diff --git a/tests/CommandlineTest.php b/tests/CommandlineTest.php
index 0d94b8f5f..0b2289602 100644
--- a/tests/CommandlineTest.php
+++ b/tests/CommandlineTest.php
@@ -12,22 +12,37 @@ class CommandlineTest extends OpenApiTestCase
 {
     use UsesExamples;
 
+    private function getCommandToExecute(string $cmd, ?string $devNullRedir = null): string
+    {
+        if (PHP_OS_FAMILY === 'Windows') {
+            $cmd = 'php ' . $cmd;
+            $devNull = 'NUL';
+        } else {
+            $devNull = '/dev/null';
+        }
+        if ($devNullRedir) {
+            $cmd .= " $devNullRedir $devNull";
+        }
+
+        return $cmd;
+    }
+
     public function testStdout(): void
     {
         $basePath = $this->examplePath('petstore');
         $path = "$basePath/annotations";
-        exec(__DIR__ . '/../bin/openapi --bootstrap ' . __DIR__ . '/cl_bootstrap.php --format yaml ' . escapeshellarg($path) . ' 2> /dev/null', $output, $retval);
+        exec($this->getCommandToExecute(__DIR__ . '/../bin/openapi --bootstrap ' . __DIR__ . '/cl_bootstrap.php --format yaml ' . escapeshellarg($path), '2>'), $output, $retval);
         $this->assertSame(0, $retval, implode(PHP_EOL, $output));
         $yaml = implode(PHP_EOL, $output);
         $this->assertSpecEquals(file_get_contents($this->getSpecFilename('petstore')), $yaml);
     }
 
-    public function testOutputTofile(): void
+    public function testOutputToFile(): void
     {
         $basePath = $this->examplePath('petstore');
         $path = "$basePath/annotations";
         $filename = sys_get_temp_dir() . '/swagger-php-clitest.yaml';
-        exec(__DIR__ . '/../bin/openapi --bootstrap ' . __DIR__ . '/cl_bootstrap.php --format yaml -o ' . escapeshellarg($filename) . ' ' . escapeshellarg($path) . ' 2> /dev/null', $output, $retval);
+        exec($this->getCommandToExecute(__DIR__ . '/../bin/openapi --bootstrap ' . __DIR__ . '/cl_bootstrap.php --format yaml -o ' . escapeshellarg($filename) . ' ' . escapeshellarg($path), '2>'), $output, $retval);
         $this->assertSame(0, $retval, implode(PHP_EOL, $output));
         $this->assertCount(0, $output, 'No output to stdout');
         $yaml = file_get_contents($filename);
@@ -40,7 +55,7 @@ public function testAddProcessor(): void
         $basePath = $this->examplePath('petstore');
         $path = "$basePath/annotations";
         $cmd = __DIR__ . '/../bin/openapi --bootstrap ' . __DIR__ . '/cl_bootstrap.php --processor OperationId --format yaml ' . escapeshellarg($path);
-        exec($cmd . ' 2> /dev/null', $output, $retval);
+        exec($this->getCommandToExecute($cmd, '2>'), $output, $retval);
         $this->assertSame(0, $retval, $cmd . PHP_EOL . implode(PHP_EOL, $output));
     }
 
@@ -48,7 +63,7 @@ public function testExcludeListWarning(): void
     {
         $basePath = $this->examplePath('petstore');
         $path = "$basePath/annotations";
-        exec(__DIR__ . '/../bin/openapi -e foo,bar ' . escapeshellarg($path) . ' 2>&1', $output, $retval);
+        exec($this->getCommandToExecute(__DIR__ . '/../bin/openapi -e foo,bar ' . escapeshellarg($path) . ' 2>&1'), $output, $retval);
         $this->assertSame(1, $retval);
         $output = implode(PHP_EOL, $output);
         $this->assertStringContainsString('Comma-separated exclude paths are deprecated', $output);
@@ -58,7 +73,7 @@ public function testMissingArg(): void
     {
         $basePath = $this->examplePath('petstore');
         $path = "$basePath/annotations";
-        exec(__DIR__ . '/../bin/openapi ' . escapeshellarg($path) . ' -e 2>&1', $output, $retval);
+        exec($this->getCommandToExecute(__DIR__ . '/../bin/openapi ' . escapeshellarg($path) . ' -e 2>&1'), $output, $retval);
         $this->assertSame(1, $retval);
         $output = implode(PHP_EOL, $output);
         $this->assertStringContainsString('Error: Missing argument for "-e"', $output);
diff --git a/tests/ContextTest.php b/tests/ContextTest.php
index 2fd363244..e1c75d494 100644
--- a/tests/ContextTest.php
+++ b/tests/ContextTest.php
@@ -58,7 +58,7 @@ public function testDebugLocation(): void
 
         $customerSchema = $openapi->components->schemas[0];
         $this->assertStringContainsString(
-            'Fixtures/Customer.php on line ',
+            'Fixtures' . DIRECTORY_SEPARATOR . 'Customer.php on line ',
             $customerSchema->_context->getDebugLocation()
         );
 
diff --git a/tests/UtilTest.php b/tests/UtilTest.php
index ca4107608..f8ec669bc 100644
--- a/tests/UtilTest.php
+++ b/tests/UtilTest.php
@@ -31,13 +31,25 @@ public function testFinder(): void
         $finder = (new Finder())->in($this->examplePath('using-traits/annotations'));
         $this->assertGreaterThan(0, iterator_count($finder), 'There should be at least a few files and a directory.');
         $finder_array = \iterator_to_array($finder);
-        $directory_path = $this->examplePath('using-traits/annotations/Decoration');
-        $this->assertArrayHasKey($directory_path, $finder_array, 'The directory should be a path in the finder.');
+        $normalize = static function (string $path): string {
+            return str_replace('\\', '/', $path);
+        };
+        $directory_path = $normalize($this->examplePath('using-traits/annotations/Decoration'));
+        $normalizePathKeys = static function ($paths) use ($normalize) {
+            return \array_combine(
+                \array_map(
+                    $normalize,
+                    \array_keys($paths)
+                ),
+                \array_values($paths)
+            );
+        };
+        $this->assertArrayHasKey($directory_path, $normalizePathKeys($finder_array), 'The directory should be a path in the finder.');
         // Use the Util method that should set the finder to only find files, since swagger-php only needs files.
         $finder_result = Util::finder($finder);
         $this->assertGreaterThan(0, iterator_count($finder_result), 'There should be at least a few file paths.');
         $finder_result_array = \iterator_to_array($finder_result);
-        $this->assertArrayNotHasKey($directory_path, $finder_result_array, 'The directory should not be a path in the finder.');
+        $this->assertArrayNotHasKey($directory_path, $normalizePathKeys($finder_result_array), 'The directory should not be a path in the finder.');
     }
 
     public static function shortenFixtures(): iterable