diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3729cdb..f447cad 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -2,6 +2,8 @@ name: CI
 
 on:
   push:
+    branches:
+      - master
   pull_request:
 
 env:
@@ -148,17 +150,19 @@ jobs:
         php-version:
           - "8.1"
 
+    services:
+      postgis:
+        image: "postgis/postgis:16-3.4"
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+        ports:
+          - "5432:5432"
+
     steps:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Setup PostgreSQL with PostGIS
-        uses: huaxk/postgis-action@v1
-        with:
-          postgresql version: 'latest'
-          postgresql password: 'postgres'
-          postgresql user: 'postgres'
-
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
diff --git a/tests/GeometryEngineTest.php b/tests/GeometryEngineTest.php
index 1bb2261..bfe5ac1 100644
--- a/tests/GeometryEngineTest.php
+++ b/tests/GeometryEngineTest.php
@@ -323,10 +323,10 @@ public static function providerPointOnSurface() : array
 
     /**
      * @param string $geometry The WKT of the geometry to test.
-     * @param string $boundary The WKT of the expected boundary.
+     * @param string|string[] $boundary The WKT of the expected boundary. If multiple possible results, an array.
      */
     #[DataProvider('providerBoundary')]
-    public function testBoundary(string $geometry, string $boundary) : void
+    public function testBoundary(string $geometry, string|array $boundary) : void
     {
         $geometryEngine = $this->getGeometryEngine();
 
@@ -344,16 +344,22 @@ public function testBoundary(string $geometry, string $boundary) : void
             $this->expectException(GeometryEngineException::class);
         }
 
-        self::assertSame($boundary, $geometryEngine->boundary($geometry)->asText());
+        $actualBoundary = $geometryEngine->boundary($geometry);
+
+        if (is_array($boundary)) {
+            self::assertContains($actualBoundary->asText(), $boundary);
+        } else {
+            self::assertSame($boundary, $actualBoundary->asText());
+        }
     }
 
     public static function providerBoundary() : array
     {
         return [
-            ['POINT (1 2)', 'GEOMETRYCOLLECTION EMPTY'],
-            ['POINT Z (2 3 4)', 'GEOMETRYCOLLECTION EMPTY'],
-            ['POINT M (3 4 5)', 'GEOMETRYCOLLECTION EMPTY'],
-            ['POINT ZM (4 5 6 7)', 'GEOMETRYCOLLECTION EMPTY'],
+            ['POINT (1 2)', ['POINT EMPTY', 'GEOMETRYCOLLECTION EMPTY']],
+            ['POINT Z (2 3 4)', ['POINT Z EMPTY', 'GEOMETRYCOLLECTION EMPTY']],
+            ['POINT M (3 4 5)', ['POINT M EMPTY', 'GEOMETRYCOLLECTION EMPTY']],
+            ['POINT ZM (4 5 6 7)', ['POINT ZM EMPTY', 'GEOMETRYCOLLECTION EMPTY']],
             ['LINESTRING (1 1, 0 0, -1 1)', 'MULTIPOINT (1 1, -1 1)'],
             ['POLYGON ((1 1, 0 0, -1 1, 1 1))', 'LINESTRING (1 1, 0 0, -1 1, 1 1)'],
         ];