where
      */
     public function testWhereBasic(): void
     {
@@ -812,10 +715,6 @@ public function provideWhereUnsupportedOperatorData(): iterable
 
     /**
      * Testing where() with special values - null, array, like.
-     *
-     * @covers ::_render_where
-     * @covers ::_sub_render_where
-     * @covers ::where
      */
     public function testWhereSpecialValues(): void
     {
@@ -861,9 +760,6 @@ public function testWhereSpecialValues(): void
 
     /**
      * Having basically is the same as where, so we can relax and trouhly test where() instead.
-     *
-     * @covers ::_render_having
-     * @covers ::having
      */
     public function testBasicHaving(): void
     {
@@ -883,9 +779,6 @@ public function testBasicHaving(): void
 
     /**
      * Test Limit.
-     *
-     * @covers ::_render_limit
-     * @covers ::limit
      */
     public function testLimit(): void
     {
@@ -901,9 +794,6 @@ public function testLimit(): void
 
     /**
      * Test Order.
-     *
-     * @covers ::_render_order
-     * @covers ::order
      */
     public function testOrder(): void
     {
@@ -967,11 +857,11 @@ public function testOrder(): void
         );
         $this->assertSame(
             'order by "* desc"',
-            $this->q('[order]')->order($this->q()->escape('* desc'))->render()[0]
+            $this->q('[order]')->order($this->q()->expr('{}', ['* desc']))->render()[0]
         );
         $this->assertSame(
             'order by "* desc {}"',
-            $this->q('[order]')->order($this->q()->escape('* desc {}'))->render()[0]
+            $this->q('[order]')->order($this->q()->expr('{}', ['* desc {}']))->render()[0]
         );
         // custom sort order
         $this->assertSame(
@@ -986,8 +876,6 @@ public function testOrder(): void
 
     /**
      * If first argument is array, second argument must not be used.
-     *
-     * @covers ::order
      */
     public function testOrderException1(): void
     {
@@ -997,9 +885,6 @@ public function testOrderException1(): void
 
     /**
      * Test Group.
-     *
-     * @covers ::_render_group
-     * @covers ::group
      */
     public function testGroup(): void
     {
@@ -1043,9 +928,6 @@ public function testGroup(): void
         );
     }
 
-    /**
-     * Test groupConcat.
-     */
     public function testGroupConcatException(): void
     {
         // doesn't support groupConcat by default
@@ -1053,44 +935,19 @@ public function testGroupConcatException(): void
         $this->q()->groupConcat('foo');
     }
 
-    /**
-     * Test groupConcat.
-     *
-     * @covers ::groupConcat
-     */
-    public function testGroupConcat(): void
-    {
-        $q = new Mysql\Query();
-        $this->assertSame('group_concat(`foo` separator \'-\')', $q->groupConcat('foo', '-')->render()[0]);
-
-        $q = new Oracle\Query();
-        $this->assertSame('listagg("foo", :a) within group (order by "foo")', $q->groupConcat('foo', '-')->render()[0]);
-
-        $q = new Postgresql\Query();
-        $this->assertSame('string_agg("foo", :a)', $q->groupConcat('foo', '-')->render()[0]);
-
-        $q = new Sqlite\Query();
-        $this->assertSame('group_concat("foo", :a)', $q->groupConcat('foo', '-')->render()[0]);
-    }
-
     /**
      * Test expr().
-     *
-     * @covers ::expr
      */
     public function testExpr(): void
     {
         $this->assertSame(Expression::class, get_class($this->q()->expr('foo')));
 
         $q = new Mysql\Query();
-        $this->assertSame(\Atk4\Data\Persistence\Sql\Mysql\Expression::class, get_class($q->expr('foo')));
+        $this->assertSame(Mysql\Expression::class, get_class($q->expr('foo')));
     }
 
     /**
      * Test Join.
-     *
-     * @covers ::_render_join
-     * @covers ::join
      */
     public function testJoin(): void
     {
@@ -1149,10 +1006,6 @@ public function testJoin(): void
 
     /**
      * Combined execution of where() clauses.
-     *
-     * @covers ::_render_where
-     * @covers ::mode
-     * @covers ::where
      */
     public function testCombinedWhere(): void
     {
@@ -1202,13 +1055,6 @@ public function testCombinedWhere(): void
 
