diff --git a/src/Exception/AbstractInvalidMiddlewareException.php b/src/Exception/AbstractInvalidMiddlewareException.php
new file mode 100644
index 0000000..f1b1e3b
--- /dev/null
+++ b/src/Exception/AbstractInvalidMiddlewareException.php
@@ -0,0 +1,153 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Middleware\Dispatcher\Exception;
+
+use InvalidArgumentException;
+use Psr\Http\Server\MiddlewareInterface;
+use Throwable;
+use Yiisoft\Definitions\Exception\InvalidConfigException;
+use Yiisoft\Definitions\Helpers\DefinitionValidator;
+use Yiisoft\FriendlyException\FriendlyExceptionInterface;
+use Yiisoft\Middleware\Dispatcher\Helper\DefinitionHelper;
+
+use function is_array;
+
+abstract class AbstractInvalidMiddlewareException extends InvalidArgumentException implements FriendlyExceptionInterface
+{
+    protected string $definitionString;
+
+    public function __construct(
+        protected mixed $definition,
+        string $message,
+        ?Throwable $previous = null,
+    ) {
+        $this->definitionString = DefinitionHelper::convertDefinitionToString($definition);
+
+        parent::__construct($message, 0, $previous);
+    }
+
+    public function getSolution(): ?string
+    {
+        $solution = [
+            <<<SOLUTION
+            ## Got definition value
+
+            `{$this->definitionString}`
+            SOLUTION
+        ];
+
+        $suggestion = $this->generateSuggestion();
+        if ($suggestion !== null) {
+            $solution[] = '## Suggestion';
+            $solution[] = $suggestion;
+        }
+
+        $solution[] = <<<SOLUTION
+        ## Middleware definition examples
+
+        PSR middleware class name:
+
+        ```php
+        Yiisoft\Session\SessionMiddleware::class
+        ```
+
+        PSR middleware array definition:
+
+        ```php
+        [
+            'class' => MyMiddleware::class,
+            '__construct()' => [
+                'someVar' => 42,
+            ],
+        ]
+        ```
+
+        Closure that returns `ResponseInterface`:
+
+        ```php
+        static function (): ResponseInterface {
+            return new Response(418);
+        },
+        ```
+
+        Closure that returns `MiddlewareInterface`:
+
+        ```php
+        static function (): MiddlewareInterface {
+            return new TestMiddleware();
+        }
+        ```
+
+        Action in controller:
+
+        ```php
+        [App\Backend\UserController::class, 'index']
+        ```
+
+        ## Related links
+
+        - [Array definition syntax](https://github.com/yiisoft/definitions#arraydefinition)
+        - [Callable PHP documentation](https://www.php.net/manual/language.types.callable.php)
+        SOLUTION;
+
+        return implode("\n\n", $solution);
+    }
+
+    private function generateSuggestion(): ?string
+    {
+        if (DefinitionHelper::isControllerWithNonExistAction($this->definition)) {
+            return <<<SOLUTION
+            Class `{$this->definition[0]}` exists, but does not contain method `{$this->definition[1]}()`.
+
+            Try adding `{$this->definition[1]}()` action to `{$this->definition[0]}` controller:
+
+            ```php
+            public function {$this->definition[1]}(): ResponseInterface
+            {
+                // TODO: Implement your action
+            }
+            ```
+            SOLUTION;
+        }
+
+        if (DefinitionHelper::isNotMiddlewareClassName($this->definition)) {
+            return sprintf(
+                'Class `%s` exists, but does not implement `%s`.',
+                $this->definition,
+                MiddlewareInterface::class
+            );
+        }
+
+        if (DefinitionHelper::isStringNotClassName($this->definition)) {
+            return sprintf(
+                'Class `%s` not found. It may be needed to install a package with this middleware.',
+                $this->definition
+            );
+        }
+
+        if (is_array($this->definition)) {
+            try {
+                DefinitionValidator::validateArrayDefinition($this->definition);
+            } catch (InvalidConfigException $e) {
+                return <<<SOLUTION
+                You may have an error in array definition. Array definition validation result:
+
+                ```
+                {$e->getMessage()}
+                ```
+                SOLUTION;
+            }
+
+            /** @psalm-suppress MixedArgument In valid array definition element "class" always is string */
+            return sprintf(
+                'Array definition is valid, class `%s` exists, but does not implement `%s`.',
+                $this->definition['class'],
+                MiddlewareInterface::class
+            );
+        }
+
+        return null;
+    }
+}
diff --git a/src/Exception/InvalidMiddlewareReturnTypeException.php b/src/Exception/InvalidMiddlewareReturnTypeException.php
new file mode 100644
index 0000000..c4a463b
--- /dev/null
+++ b/src/Exception/InvalidMiddlewareReturnTypeException.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Middleware\Dispatcher\Exception;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Throwable;
+use Yiisoft\Middleware\Dispatcher\Helper\DefinitionHelper;
+use Yiisoft\Middleware\Dispatcher\Helper\ResponseHelper;
+
+final class InvalidMiddlewareReturnTypeException extends AbstractInvalidMiddlewareException
+{
+    public function __construct(
+        mixed $definition,
+        private readonly mixed $result,
+        ?Throwable $previous = null,
