diff --git a/composer.json b/composer.json
index c4d91da..1537463 100644
--- a/composer.json
+++ b/composer.json
@@ -37,6 +37,7 @@
         "gitonomy/gitlib": "^1.3",
         "guzzlehttp/guzzle": "^7.5",
         "guzzlehttp/psr7": "^2.4",
+        "httpsoft/http-message": "^1.1",
         "psr/container": "^2.0",
         "psr/http-factory": "^1.0",
         "psr/http-message": "^1.0",
@@ -65,12 +66,14 @@
         "roave/infection-static-analysis-plugin": "^1.16",
         "spatie/phpunit-watcher": "^1.23",
         "vimeo/psalm": "^5.22",
-        "yiisoft/active-record": "3.0.x-dev",
+        "yiisoft/active-record": "dev-master",
         "yiisoft/assets": "^4.0",
         "yiisoft/csrf": "^2.0",
+        "yiisoft/db": "1.2 as dev-master",
         "yiisoft/db-sqlite": "^1.0",
         "yiisoft/psr-dummy-provider": "^1.0",
         "yiisoft/router-fastroute": "^3.0",
+        "yiisoft/test-support": "^3.0",
         "yiisoft/yii-cycle": "dev-master",
         "yiisoft/yii-view": "^6.0"
     },
diff --git a/src/Debug/Provider/DebugApiProvider.php b/src/Debug/Provider/DebugApiProvider.php
index d62d5be..2a0977a 100644
--- a/src/Debug/Provider/DebugApiProvider.php
+++ b/src/Debug/Provider/DebugApiProvider.php
@@ -4,7 +4,6 @@
 
 namespace Yiisoft\Yii\Debug\Api\Debug\Provider;
 
-use Psr\Container\ContainerInterface;
 use Yiisoft\Di\ServiceProviderInterface;
 use Yiisoft\Router\RouteCollectorInterface;
 use Yiisoft\Yii\Debug\Api\Debug\Middleware\DebugHeaders;
@@ -22,7 +21,7 @@ public function getDefinitions(): array
     public function getExtensions(): array
     {
         return [
-            RouteCollectorInterface::class => static function (ContainerInterface $container, RouteCollectorInterface $routeCollector) {
+            RouteCollectorInterface::class => static function (RouteCollectorInterface $routeCollector) {
                 $routeCollector->prependMiddleware(DebugHeaders::class);
                 return $routeCollector;
             },
diff --git a/src/Debug/Repository/CollectorRepository.php b/src/Debug/Repository/CollectorRepository.php
index e37324b..777963e 100644
--- a/src/Debug/Repository/CollectorRepository.php
+++ b/src/Debug/Repository/CollectorRepository.php
@@ -38,7 +38,7 @@ public function getObject(string $id, string $objectId): array|null
         $dump = $this->loadData(StorageInterface::TYPE_OBJECTS, $id);
 
         foreach ($dump as $name => $value) {
-            if (($pos = strrpos($name, "#$objectId")) !== false) {
+            if (($pos = strrpos((string)$name, "#$objectId")) !== false) {
                 return [substr($name, 0, $pos), $value];
             }
         }
diff --git a/src/Inspector/ApplicationState.php b/src/Inspector/ApplicationState.php
index 9996b20..1b73fd2 100644
--- a/src/Inspector/ApplicationState.php
+++ b/src/Inspector/ApplicationState.php
@@ -4,7 +4,10 @@
 
 namespace Yiisoft\Yii\Debug\Api\Inspector;
 
-class ApplicationState
+/**
+ * @internal
+ */
+final class ApplicationState
 {
-    public static $params;
+    public static array $params = [];
 }
diff --git a/src/Inspector/Command/BashCommand.php b/src/Inspector/Command/BashCommand.php
index 357e056..9485c99 100644
--- a/src/Inspector/Command/BashCommand.php
+++ b/src/Inspector/Command/BashCommand.php
@@ -38,7 +38,7 @@ public function run(): CommandResponse
             ->setTimeout(null)
             ->run();
 
-        $processOutput = $process->getOutput();
+        $processOutput = rtrim($process->getOutput());
 
         if (!$process->getExitCode() > 1) {
             return new CommandResponse(
diff --git a/tests/Support/Application/fail.sh b/tests/Support/Application/fail.sh
new file mode 100644
index 0000000..4bbf6fa
--- /dev/null
+++ b/tests/Support/Application/fail.sh
@@ -0,0 +1,2 @@
+echo 'failed'
+exit $1
diff --git a/tests/Support/StubCollector.php b/tests/Support/StubCollector.php
new file mode 100644
index 0000000..06abc04
--- /dev/null