     /**
      * Test OrWhere and AndWhere without where condition. Should ignore them.
-     *
-     * @covers ::_render_andwhere
-     * @covers ::_render_orwhere
-     * @covers ::_render_where
-     * @covers ::andExpr
-     * @covers ::orExpr
-     * @covers ::where
      */
     public function testEmptyOrAndWhere(): void
     {
@@ -1225,13 +1071,6 @@ public function testEmptyOrAndWhere(): void
 
     /**
      * Test insert, update and delete templates.
-     *
-     * @covers ::_render_set
-     * @covers ::_render_set_fields
-     * @covers ::_render_set_values
-     * @covers ::mode
-     * @covers ::set
-     * @covers ::where
      */
     public function testInsertDeleteUpdate(): void
     {
@@ -1292,10 +1131,55 @@ public function testInsertDeleteUpdate(): void
         );
     }
 
+    public function testMiscInsert(): void
+    {
+        $data = [
+            'id' => null,
+            'system_id' => '3576',
+            'system' => null,
+            'created_dts' => 123,
+            'contractor_from' => null,
+            'contractor_to' => null,
+            'vat_rate_id' => null,
+            'currency_id' => null,
+            'vat_period_id' => null,
+            'journal_spec_id' => '147735',
+            'job_id' => '9341',
+            'nominal_id' => null,
+            'root_nominal_code' => null,
+            'doc_type' => null,
+            'is_cn' => 'N',
+            'doc_date' => null,
+            'ref_no' => '940 testingqq11111',
+            'po_ref' => null,
+            'total_gross' => '100.00',
+            'total_net' => null,
+            'total_vat' => null,
+            'exchange_rate' => 1.892134,
+            'note' => null,
+            'archive' => 'N',
+            'fx_document_id' => null,
+            'exchanged_total_net' => null,
+            'exchanged_total_gross' => null,
+            'exchanged_total_vat' => null,
+            'exchanged_total_a' => null,
+            'exchanged_total_b' => null,
+        ];
+
+        $q = $this->q();
+        $q->mode('insert');
+        foreach ($data as $k => $v) {
+            $q->set($k, $v);
+        }
+
+        $this->assertSame(
+            'insert into  ("' . implode('", "', array_keys($data)) . '") values (:a, :b, :c, :d, :e, :f, :g, :h, :i, :j, :k, :l, :m, :n, :o, :p, :q, :r, :s, :t, :u, :v, :w, :x, :y, :z, :aa, :ab, :ac, :ad)',
+            $q->render()[0]
+        );
+    }
+
     /**
      * set() should return $this Query for chaining.
-     *
-     * @covers ::set
      */
     public function testSetReturnValue(): void
     {
@@ -1305,8 +1189,6 @@ public function testSetReturnValue(): void
 
     /**
      * Value of type array is not supported by SQL.
-     *
-     * @covers ::set
      */
     public function testSetException1(): void
     {
@@ -1317,8 +1199,6 @@ public function testSetException1(): void
     /**
      * Field name can be expression.
      *
-     * @covers ::set
-     *
      * @doesNotPerformAssertions
      */
     public function testSetException2(): void
@@ -1328,12 +1208,6 @@ public function testSetException2(): void
 
     /**
      * Test nested OR and AND expressions.
-     *
-     * @covers ::_render_andwhere
-     * @covers ::_render_orwhere
-     * @covers ::andExpr
-     * @covers ::orExpr
-     * @covers ::where
      */
     public function testNestedOrAnd(): void
     {
@@ -1404,8 +1278,6 @@ public function testNestedOrAndHavingWithWhereException(): void
 
     /**
      * Test reset().
-     *
-     * @covers \Atk4\Data\Persistence\Sql\Expression::reset
      */
     public function testReset(): void
     {
@@ -1425,9 +1297,6 @@ public function testReset(): void
 
     /**
      * Test [option].
-     *
-     * @covers ::_render_option
-     * @covers ::option
      */
     public function testOption(): void
     {
@@ -1465,11 +1334,6 @@ public function testOption(): void
 
     /**
      * Test caseExpr (normal).
-     *
-     * @covers ::_render_case
-     * @covers ::caseElse
-     * @covers ::caseExpr
-     * @covers ::caseWhen
      */
     public function testCaseExprNormal(): void
     {
@@ -1494,11 +1358,6 @@ public function testCaseExprNormal(): void
 
     /**
      * Test caseExpr (short form).
-     *
-     * @covers ::_render_case
-     * @covers ::caseElse
-     * @covers ::caseExpr
-     * @covers ::caseWhen
      */
     public function testCaseExprShortForm(): void
     {
@@ -1546,8 +1405,6 @@ public function testCaseExprException2(): void
 