+    ) {
+        $this->definitionString = DefinitionHelper::convertDefinitionToString($definition);
+
+        parent::__construct(
+            $definition,
+            sprintf(
+                'Middleware %s must return an instance of `%s` or `%s`, %s returned.',
+                $this->definitionString,
+                MiddlewareInterface::class,
+                ResponseInterface::class,
+                ResponseHelper::convertToString($this->result),
+            ),
+            $previous,
+        );
+    }
+
+    public function getName(): string
+    {
+        return sprintf('Invalid middleware result type %s', get_debug_type($this->result));
+    }
+}
diff --git a/src/Helper/DefinitionHelper.php b/src/Helper/DefinitionHelper.php
new file mode 100644
index 0000000..ed82ebb
--- /dev/null
+++ b/src/Helper/DefinitionHelper.php
@@ -0,0 +1,94 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Middleware\Dispatcher\Helper;
+
+use function array_slice;
+use function count;
+use function gettype;
+use function is_array;
+use function is_bool;
+use function is_float;
+use function is_int;
+use function is_object;
+use function is_string;
+
+final class DefinitionHelper
+{
+    /**
+     * @psalm-assert-if-true string $definition
+     */
+    public static function isStringNotClassName(mixed $definition): bool
+    {
+        return is_string($definition)
+            && !class_exists($definition);
+    }
+
+    /**
+     * @psalm-assert-if-true class-string $definition
+     */
+    public static function isNotMiddlewareClassName(mixed $definition): bool
+    {
+        return is_string($definition)
+            && class_exists($definition);
+    }
+
+    /**
+     * @psalm-assert-if-true array{0:class-string,1:string} $definition
+     */
+    public static function isControllerWithNonExistAction(mixed $definition): bool
+    {
+        return is_array($definition)
+            && array_keys($definition) === [0, 1]
+            && is_string($definition[0])
+            && class_exists($definition[0]);
+    }
+
+    public static function convertDefinitionToString(mixed $middlewareDefinition): string
+    {
+        if (is_object($middlewareDefinition)) {
+            return 'an instance of `' . $middlewareDefinition::class . '`';
+        }
+
+        if (is_string($middlewareDefinition)) {
+            return '"' . $middlewareDefinition . '"';
+        }
+
+        if (is_array($middlewareDefinition)) {
+            $items = [];
+            /** @var mixed $value */
+            foreach (array_slice($middlewareDefinition, 0, 2) as $key => $value) {
+                $items[] = (is_string($key) ? '"' . $key . '" => ' : '') . self::convertToString($value);
+            }
+            return '[' . implode(', ', $items) . (count($middlewareDefinition) > 2 ? ', ...' : '') . ']';
+        }
+
+        return self::convertToString($middlewareDefinition);
+    }
+
+    private static function convertToString(mixed $value): string
+    {
+        if (is_string($value)) {
+            return '"' . $value . '"';
+        }
+
+        if (is_int($value) || is_float($value)) {
+            return (string) $value;
+        }
+
+        if (is_bool($value)) {
+            return $value ? 'true' : 'false';
+        }
+
+        if ($value === null) {
+            return '"null"';
+        }
+
+        if (is_object($value)) {
+            return sprintf('"%s"', $value::class);
+        }
+
+        return sprintf('"%s"', gettype($value));
+    }
+}
diff --git a/src/Helper/ResponseHelper.php b/src/Helper/ResponseHelper.php
new file mode 100644
index 0000000..9f72bee
--- /dev/null
+++ b/src/Helper/ResponseHelper.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Middleware\Dispatcher\Helper;
+
+use function gettype;
+use function is_array;
+use function is_bool;
+use function is_object;
+
+final class ResponseHelper
+{
+    public static function convertToString(mixed $response): string
+    {
+        if (is_object($response)) {
+            return sprintf('"%s" (object)', $response::class);
+        }
+
+        if (is_array($response)) {
+            $items = [];
+
+            if (!array_is_list($response)) {
+                /** @var mixed $value */
+                foreach (array_keys($response) as $key) {
+                    $items[] = sprintf('"%s" => ...', $key);
+                }
+            } else {
+                $items[] = '...';
+            }
+            return sprintf(
+                '"[%s]" (array of %d%s)',
+                implode(', ', $items),
+                $count = count($response),
+                $count === 1 ? ' element' : ' elements'
+            );
+        }
+
+        if (is_bool($response)) {
+            return sprintf('"%s" (bool)', $response ? 'true' : 'false');
+        }
+
+        if (is_scalar($response)) {
+            return sprintf(
+                '"%s" (%s)',
+                (string)$response,
+                match (true) {
+                    is_int($response) => 'int',
+                    is_float($response) => 'float',
+                    default => gettype($response)
+                }
+            );
+        }
+
+        return sprintf('"%s" (%s)', gettype($response), get_debug_type($response));
+    }
+}
diff --git a/src/InvalidMiddlewareDefinitionException.php b/src/InvalidMiddlewareDefinitionException.php
index 48280cf..5cca7fd 100644
--- a/src/InvalidMiddlewareDefinitionException.php
+++ b/src/InvalidMiddlewareDefinitionException.php
@@ -4,33 +4,25 @@
 
