Use ::class constants in test assertions

Replace hardcoded class name strings with ::class constants in exception
message assertions for better maintainability and refactoring safety.

Author: OskarStark

src/agent/tests/AgentTest.php

@@ -104,7 +104,7 @@ public function testConstructorThrowsExceptionForInvalidInputProcessor()
         $invalidProcessor = new \stdClass();
 
         $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('Processor "stdClass" must implement "Symfony\AI\Agent\InputProcessorInterface".');
+        $this->expectExceptionMessage('Processor "stdClass" must implement "'.InputProcessorInterface::class.'".');
 
         /* @phpstan-ignore-next-line */
         new Agent($platform, $model, [$invalidProcessor]);
@@ -117,7 +117,7 @@ public function testConstructorThrowsExceptionForInvalidOutputProcessor()
         $invalidProcessor = new \stdClass();
 
         $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('Processor "stdClass" must implement "Symfony\AI\Agent\OutputProcessorInterface".');
+        $this->expectExceptionMessage('Processor "stdClass" must implement "'.OutputProcessorInterface::class.'".');
 
         /* @phpstan-ignore-next-line */
         new Agent($platform, $model, [], [$invalidProcessor]);

src/agent/tests/InputProcessor/ModelOverrideInputProcessorTest.php

@@ -22,6 +22,7 @@
 use Symfony\AI\Platform\Bridge\OpenAi\Embeddings;
 use Symfony\AI\Platform\Bridge\OpenAi\Gpt;
 use Symfony\AI\Platform\Message\MessageBag;
+use Symfony\AI\Platform\Model;
 
 #[CoversClass(ModelOverrideInputProcessor::class)]
 #[UsesClass(Gpt::class)]
@@ -58,7 +59,7 @@ public function testProcessInputWithoutModelOption()
     public function testProcessInputWithInvalidModelOption()
     {
         $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('Option "model" must be an instance of "Symfony\AI\Platform\Model".');
+        $this->expectExceptionMessage('Option "model" must be an instance of "'.Model::class.'".');
 
         $gpt = new Gpt();
         $model = new MessageBag();

src/agent/tests/Toolbox/ToolboxTest.php

@@ -162,7 +162,7 @@ public function testExecuteWithUnknownTool()
     public function testExecuteWithMisconfiguredTool()
     {
         $this->expectException(ToolConfigurationException::class);
-        $this->expectExceptionMessage('Method "foo" not found in tool "Symfony\AI\Fixtures\Tool\ToolMisconfigured".');
+        $this->expectExceptionMessage('Method "foo" not found in tool "'.ToolMisconfigured::class.'".');
 
         $toolbox = new Toolbox([new ToolMisconfigured()], new ReflectionToolFactory());