diff --git a/CMakeLists.txt b/CMakeLists.txt
index 18ea34d..baff812 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -166,6 +166,7 @@ if(ZASM_BUILD_TESTS OR CMKR_ROOT_PROJECT) # tests
 		"src/tests/main.cpp"
 		"src/tests/tests/tests.assembler.cpp"
 		"src/tests/tests/tests.decoder.cpp"
+		"src/tests/tests/tests.error.cpp"
 		"src/tests/tests/tests.externals.cpp"
 		"src/tests/tests/tests.formatter.cpp"
 		"src/tests/tests/tests.imports.cpp"
diff --git a/src/tests/tests/tests.error.cpp b/src/tests/tests/tests.error.cpp
new file mode 100644
index 0000000..a8c7a63
--- /dev/null
+++ b/src/tests/tests/tests.error.cpp
@@ -0,0 +1,191 @@
+#include <chrono>
+#include <gtest/gtest.h>
+#include <zasm/core/errors.hpp>
+
+namespace zasm::tests
+{
+    TEST(ErrorTests, TestBasic)
+    {
+        Error error(ErrorCode::InvalidMode);
+        ASSERT_EQ(error, ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+    }
+
+    TEST(ErrorTests, TestExt)
+    {
+        Error error(ErrorCode::InvalidMode, "test message");
+        ASSERT_EQ(error, ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+    }
+
+    TEST(ErrorTests, TestExtClear)
+    {
+        Error error(ErrorCode::InvalidMode, "test message");
+        ASSERT_EQ(error, ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+
+        error.clear();
+        ASSERT_TRUE(error.empty());
+        ASSERT_EQ(error, ErrorCode::None);
+    }
+
+    TEST(ErrorTests, TestCopy1)
+    {
+        Error error(ErrorCode::InvalidMode);
+        ASSERT_EQ(error, ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+
+        Error error2(error);
+        ASSERT_EQ(error2, ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getCode(), ErrorCode::InvalidMode);
+    }
+
+    TEST(ErrorTests, TestCopy2)
+    {
+        Error error(ErrorCode::InvalidMode);
+        ASSERT_EQ(error, ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+
+        Error error2;
+        error2 = error;
+        ASSERT_EQ(error2, ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getCode(), ErrorCode::InvalidMode);
+    }
+
+    TEST(ErrorTests, TestCopyExt1)
+    {
+        Error error(ErrorCode::InvalidMode, "test message");
+        ASSERT_EQ(error, ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+
+        Error error2(error);
+        ASSERT_EQ(error2, ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getErrorMessage(), std::string("test message"));
+    }
+
+    TEST(ErrorTests, TestCopyExt2)
+    {
+        Error error(ErrorCode::InvalidMode, "test message");
+        ASSERT_EQ(error, ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+
+        Error error2;
+        error2 = error;
+        ASSERT_EQ(error2, ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getErrorMessage(), std::string("test message"));
+    }
+
+    TEST(ErrorTests, TestMoveExt1)
+    {
+        Error error(ErrorCode::InvalidMode, "test message");
+        ASSERT_EQ(error, ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+
+        Error error2(std::move(error));
+        ASSERT_EQ(error2, ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getErrorMessage(), std::string("test message"));
+
+        ASSERT_TRUE(error.empty());
+    }
+
+    TEST(ErrorTests, TestMoveExt2)
+    {
+        Error error(ErrorCode::InvalidMode, "test message");
+        ASSERT_EQ(error, ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+
+        Error error2;
+        error2 = std::move(error);
+        ASSERT_EQ(error2, ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getCode(), ErrorCode::InvalidMode);
+        ASSERT_EQ(error2.getErrorMessage(), std::string("test message"));
+
+        ASSERT_TRUE(error.empty());
+    }
+
+#if defined(_DEBUG) && 0
+    // Leak Tests.
+    // Disabled by default, this is a very crude way to test for memory leaks.
+    // The process runs for 5 seconds and creates/destroys Error objects in where we can observe
+    // if the memory usage is stable.
+
+    static constexpr auto kLeakTestDurationSecs = std::chrono::milliseconds(5000);
+
+    TEST(ErrorTests, TestLeak1)
+    {
+        auto start = std::chrono::high_resolution_clock::now();
+        while (std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now() - start)
+               < kLeakTestDurationSecs)
+        {
+            Error error(ErrorCode::InvalidMode, "test message");
+            ASSERT_EQ(error, ErrorCode::InvalidMode);
+            ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+            ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+        }
+    }
+
+    TEST(ErrorTests, TestLeak2)
+    {
+        auto start = std::chrono::high_resolution_clock::now();
+        while (std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now() - start)
+               < kLeakTestDurationSecs)
+        {
+            Error error(ErrorCode::InvalidMode, "test message");
+            ASSERT_EQ(error, ErrorCode::InvalidMode);
+            ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+            ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+
+            Error error2(std::move(error));
+            ASSERT_EQ(error2, ErrorCode::InvalidMode);
+            ASSERT_EQ(error2.getCode(), ErrorCode::InvalidMode);
+            ASSERT_EQ(error2.getErrorMessage(), std::string("test message"));
+        }
+    }
+
+    TEST(ErrorTests, TestLeak3)
+    {
+        auto start = std::chrono::high_resolution_clock::now();
+        while (std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now() - start)
+               < kLeakTestDurationSecs)
+        {
+            Error error(ErrorCode::InvalidMode, "test message");
+            ASSERT_EQ(error, ErrorCode::InvalidMode);
+            ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+            ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+
+            Error error2;
+            error2 = std::move(error);
+            ASSERT_EQ(error2, ErrorCode::InvalidMode);
+            ASSERT_EQ(error2.getCode(), ErrorCode::InvalidMode);
+            ASSERT_EQ(error2.getErrorMessage(), std::string("test message"));
+        }
+    }
+
+    TEST(ErrorTests, TestLeak4)
+    {
+        auto start = std::chrono::high_resolution_clock::now();
+        while (std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now() - start)
+               < kLeakTestDurationSecs)
+        {
+            Error error(ErrorCode::InvalidMode, "test message");
+            ASSERT_EQ(error, ErrorCode::InvalidMode);
+            ASSERT_EQ(error.getCode(), ErrorCode::InvalidMode);
+            ASSERT_EQ(error.getErrorMessage(), std::string("test message"));
+
+            error.clear();
+            ASSERT_TRUE(error.empty());
+            ASSERT_EQ(error, ErrorCode::None);
+        }
+    }
+#endif
+
+} // namespace zasm::tests