+++ b/tests/Support/StubCollector.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Yii\Debug\Api\Tests\Support;
+
+use Yiisoft\Yii\Debug\Collector\CollectorInterface;
+
+final class StubCollector implements CollectorInterface
+{
+    public function __construct(private array $data = [])
+    {
+    }
+
+    public function getName(): string
+    {
+        return 'stub';
+    }
+
+    public function startup(): void
+    {
+    }
+
+    public function shutdown(): void
+    {
+    }
+
+    public function getCollected(): array
+    {
+        return $this->data;
+    }
+}
diff --git a/tests/Unit/Debug/Middleware/DebugHeadersTest.php b/tests/Unit/Debug/Middleware/DebugHeadersTest.php
new file mode 100644
index 0000000..f86459a
--- /dev/null
+++ b/tests/Unit/Debug/Middleware/DebugHeadersTest.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Yii\Debug\Api\Tests\Unit\Debug\Middleware;
+
+use HttpSoft\Message\Response;
+use HttpSoft\Message\ServerRequest;
+use PHPUnit\Framework\TestCase;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Yiisoft\Router\UrlGeneratorInterface;
+use Yiisoft\Yii\Debug\Api\Debug\Middleware\DebugHeaders;
+use Yiisoft\Yii\Debug\DebuggerIdGenerator;
+
+final class DebugHeadersTest extends TestCase
+{
+    public function testHeaders(): void
+    {
+        $urlGenerator = $this->createMock(UrlGeneratorInterface::class);
+        $urlGenerator->method('generate')->willReturnCallback(
+            fn (string $route, array $parameters) => $route . '?' . http_build_query($parameters)
+        );
+        $idGenerator = new DebuggerIdGenerator();
+        $expectedId = $idGenerator->getId();
+
+        $middleware = new DebugHeaders($idGenerator, $urlGenerator);
+        $response = $middleware->process(new ServerRequest(), $this->createRequestHandler());
+
+        $this->assertSame($expectedId, $response->getHeaderLine('X-Debug-Id'));
+        $this->assertSame('debug/api/view?id=' . $expectedId, $response->getHeaderLine('X-Debug-Link'));
+    }
+
+    protected function createRequestHandler(): RequestHandlerInterface
+    {
+        return new class () implements RequestHandlerInterface {
+            public function handle($request): ResponseInterface
+            {
+                return new Response(200);
+            }
+        };
+    }
+}
diff --git a/tests/Unit/Debug/Middleware/ResponseDataWrapperTest.php b/tests/Unit/Debug/Middleware/ResponseDataWrapperTest.php
new file mode 100644
index 0000000..634cc66
--- /dev/null
+++ b/tests/Unit/Debug/Middleware/ResponseDataWrapperTest.php
@@ -0,0 +1,138 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Yii\Debug\Api\Tests\Unit\Debug\Middleware;
+
+use HttpSoft\Message\Response;
+use HttpSoft\Message\ResponseFactory;
+use HttpSoft\Message\ServerRequest;
+use HttpSoft\Message\StreamFactory;
+use PHPUnit\Framework\TestCase;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Throwable;
+use Yiisoft\DataResponse\DataResponse;
+use Yiisoft\DataResponse\DataResponseFactory;
+use Yiisoft\Router\CurrentRoute;
+use Yiisoft\Yii\Debug\Api\Debug\Exception\NotFoundException;
+use Yiisoft\Yii\Debug\Api\Debug\Middleware\ResponseDataWrapper;
+
+final class ResponseDataWrapperTest extends TestCase
+{
+    public function testNotDataResponse(): void
+    {
+        $middleware = $this->createMiddleware();
+        $response = $middleware->process(new ServerRequest(), $this->createRequestHandler(new Response(200)));
+
+        $this->assertInstanceOf(ResponseInterface::class, $response);
+    }
+
+    public function testDataResponse(): void
+    {
+        $controllerRawResponse = ['id' => 1, 'name' => 'User name'];
+        $factory = $this->createDataResponseFactory();
+        $response = $factory->createResponse($controllerRawResponse);
+
+        $middleware = $this->createMiddleware();
+        $response = $middleware->process(new ServerRequest(), $this->createRequestHandler($response));
+
+        $this->assertInstanceOf(ResponseInterface::class, $response);