 namespace Yiisoft\Middleware\Dispatcher;
 
-use InvalidArgumentException;
-use Psr\Http\Server\MiddlewareInterface;
-use Yiisoft\Definitions\Exception\InvalidConfigException;
-use Yiisoft\Definitions\Helpers\DefinitionValidator;
-use Yiisoft\FriendlyException\FriendlyExceptionInterface;
+use Throwable;
+use Yiisoft\Middleware\Dispatcher\Exception\AbstractInvalidMiddlewareException;
+use Yiisoft\Middleware\Dispatcher\Helper\DefinitionHelper;
 
-use function array_slice;
-use function count;
-use function gettype;
-use function is_array;
-use function is_bool;
-use function is_float;
-use function is_int;
-use function is_object;
-use function is_string;
-
-final class InvalidMiddlewareDefinitionException extends InvalidArgumentException implements FriendlyExceptionInterface
+final class InvalidMiddlewareDefinitionException extends AbstractInvalidMiddlewareException
 {
-    private readonly string $definitionString;
-
     public function __construct(
-        private mixed $definition
+        mixed $definition,
+        ?Throwable $previous = null,
     ) {
-        $this->definitionString = $this->convertDefinitionToString($definition);
+        $this->definitionString = DefinitionHelper::convertDefinitionToString($definition);
 
         parent::__construct(
-            'Parameter should be either PSR middleware class name or a callable. Got ' . $this->definitionString . '.'
+            $definition,
+            sprintf(
+                'Parameter should be either PSR middleware class name or a callable. Got %s.',
+                $this->definitionString,
+            ),
+            $previous,
         );
     }
 