     /**
      * Tests exprNow() method.
-     *
-     * @covers ::exprNow
      */
     public function testExprNow(): void
     {
@@ -1659,24 +1516,4 @@ public function testWith(): void
             $q->render()[0]
         );
     }
-
-    public function testExists(): void
-    {
-        $this->assertSame(
-            'select exists (select * from "contacts" where "first_name" = :a)',
-            $this->q()->table('contacts')->where('first_name', 'John')->exists()->render()[0]
-        );
-
-        $q = new Oracle\Query();
-        $this->assertSame(
-            'select case when exists(select * from "contacts" where "first_name" = :xxaaaa) then 1 else 0 end from "DUAL"',
-            $q->table('contacts')->where('first_name', 'John')->exists()->render()[0]
-        );
-
-        $q = new Mssql\Query();
-        $this->assertSame(
-            'select case when exists(select * from [contacts] where [first_name] = :a) then 1 else 0 end',
-            $q->table('contacts')->where('first_name', 'John')->exists()->render()[0]
-        );
-    }
 }
diff --git a/tests/Persistence/Sql/RandomTest.php b/tests/Persistence/Sql/RandomTest.php
deleted file mode 100644
index 7db8a08c7..000000000
--- a/tests/Persistence/Sql/RandomTest.php
+++ /dev/null
@@ -1,110 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Atk4\Data\Tests\Persistence\Sql;
-
-use Atk4\Core\Phpunit\TestCase;
-use Atk4\Data\Persistence\Sql\Mysql;
-use Atk4\Data\Persistence\Sql\Oracle;
-use Atk4\Data\Persistence\Sql\Postgresql;
-use Atk4\Data\Persistence\Sql\Query;
-use Atk4\Data\Persistence\Sql\Sqlite;
-
-/**
- * @coversDefaultClass \Atk4\Data\Persistence\Sql\Query
- */
-class RandomTest extends TestCase
-{
-    /**
-     * @param string|array ...$args
-     */
-    public function q(...$args): Query
-    {
-        return new Query(...$args);
-    }
-
-    public function testMiscInsert(): void
-    {
-        $data = [
-            'id' => null,
-            'system_id' => '3576',
-            'system' => null,
-            'created_dts' => 123,
-            'contractor_from' => null,
-            'contractor_to' => null,
-            'vat_rate_id' => null,
-            'currency_id' => null,
-            'vat_period_id' => null,
-            'journal_spec_id' => '147735',
-            'job_id' => '9341',
-            'nominal_id' => null,
-            'root_nominal_code' => null,
-            'doc_type' => null,
-            'is_cn' => 'N',
-            'doc_date' => null,
-            'ref_no' => '940 testingqq11111',
-            'po_ref' => null,
-            'total_gross' => '100.00',
-            'total_net' => null,
-            'total_vat' => null,
-            'exchange_rate' => null,
-            'note' => null,
-            'archive' => 'N',
-            'fx_document_id' => null,
-            'exchanged_total_net' => null,
-            'exchanged_total_gross' => null,
-            'exchanged_total_vat' => null,
-            'exchanged_total_a' => null,
-            'exchanged_total_b' => null,
-        ];
-        $q = $this->q();
-        $q->mode('insert');
-        foreach ($data as $key => $val) {
-            $q->set($key, $val);
-        }
-        $this->assertSame(
-            'insert into  ("' . implode('", "', array_keys($data)) . '") values (:a, :b, :c, :d, :e, :f, :g, :h, :i, :j, :k, :l, :m, :n, :o, :p, :q, :r, :s, :t, :u, :v, :w, :x, :y, :z, :aa, :ab, :ac, :ad)',
-            $q->render()[0]
-        );
-    }
-
-    /**
-     * Confirms that group concat works for all the SQL vendors we support.
-     */
-    public function _groupConcatTest(string $expected, Query $q): void
-    {
-        $q->table('people');
-        $q->group('age');
-
-        $q->field('age');
-        $q->field($q->groupConcat('name', ','));
-
-        $q->groupConcat('name', ',');
-
-        $this->assertSame($expected, $q->render()[0]);
-    }
-
-    public function testGroupConcat(): void
-    {
-        $this->_groupConcatTest(
-            'select `age`, group_concat(`name` separator \',\') from `people` group by `age`',
-            new Mysql\Query()
-        );
-
-        $this->_groupConcatTest(
-            'select "age", group_concat("name", :a) from "people" group by "age"',
-            new Sqlite\Query()
-        );
-
-        $this->_groupConcatTest(
-            'select "age", string_agg("name", :a) from "people" group by "age"',
-            new Postgresql\Query()
-        );
-
-        $this->_groupConcatTest(
-            'select "age", listagg("name", :xxaaaa) within group (order by "name") from "people" group by "age"',
-            new Oracle\Query()
-        );
-    }
-}
diff --git a/tests/Persistence/Sql/WithDb/SelectTest.php b/tests/Persistence/Sql/WithDb/SelectTest.php
index 7cdd376ff..3314db5de 100644
--- a/tests/Persistence/Sql/WithDb/SelectTest.php
+++ b/tests/Persistence/Sql/WithDb/SelectTest.php
@@ -60,9 +60,8 @@ private function q($table = null, string $alias = null): Query
 
