Add test cases for tool execution success and failure

Introduce tests to verify tool execution behavior for both success and failure scenarios. These tests ensure proper handling of valid inputs and clear error reporting when execution fails. Also, update `injectPrivateProperty` to set property accessibility explicitly.

Author: klapaudius

tests/Command/TestMcpToolCommandTest.php

@@ -213,6 +213,7 @@ private function invokeGetToolInstanceMethod(): ToolInterface
     private function injectPrivateProperty(object $object, string $propertyName, mixed $value): void
     {
         $reflection = new \ReflectionProperty($object, $propertyName);
+        $reflection->setAccessible(true);
         $reflection->setValue($object, $value);
     }
 
@@ -457,6 +458,66 @@ public function test_list_all_tools_when_no_tools_are_configured_displays_warnin
         $this->assertEquals(Command::SUCCESS, $this->command->execute($this->inputMock, $this->outputMock));
     }
 
+    /**
+     * Tests that when valid input is provided, the tool is executed, and the result is displayed.
+     */
+    public function test_test_tool_valid_input_process_tool(): void
+    {
+        $toolMock = $this->createMock(ToolInterface::class);
+        $toolMock->method('getInputSchema')->willReturn([]);
+        $toolMock->method('execute')->with([])->willReturn(['success' => true]);
+
+        $this->containerMock
+            ->method('get')
+            ->willReturn($toolMock);
+
+        $this->containerMock
+            ->method('getParameter')
+            ->willReturn([HelloWorldTool::class]);
+
+        $this->inputMock
+            ->method('getArgument')
+            ->with('tool')
+            ->willReturn(HelloWorldTool::class);
+
+        $this->ioMock
+            ->expects($this->once())
+            ->method('success')
+            ->with('Tool executed successfully!');
+
+        $this->assertEquals(Command::SUCCESS, $this->command->execute($this->inputMock, $this->outputMock));
+    }
+
+    /**
+     * Tests that when the tool execution fails, the error message and stack trace are displayed.
+     */
+    public function test_test_tool_execution_failure_handles_error(): void
+    {
+        $toolMock = $this->createMock(ToolInterface::class);
+        $toolMock->method('getInputSchema')->willReturn([]);
+        $toolMock->method('execute')->willThrowException(new \RuntimeException('Execution error.'));
+
+        $this->containerMock
+            ->method('get')
+            ->willReturn($toolMock);
+
+        $this->containerMock
+            ->method('getParameter')
+            ->willReturn([HelloWorldTool::class]);
+
+        $this->inputMock
+            ->method('getArgument')
+            ->with('tool')
+            ->willReturn(HelloWorldTool::class);
+
+        $this->ioMock
+            ->expects($this->once())
+            ->method('error')
+            ->with($this->stringContains('Error executing tool'));
+
+        $this->assertEquals(Command::FAILURE, $this->command->execute($this->inputMock, $this->outputMock));
+    }
+
     /**
      * Tests that when valid tools are present, they are displayed in a table.
      */