@@ -38,203 +30,4 @@ public function getName(): string
     {
         return 'Invalid middleware definition';
     }
-
-    public function getSolution(): ?string
-    {
-        $solution = [
-            <<<SOLUTION
-            ## Got definition value
-
-            `{$this->definitionString}`
-            SOLUTION
-        ];
-
-        $suggestion = $this->generateSuggestion();
-        if ($suggestion !== null) {
-            $solution[] = '## Suggestion';
-            $solution[] = $suggestion;
-        }
-
-        $solution[] = <<<SOLUTION
-        ## Middleware definition examples
-
-        PSR middleware class name:
-
-        ```php
-        Yiisoft\Session\SessionMiddleware::class
-        ```
-
-        PSR middleware array definition:
-
-        ```php
-        [
-            'class' => MyMiddleware::class,
-            '__construct()' => [
-                'someVar' => 42,
-            ],
-        ]
-        ```
-
-        Closure that returns `ResponseInterface`:
-
-        ```php
-        static function (): ResponseInterface {
-            return new Response(418);
-        },
-        ```
-
-        Closure that returns `MiddlewareInterface`:
-
-        ```php
-        static function (): MiddlewareInterface {
-            return new TestMiddleware();
-        }
-        ```
-
-        Action in controller:
-
-        ```php
-        [App\Backend\UserController::class, 'index']
-        ```
-
-        ## Related links
-
-        - [Array definition syntax](https://github.com/yiisoft/definitions#arraydefinition)
-        - [Callable PHP documentation](https://www.php.net/manual/language.types.callable.php)
-        SOLUTION;
-
-        return implode("\n\n", $solution);
-    }
-
-    private function generateSuggestion(): ?string
-    {
-        if ($this->isControllerWithNonExistAction()) {
-            return <<<SOLUTION
-            Class `{$this->definition[0]}` exists, but does not contain method `{$this->definition[1]}()`.
-
-            Try adding `{$this->definition[1]}()` action to `{$this->definition[0]}` controller:
-
-            ```php
-            public function {$this->definition[1]}(): ResponseInterface
-            {
-                // TODO: Implement your action
-            }
-            ```
-            SOLUTION;
-        }
-
-        if ($this->isNotMiddlewareClassName()) {
-            return sprintf(
-                'Class `%s` exists, but does not implement `%s`.',
-                $this->definition,
-                MiddlewareInterface::class
-            );
-        }
-
-        if ($this->isStringNotClassName()) {
-            return sprintf(
-                'Class `%s` not found. It may be needed to install a package with this middleware.',
-                $this->definition
-            );
-        }
-
-        if (is_array($this->definition)) {
-            try {
-                DefinitionValidator::validateArrayDefinition($this->definition);
-            } catch (InvalidConfigException $e) {
-                return <<<SOLUTION
-                You may have an error in array definition. Array definition validation result:
-
-                ```
-                {$e->getMessage()}
-                ```
-                SOLUTION;
-            }
-
-            /** @psalm-suppress MixedArgument In valid array definition element "class" always is string */
-            return sprintf(
-                'Array definition is valid, class `%s` exists, but does not implement `%s`.',
-                $this->definition['class'],
-                MiddlewareInterface::class
-            );
-        }
-
-        return null;
-    }
-
-    /**
-     * @psalm-assert-if-true string $this->definition
-     */
-    private function isStringNotClassName(): bool
-    {
-        return is_string($this->definition)
-            && !class_exists($this->definition);
-    }
-
-    /**
-     * @psalm-assert-if-true class-string $this->definition
-     */
-    private function isNotMiddlewareClassName(): bool
-    {
-        return is_string($this->definition)
-            && class_exists($this->definition);
-    }
-
-    /**
-     * @psalm-assert-if-true array{0:class-string,1:string} $this->definition
-     */
-    private function isControllerWithNonExistAction(): bool
-    {
-        return is_array($this->definition)
-            && array_keys($this->definition) === [0, 1]
-            && is_string($this->definition[0])
-            && class_exists($this->definition[0]);
-    }
-
-    private function convertDefinitionToString(mixed $middlewareDefinition): string
-    {
-        if (is_object($middlewareDefinition)) {
-            return 'an instance of "' . $middlewareDefinition::class . '"';
-        }
-
-        if (is_string($middlewareDefinition)) {
-            return '"' . $middlewareDefinition . '"';
-        }
-
-        if (is_array($middlewareDefinition)) {
-            $items = [];
-            /** @var mixed $value */
-            foreach (array_slice($middlewareDefinition, 0, 2) as $key => $value) {
-                $items[] = (is_string($key) ? '"' . $key . '" => ' : '') . $this->convertToString($value);
-            }
-            return '[' . implode(', ', $items) . (count($middlewareDefinition) > 2 ? ', ...' : '') . ']';
-        }
-
-        return $this->convertToString($middlewareDefinition);
-    }
-
-    private function convertToString(mixed $value): string
-    {
-        if (is_string($value)) {
-            return '"' . $value . '"';
-        }
-
-        if (is_int($value) || is_float($value)) {
-            return (string) $value;
-        }
-
-        if (is_bool($value)) {
-            return $value ? 'true' : 'false';
-        }
-
-        if ($value === null) {
-            return 'null';
-        }
-
-        if (is_object($value)) {
-            return $value::class;
-        }
-
-        return gettype($value);
-    }
 }
diff --git a/src/MiddlewareFactory.php b/src/MiddlewareFactory.php
index e9df36a..258e7a4 100644
--- a/src/MiddlewareFactory.php
+++ b/src/MiddlewareFactory.php
@@ -17,6 +17,7 @@
 use Yiisoft\Definitions\Exception\InvalidConfigException;
 use Yiisoft\Definitions\Helpers\DefinitionValidator;
 use Yiisoft\Injector\Injector;
+use Yiisoft\Middleware\Dispatcher\Exception\InvalidMiddlewareReturnTypeException;
 