     /**
      * @param string|array $template
-     * @param array        $args
      */
-    private function e($template = [], array $args = null): Expression
+    private function e($template = [], array $args = []): Expression
     {
         return $this->c->expr($template, $args);
     }
@@ -106,11 +105,9 @@ public function testBasicQueries(): void
             $this->q()->field(new Expression('2 + 2'), 'now')->getRows()
         );
 
-        /*
-         * PostgreSQL needs to have values cast, to make the query work.
-         * But CAST(.. AS int) does not work in mysql. So we use two different tests..
-         * (CAST(.. AS int) will work on mariaDB, whereas mysql needs it to be CAST(.. AS signed))
-         */
+        // PostgreSQL needs to have values cast, to make the query work.
+        // But CAST(.. AS int) does not work in Mysql. So we use two different tests..
+        // (CAST(.. AS int) will work on MariaDB, whereas Mysql needs it to be CAST(.. AS signed))
         if ($this->getDatabasePlatform() instanceof PostgreSQLPlatform) {
             $this->assertSame(
                 [['now' => '6']],
@@ -131,12 +128,8 @@ public function testBasicQueries(): void
 
     public function testExpression(): void
     {
-        /*
-         * PostgreSQL, at least versions before 10, needs to have the string cast to the
-         * correct datatype.
-         * But using CAST(.. AS CHAR) will return one single character on postgresql, but the
-         * entire string on mysql.
-         */
+        // PostgreSQL, at least versions before 10, needs to have the string cast to the correct datatype.
+        // But using CAST(.. AS CHAR) will return a single character on PostgreSQL, but the entire string on MySQL.
         if ($this->getDatabasePlatform() instanceof PostgreSQLPlatform || $this->getDatabasePlatform() instanceof SQLServerPlatform) {
             $this->assertSame(
                 'foo',
@@ -240,6 +233,77 @@ public function testWhereExpression(): void
         );
     }
 