+        $this->assertInstanceOf(DataResponse::class, $response);
+
+        $this->assertEquals(200, $response->getStatusCode());
+        $this->assertEquals([
+            'id' => null,
+            'data' => $controllerRawResponse,
+            'error' => null,
+            'success' => true,
+        ], $response->getData());
+    }
+
+    public function testDataResponseErrorStatus(): void
+    {
+        $controllerRawResponse = ['id' => 1, 'name' => 'User name'];
+        $factory = $this->createDataResponseFactory();
+        $response = $factory->createResponse($controllerRawResponse, 400);
+
+        $middleware = $this->createMiddleware();
+        $response = $middleware->process(new ServerRequest(), $this->createRequestHandler($response));
+
+        $this->assertInstanceOf(ResponseInterface::class, $response);
+        $this->assertInstanceOf(DataResponse::class, $response);
+
+        $this->assertEquals(400, $response->getStatusCode());
+        $this->assertEquals([
+            'id' => null,
+            'data' => $controllerRawResponse,
+            'error' => null,
+            'success' => false,
+        ], $response->getData());
+    }
+
+    public function testDataResponseException(): void
+    {
+        $errorMessage = 'Test exception';
+        $middleware = $this->createMiddleware();
+        $response = $middleware->process(
+            new ServerRequest(),
+            $this->createExceptionRequestHandler(new NotFoundException($errorMessage))
+        );
+
+        $this->assertInstanceOf(ResponseInterface::class, $response);
+        $this->assertInstanceOf(DataResponse::class, $response);
+
+        $this->assertEquals(404, $response->getStatusCode());
+        $this->assertEquals([
+            'id' => null,
+            'data' => null,
+            'error' => $errorMessage,
+            'success' => false,
+        ], $response->getData());
+    }
+
+    private function createRequestHandler(ResponseInterface $response): RequestHandlerInterface
+    {
+        return new class ($response) implements RequestHandlerInterface {
+            public function __construct(
+                private ResponseInterface $response,
+            ) {
+            }
+
+            public function handle($request): ResponseInterface
+            {
+                return $this->response;
+            }
+        };
+    }
+
+    private function createExceptionRequestHandler(Throwable $exception): RequestHandlerInterface
+    {
+        return new class ($exception) implements RequestHandlerInterface {
+            public function __construct(
+                private Throwable $exception,
+            ) {
+            }
+
+            public function handle($request): ResponseInterface
+            {
+                throw $this->exception;
+            }
+        };
+    }
+
+    private function createMiddleware(): ResponseDataWrapper
+    {
+        $factory = $this->createDataResponseFactory();
+        $currentRoute = new CurrentRoute();
+        return new ResponseDataWrapper($factory, $currentRoute);
+    }
+
+    private function createDataResponseFactory(): DataResponseFactory
+    {
+        return new DataResponseFactory(
+            new ResponseFactory(),
+            new StreamFactory(),
+        );
+    }
+}
diff --git a/tests/Unit/Debug/Provider/DebugApiProviderTest.php b/tests/Unit/Debug/Provider/DebugApiProviderTest.php
new file mode 100644
index 0000000..0ca8861
--- /dev/null
+++ b/tests/Unit/Debug/Provider/DebugApiProviderTest.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Yii\Debug\Api\Tests\Unit\Debug\Provider;
+
+use PHPUnit\Framework\TestCase;
+use Yiisoft\Router\RouteCollectorInterface;
+use Yiisoft\Yii\Debug\Api\Debug\Middleware\DebugHeaders;
+use Yiisoft\Yii\Debug\Api\Debug\Provider\DebugApiProvider;
+
+final class DebugApiProviderTest extends TestCase
+{
+    public function testExtension(): void
+    {
+        $provider = new DebugApiProvider();