+    public function testGroupConcat(): void
+    {
+        $q = $this->q()
+            ->table('people')
+            ->group('age')
+            ->field('age')
+            ->field($this->q()->groupConcat('name', ','));
+
+        if ($this->getDatabasePlatform() instanceof MySQLPlatform) {
+            $this->assertSame([
+                'select `age`, group_concat(`name` separator \',\') from `people` group by `age`',
+                [],
+            ], $q->render());
+        } elseif ($this->getDatabasePlatform() instanceof PostgreSQLPlatform) {
+            $this->assertSame([
+                'select "age", string_agg("name", :a) from "people" group by "age"',
+                [':a' => ','],
+            ], $q->render());
+        } elseif ($this->getDatabasePlatform() instanceof SQLServerPlatform) {
+            $this->assertSame([
+                'select [age], string_agg([name], N\',\') from [people] group by [age]',
+                [],
+            ], $q->render());
+        } elseif ($this->getDatabasePlatform() instanceof OraclePlatform) {
+            $this->assertSame([
+                'select "age", listagg("name", :xxaaaa) within group (order by "name") from "people" group by "age"',
+                [':xxaaaa' => ','],
+            ], $q->render());
+        } else {
+            $this->assertSame([
+                'select "age", group_concat("name", :a) from "people" group by "age"',
+                [':a' => ','],
+            ], $q->render());
+        }
+    }
+
+    public function testExists(): void
+    {
+        $q = $this->q()
+            ->table('contacts')
+            ->where('first_name', 'John')
+            ->exists();
+
+        if ($this->getDatabasePlatform() instanceof MySQLPlatform) {
+            $this->assertSame([
+                'select exists (select * from `contacts` where `first_name` = :a)',
+                [':a' => 'John'],
+            ], $q->render());
+        } elseif ($this->getDatabasePlatform() instanceof PostgreSQLPlatform) {
+            $this->assertSame([
+                'select exists (select * from "contacts" where "first_name" = :a)',
+                [':a' => 'John'],
+            ], $q->render());
+        } elseif ($this->getDatabasePlatform() instanceof SQLServerPlatform) {
+            $this->assertSame([
+                'select case when exists(select * from [contacts] where [first_name] = :a) then 1 else 0 end',
+                [':a' => 'John'],
+            ], $q->render());
+        } elseif ($this->getDatabasePlatform() instanceof OraclePlatform) {
+            $this->assertSame([
+                'select case when exists(select * from "contacts" where "first_name" = :xxaaaa) then 1 else 0 end from "DUAL"',
+                [':xxaaaa' => 'John'],
+            ], $q->render());
+        } else {
+            $this->assertSame([
+                'select exists (select * from "contacts" where "first_name" = :a)',
+                [':a' => 'John'],
+            ], $q->render());
+        }
+    }
+
     public function testExecuteException(): void
     {
         $this->expectException(ExecuteException::class);
diff --git a/tests/RandomTest.php b/tests/RandomTest.php
index 62c35fabd..5cc0bff05 100644
--- a/tests/RandomTest.php
+++ b/tests/RandomTest.php
@@ -322,13 +322,14 @@ public function testUpdateCondition(): void
         $m->set('name', 'Peter');
 
         try {
+            $this->expectException(Exception::class);
+
             $m->save();
-            $e = null;
         } catch (\Exception $e) {
-        }
+            $this->assertEquals($dbData, $this->getDb());
 
-        $this->assertNotNull($e);
-        $this->assertEquals($dbData, $this->getDb());
+            throw $e;
+        }
     }
 
     public function testHookBreakers(): void
diff --git a/tests/ReferenceTest.php b/tests/ReferenceTest.php
index 34baedd6c..76c841212 100644
--- a/tests/ReferenceTest.php
+++ b/tests/ReferenceTest.php
@@ -80,6 +80,7 @@ public function testRefName1(): void
         $order->addField('user_id');
 
         $user->hasMany('Orders', ['model' => $order]);
+
         $this->expectException(Exception::class);
         $user->hasMany('Orders', ['model' => $order]);
     }
@@ -90,6 +91,7 @@ public function testRefName2(): void
         $user = new Model(null, ['table' => 'user']);
 
         $user->hasOne('user_id', ['model' => $user]);
+
         $this->expectException(Exception::class);
         $user->hasOne('user_id', ['model' => $user]);
     }
@@ -100,6 +102,7 @@ public function testRefName3(): void
         $order->addRef('archive', ['model' => function ($m) {
             return new $m(null, ['table' => $m->table . '_archive']);
         }]);
+
         $this->expectException(Exception::class);
         $order->addRef('archive', ['model' => function ($m) {
             return new $m(null, ['table' => $m->table . '_archive']);
diff --git a/tests/Schema/ModelTest.php b/tests/Schema/ModelTest.php
index 192ddb36c..fecaa0d39 100644
--- a/tests/Schema/ModelTest.php
+++ b/tests/Schema/ModelTest.php
@@ -6,8 +6,10 @@
 
 use Atk4\Data\Field\PasswordField;
 use Atk4\Data\Model;
+use Atk4\Data\Persistence\Sql\Expression;
 use Atk4\Data\Schema\TestCase;
 use Doctrine\DBAL\Platforms\OraclePlatform;
+use Doctrine\DBAL\Platforms\PostgreSQLPlatform;
 use Doctrine\DBAL\Platforms\SQLServerPlatform;
 
 class ModelTest extends TestCase
@@ -214,6 +216,53 @@ public function testCharacterTypeFieldLong(string $type, bool $isBinary, int $le
         $this->assertSame(2, $row['id']);
         $this->assertSame(strlen($str), strlen($row['v']));
         $this->assertTrue($str === $row['v']);
+
+        // remove once https://github.com/php/php-src/issues/8928 is fixed
+        if (str_starts_with($_ENV['DB_DSN'], 'oci8') && $length > 1000) {
+            return;
+        }
+
+        // functional test for Expression::escapeStringLiteral() method
+        $strRaw = $model->getPersistence()->typecastSaveField($model->getField('v'), $str);
+        $strRawSql = \Closure::bind(function () use ($model, $strRaw) {
+            return $model->expr('')->escapeStringLiteral($strRaw);
+        }, null, Expression::class)();
+        $query = $this->db->getConnection()->dsql()
+            ->field($model->expr($strRawSql));
+        $resRaw = $query->getOne();
+        if ($this->getDatabasePlatform() instanceof OraclePlatform && $isBinary) {
+            $this->assertNotSame(strlen($str), strlen($resRaw));
+        } else {
+            $this->assertSame(strlen($str), strlen($resRaw));
+            $this->assertTrue($str === $resRaw);
+        }
+        $res = $model->getPersistence()->typecastLoadField($model->getField('v'), $resRaw);
+        $this->assertSame(strlen($str), strlen($res));
+        $this->assertTrue($str === $res);
+
+        if (!$isBinary) {
+            $str = $this->makePseudoRandomString($isBinary, $length);
+
+            // PostgreSQL does not support \0 character
+            // https://stackoverflow.com/questions/1347646/postgres-error-on-insert-error-invalid-byte-sequence-for-encoding-utf8-0x0
+            if ($this->getDatabasePlatform() instanceof PostgreSQLPlatform) {
+                $str = str_replace("\0", '-', $str);
+            }
+
+            $this->assertSame($length, mb_strlen($str));
+            $strSql = \Closure::bind(function () use ($model, $str) {
+                return $model->expr('')->escapeStringLiteral($str);
+            }, null, Expression::class)();
+            $query = $this->db->getConnection()->dsql()
+                ->field($model->expr($strSql));
+            $res = $query->getOne();
+            if ($this->getDatabasePlatform() instanceof OraclePlatform && $length === 0) {
+                $this->assertNull($res);
+            } else {
+                $this->assertSame(strlen($str), strlen($res));
+                $this->assertTrue($str === $res);
+            }
+        }
     }
 
     public function providerCharacterTypeFieldLongData(): array
diff --git a/tests/ScopeTest.php b/tests/ScopeTest.php
index ea27847f9..7627b38f6 100644
--- a/tests/ScopeTest.php
+++ b/tests/ScopeTest.php
@@ -131,11 +131,11 @@ public function testConditionToWords(): void
 
         $condition = new Condition('country_id/code', 'US');
 
-        $this->assertEquals('User that has reference Country Id where Code is equal to \'US\'', $condition->toWords($user));
+        $this->assertEquals('User that has reference Country ID where Code is equal to \'US\'', $condition->toWords($user));
 
         $condition = new Condition('country_id', 2);
 
-        $this->assertEquals('Country Id is equal to 2 (\'Latvia\')', $condition->toWords($user));
+        $this->assertEquals('Country ID is equal to 2 (\'Latvia\')', $condition->toWords($user));
 
         if ($this->getDatabasePlatform() instanceof SqlitePlatform) {
             $condition = new Condition('name', $user->expr('[surname]'));
@@ -145,7 +145,7 @@ public function testConditionToWords(): void
 
         $condition = new Condition('country_id', null);
 
-        $this->assertEquals('Country Id is equal to empty', $condition->toWords($user));
+        $this->assertEquals('Country ID is equal to empty', $condition->toWords($user));
 
         $condition = new Condition('name', '>', 'Test');
 
@@ -153,7 +153,7 @@ public function testConditionToWords(): void
 
         $condition = (new Condition('country_id', 2))->negate();
 
-        $this->assertEquals('Country Id is not equal to 2 (\'Latvia\')', $condition->toWords($user));
+        $this->assertEquals('Country ID is not equal to 2 (\'Latvia\')', $condition->toWords($user));
 
         $condition = new Condition($user->getField('surname'), $user->getField('name'));
 
diff --git a/tests/SmboTransferTest.php b/tests/SmboTransferTest.php
index 9b5fcac0b..0999b2d85 100644
--- a/tests/SmboTransferTest.php
+++ b/tests/SmboTransferTest.php
@@ -6,7 +6,6 @@
 
 use Atk4\Data\Schema\TestCase;
 use Atk4\Data\Tests\Model\Smbo\Account;
-use Atk4\Data\Tests\Model\Smbo\Company;
 use Atk4\Data\Tests\Model\Smbo\Payment;
 use Atk4\Data\Tests\Model\Smbo\Transfer;
 