+
+        $this->assertIsArray($provider->getDefinitions());
+        $this->assertIsArray($provider->getExtensions());
+        $this->assertEmpty($provider->getDefinitions());
+
+        $extensions = $provider->getExtensions();
+        $this->assertArrayHasKey(RouteCollectorInterface::class, $extensions);
+
+        $routeCollectorDecorator = $extensions[RouteCollectorInterface::class];
+        $this->assertIsCallable($routeCollectorDecorator);
+
+        $routeCollector = $this->createMock(RouteCollectorInterface::class);
+        $routeCollector->expects($this->once())
+            ->method('prependMiddleware')
+            ->with(DebugHeaders::class)
+            ->willReturn($routeCollector);
+
+        $this->assertSame($routeCollector, $routeCollectorDecorator($routeCollector));
+    }
+}
diff --git a/tests/Unit/Debug/Repository/CollectorRepositoryTest.php b/tests/Unit/Debug/Repository/CollectorRepositoryTest.php
new file mode 100644
index 0000000..b62153b
--- /dev/null
+++ b/tests/Unit/Debug/Repository/CollectorRepositoryTest.php
@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Yii\Debug\Api\Tests\Unit\Debug\Repository;
+
+use PHPUnit\Framework\TestCase;
+use Yiisoft\Yii\Debug\Api\Debug\Repository\CollectorRepository;
+use Yiisoft\Yii\Debug\Api\Tests\Support\StubCollector;
+use Yiisoft\Yii\Debug\DebuggerIdGenerator;
+use Yiisoft\Yii\Debug\Storage\MemoryStorage;
+use Yiisoft\Yii\Debug\Storage\StorageInterface;
+
+final class CollectorRepositoryTest extends TestCase
+{
+    public function testSummary(): void
+    {
+        $idGenerator = new DebuggerIdGenerator();
+        $stubCollector = new StubCollector(['key' => 'value']);
+
+        $storage = $this->createStorage($idGenerator);
+        $repository = new CollectorRepository($storage);
+
+        $this->assertIsArray($repository->getSummary());
+        $this->assertEquals([
+            [
+                'id' => $idGenerator->getId(),
+                'collectors' => [],
+            ],
+        ], $repository->getSummary());
+
+        $storage->addCollector($stubCollector);
+
+        $this->assertIsArray($repository->getSummary());
+        $this->assertEquals([
+            [
+                'id' => $idGenerator->getId(),
+                'collectors' => [$stubCollector->getName()],
+            ],
+        ], $repository->getSummary());
+    }
+
+    public function testDetail(): void
+    {
+        $idGenerator = new DebuggerIdGenerator();
+        $stubCollector = new StubCollector(['key' => 'value']);
+
+        $storage = $this->createStorage($idGenerator);
+        $storage->addCollector($stubCollector);
+
+        $repository = new CollectorRepository($storage);
+
+        $this->assertIsArray($repository->getDetail($idGenerator->getId()));
+        $this->assertEquals([
+            $stubCollector->getName() => $stubCollector->getCollected(),
+        ], $repository->getDetail($idGenerator->getId()));
+    }
+
+    public function testDumpObject(): void
+    {
+        $idGenerator = new DebuggerIdGenerator();
+        $stubCollector = new StubCollector(['key' => 'value']);
+
+        $storage = $this->createStorage($idGenerator);
+        $storage->addCollector($stubCollector);
+
+        $repository = new CollectorRepository($storage);
+
+        $this->assertIsArray($repository->getDumpObject($idGenerator->getId()));
+        $this->assertEquals([
+            'key' => 'value',
+        ], $repository->getDumpObject($idGenerator->getId()));
+    }
+
+    public function testObject(): void
+    {
+        $idGenerator = new DebuggerIdGenerator();
+
+        $objectId = '123';
+        $stubCollector = new StubCollector([
+            'stdClass#' . $objectId => 'value',
+        ]);
+
+        $storage = $this->createStorage($idGenerator);
+        $storage->addCollector($stubCollector);
+
+        $repository = new CollectorRepository($storage);
+
+        $this->assertIsArray($repository->getObject($idGenerator->getId(), $objectId));