@@ -24,8 +23,6 @@ protected function setUp(): void
         $this->createMigrator()->table('document')
             ->id()
             ->field('reference')
-            ->field('contact_from_id')
-            ->field('contact_to_id')
             ->field('doc_type')
             ->field('amount', ['type' => 'float'])
             ->create();
@@ -103,77 +100,4 @@ public function testRef(): void
             ['amount' => 20.0],
         ], $data);
     }
-
-    /*
-    public function testBasicEntities(): void
-    {
-        // Create a new company
-        $company = new Company($this->db);
-        $company->set([
-            'name' => 'Test Company 1',
-            'director_name' => 'Tester Little',
-            'type' => 'Limited Company',
-            'vat_registered' => true,
-        ]);
-        $company->save();
-
-        return;
-
-        // Create two new clients, one is sole trader, other is limited company
-        $client = $company->ref('Client');
-        [$john_id, $agile_id] = $m->insert([
-            ['name' => 'John Smith Consulting', 'vat_registered' => false],
-            'Agile Software Limited',
-        ]);
-
-        // Insert a first, default invoice for our sole-trader
-        $john = $company->load($john_id);
-        $john_invoices = $john->ref('Invoice');
-        $john_invoices->insertInvoice([
-            'ref_no' => 'INV1',
-            'due_date' => (new Date())->add(new DateInterval('2w')), // due in 2 weeks
-            'lines' => [
-                ['descr' => 'Sold some sweets', 'total_gross' => 100.0],
-                ['descr' => 'Delivery', 'total_gross' => 10.0],
-            ],
-        ]);
-
-        // Use custom method to create a sub-nominal
-        $company->ref('Nominal')->insertSubNominal('Sales', 'Discounted');
-
-        // Insert our second invoice using set referencing
-        $company->ref('Client')->load($agile_id)->refSet('Invoice')->insertInvoice([
-            'lines' => [
-                [
-                    'item_id' => $john->ref('Product')->insert('Cat Food'),
-                    'nominal' => 'Sales:Discounted',
-                    'total_net' => 50.0,
-                    'vat_rate' => 23,
-                    // calculates total_gross at 61.5
-                ],
-                [
-                    'item_id' => $john->ref('Service')->insert('Delivery'),
-                    'total_net' => 10.0,
-                    'vat_rate' => '23%',
-                    // calculates total_gross at 12.3
-                ],
-            ],
-        ]);
-
-        // Next we create bank account
-        $hsbc = $john->ref('Account')->set('name', 'HSBC')->save();
-
-        // And each of our invoices will have one new payment
-        foreach ($john_invoices as $invoice) {
-            $invoice->ref('Payment')->insert(['amount' => 10.2, 'bank_account_id' => $hsbc]);
-        }
-
-        // Now let's execute report
-        $debt = $john->add(new Model_Report_Debtors());
-
-        // This should give us total amount owed by all clients:
-        // (100.0 + 10.0) + (61.5 + 12.3) - 10.2 * 2
-        $this->assertSame(163.4, $debt->sum('amount'));
-    }
-     */
 }
diff --git a/tests/SubTypesTest.php b/tests/SubTypesTest.php
index da35dee7d..cb8672144 100644
--- a/tests/SubTypesTest.php
+++ b/tests/SubTypesTest.php
@@ -171,12 +171,29 @@ public function testBasic(): void
         $this->assertInstanceOf(StTransaction_TransferIn::class, $current->ref('Transactions')->load(3));
         $this->assertInstanceOf(StTransaction_Withdrawal::class, $current->ref('Transactions')->load(4));
 
-        $classes = [];
-        foreach ($current->ref('Transactions') as $tr) {
-            $classes[] = get_class($tr);
-        }
-        sort($classes);
-
-        $this->assertSame([StTransaction_TransferIn::class, StTransaction_Withdrawal::class], $classes);
+        $assertClassesFx = function (array $expectedClasses) use ($current): void {
+            $classes = [];
+            foreach ($current->ref('Transactions')->setOrder('id') as $tr) {
+                $classes[] = get_class($tr);
+            }
+            $this->assertSame($expectedClasses, $classes);
+        };
+
+        $assertClassesFx([
+            StTransaction_TransferIn::class,
+            StTransaction_Withdrawal::class,
+        ]);
+
+        $current->deposit(50);
+        $current->deposit(50);
+        $this->assertInstanceOf(StTransaction_Deposit::class, $current->ref('Transactions')->load(5));
+        $this->assertInstanceOf(StTransaction_Deposit::class, $current->ref('Transactions')->load(5));
+
+        $assertClassesFx([
+            StTransaction_TransferIn::class,
+            StTransaction_Withdrawal::class,
+            StTransaction_Deposit::class,
+            StTransaction_Deposit::class,
+        ]);
     }
 }
diff --git a/tests/UserActionTest.php b/tests/UserActionTest.php
index 7caacf7a3..b7d666d44 100644
--- a/tests/UserActionTest.php
+++ b/tests/UserActionTest.php
@@ -123,8 +123,9 @@ public function testPreview(): void
 
     public function testPreviewFail(): void
     {
-        $this->expectExceptionMessage('specify preview callback');
         $client = new UaClient($this->pers);
+
+        $this->expectExceptionMessage('specify preview callback');
         $client->getUserAction('backup_clients')->preview();
     }
 
@@ -159,8 +160,9 @@ public function testAppliesTo3(): void
 
     public function testException1(): void
     {
-        $this->expectException(\Atk4\Core\Exception::class);
         $client = new UaClient($this->pers);
+
+        $this->expectException(\Atk4\Core\Exception::class);
         $client->getUserAction('non_existant_action');
     }
 
@@ -224,9 +226,9 @@ public function testFieldsTooDirty1(): void
         $this->assertNotSame('Peter', $client->get('name'));
         $client->set('name', 'Peter');
         $client->set('reminder_sent', true);
+
         $this->expectExceptionMessage('dirty fields');
         $client->getUserAction('change_details')->execute();
-        $this->assertSame('Peter', $client->get('name'));
     }
 
     public function testFieldsIncorrect(): void
@@ -238,9 +240,9 @@ public function testFieldsIncorrect(): void
 
         $this->assertNotSame('Peter', $client->get('name'));
         $client->set('name', 'Peter');
+
         $this->expectExceptionMessage('must be either array or boolean');
         $client->getUserAction('change_details')->execute();
-        $this->assertSame('Peter', $client->get('name'));
     }
 
     public function testConfirmation(): void
diff --git a/tests/ValidationTest.php b/tests/ValidationTest.php
index 9a6deab1c..0cc24a78e 100644
--- a/tests/ValidationTest.php
+++ b/tests/ValidationTest.php
@@ -95,12 +95,13 @@ public function testValidate4(): void
         try {
             $m->set('name', 'Python');
             $m->set('domain', 'example.com');
+
+            $this->expectException(ValidationException::class);
             $m->save();
-            $this->fail('Expected exception');
-        } catch (\Atk4\Data\ValidationException $e) {
+        } catch (ValidationException $e) {
             $this->assertSame('This domain is reserved for examples only', $e->getParams()['errors']['domain']);
 
-            return;
+            throw $e;
         }
     }
 
@@ -115,10 +116,9 @@ public function testValidate5(): void
         $m->save();
     }
 
-    public function testValidateHook(): void
+    public function testValidateHook1(): void
     {
         $m = $this->m->createEntity();
-
         $m->onHook(Model::HOOK_VALIDATE, static function ($m) {
             if ($m->get('name') === 'C#') {
                 return ['name' => 'No sharp objects allowed'];
@@ -130,19 +130,38 @@ public function testValidateHook(): void
 
         try {
             $m->set('name', 'C#');
+
+            $this->expectException(ValidationException::class);
             $m->save();
-            $this->fail('Expected exception');
-        } catch (\Atk4\Data\ValidationException $e) {
+        } catch (ValidationException $e) {
             $this->assertSame('No sharp objects allowed', $e->errors['name']);
+
+            throw $e;
         }
+    }
+
+    public function testValidateHook2(): void
+    {
+        $m = $this->m->createEntity();
+        $m->onHook(Model::HOOK_VALIDATE, static function ($m) {
+            if ($m->get('name') === 'C#') {
+                return ['name' => 'No sharp objects allowed'];
+            }
+        });
+
+        $m->set('name', 'Swift');
+        $m->save();
 
         try {
             $m->set('name', 'Python');
             $m->set('domain', 'example.com');
+
+            $this->expectException(ValidationException::class);
             $m->save();
-            $this->fail('Expected exception');
-        } catch (\Atk4\Data\ValidationException $e) {
+        } catch (ValidationException $e) {
             $this->assertCount(2, $e->errors);
+
+            throw $e;
         }
     }
 }