+        $this->assertEquals([
+            'stdClass',
+            'value',
+        ], $repository->getObject($idGenerator->getId(), $objectId));
+    }
+
+    private function createStorage(DebuggerIdGenerator $idGenerator): StorageInterface
+    {
+        return new MemoryStorage($idGenerator);
+    }
+}
diff --git a/tests/Unit/Inspector/ApplicationStateTest.php b/tests/Unit/Inspector/ApplicationStateTest.php
new file mode 100644
index 0000000..2b8aed5
--- /dev/null
+++ b/tests/Unit/Inspector/ApplicationStateTest.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Yii\Debug\Api\Tests\Unit\Inspector;
+
+use PHPUnit\Framework\TestCase;
+use Yiisoft\Yii\Debug\Api\Inspector\ApplicationState;
+
+final class ApplicationStateTest extends TestCase
+{
+    public function testStatus(): void
+    {
+        $this->assertEquals([], ApplicationState::$params);
+
+        ApplicationState::$params = ['key' => 'value'];
+        $this->assertEquals(['key' => 'value'], ApplicationState::$params);
+    }
+}
diff --git a/tests/Unit/Inspector/Command/BashCommandTest.php b/tests/Unit/Inspector/Command/BashCommandTest.php
new file mode 100644
index 0000000..5a327f7
--- /dev/null
+++ b/tests/Unit/Inspector/Command/BashCommandTest.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Yii\Debug\Api\Tests\Unit\Inspector\Command;
+
+use PHPUnit\Framework\TestCase;
+use Yiisoft\Aliases\Aliases;
+use Yiisoft\Yii\Debug\Api\Inspector\Command\BashCommand;
+use Yiisoft\Yii\Debug\Api\Inspector\CommandResponse;
+
+final class BashCommandTest extends TestCase
+{
+    public function testSuccess(): void
+    {
+        $aliases = new Aliases([
+            '@root' => __DIR__,
+        ]);
+        $command = new BashCommand($aliases, ['echo', 'test']);
+
+        $response = $command->run();
+
+        $this->assertSame(CommandResponse::STATUS_OK, $response->getStatus());
+        $this->assertSame('test', $response->getResult());
+        $this->assertSame([], $response->getErrors());
+    }
+
+    public function testError(): void
+    {
+        $aliases = new Aliases([
+            '@root' => dirname(__DIR__, 3) . '/Support/Application',
+        ]);
+        $command = new BashCommand($aliases, ['bash', 'fail.sh', '1']);
+
+        $response = $command->run();
+
+        $this->assertSame(CommandResponse::STATUS_ERROR, $response->getStatus());
+        $this->assertSame('failed', $response->getResult());
+        $this->assertSame([], $response->getErrors());
+    }
+}
diff --git a/tests/Unit/Inspector/CommandResponseTest.php b/tests/Unit/Inspector/CommandResponseTest.php
new file mode 100644
index 0000000..68b6428
--- /dev/null
+++ b/tests/Unit/Inspector/CommandResponseTest.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Yii\Debug\Api\Tests\Unit\Inspector;
+
+use PHPUnit\Framework\TestCase;
+use Yiisoft\Yii\Debug\Api\Inspector\CommandResponse;
+
+final class CommandResponseTest extends TestCase
+{
+    public function testStatus(): void
+    {
+        $response = new CommandResponse(CommandResponse::STATUS_OK, 'result', ['errors']);
+
+        $this->assertSame(CommandResponse::STATUS_OK, $response->getStatus());
+        $this->assertSame('result', $response->getResult());
+        $this->assertSame(['errors'], $response->getErrors());
+    }
+}
diff --git a/tests/Inspector/Database/DbSchemaProviderTest.php b/tests/Unit/Inspector/Database/DbSchemaProviderTest.php
similarity index 98%
rename from tests/Inspector/Database/DbSchemaProviderTest.php
rename to tests/Unit/Inspector/Database/DbSchemaProviderTest.php
index 0584e09..5a00506 100644
--- a/tests/Inspector/Database/DbSchemaProviderTest.php
+++ b/tests/Unit/Inspector/Database/DbSchemaProviderTest.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace Yiisoft\Yii\Debug\Api\Tests\Inspector\Database;
+namespace Yiisoft\Yii\Debug\Api\Tests\Unit\Inspector\Database;
 
 use PHPUnit\Framework\TestCase;
 use Yiisoft\Cache\NullCache;