 use function in_array;
 use function is_array;
@@ -216,7 +217,7 @@ public function process(
                     return $response->process($request, $handler);
                 }
 
-                throw new InvalidMiddlewareDefinitionException($this->callback);
+                throw new InvalidMiddlewareReturnTypeException($this->callback, $response);
             }
 
             public function __debugInfo(): array
@@ -273,7 +274,7 @@ public function process(
                     return $response;
                 }
 
-                throw new InvalidMiddlewareDefinitionException([$this->class, $this->method]);
+                throw new InvalidMiddlewareReturnTypeException([$this->class, $this->method], $response);
             }
 
             public function __debugInfo()
diff --git a/tests/Exception/AbstractInvalidMiddlewareExceptionTest.php b/tests/Exception/AbstractInvalidMiddlewareExceptionTest.php
new file mode 100644
index 0000000..490dda2
--- /dev/null
+++ b/tests/Exception/AbstractInvalidMiddlewareExceptionTest.php
@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Middleware\Dispatcher\Tests\Exception;
+
+use PHPUnit\Framework\TestCase;
+use Throwable;
+use Yiisoft\Middleware\Dispatcher\Tests\Support\TestController;
+
+abstract class AbstractInvalidMiddlewareExceptionTest extends TestCase
+{
+    public function dataSolution(): array
+    {
+        return [
+            [
+                'test',
+                'Class `test` not found',
+            ],
+            [
+                TestController::class,
+                'Class `Yiisoft\Middleware\Dispatcher\Tests\Support\TestController` exists, but does not implement',
+            ],
+            [
+                new TestController(),
+                'Related links',
+            ],
+            [
+                [TestController::class, 'notExistsAction'],
+                'Try adding `notExistsAction()` action to ' .
+                '`Yiisoft\Middleware\Dispatcher\Tests\Support\TestController` controller:',
+            ],
+            [
+                ['object' => TestController::class, 'index'],
+                'You may have an error in array definition. Array definition validation result',
+            ],
+            [
+                ['class' => TestController::class],
+                'Array definition is valid, ' .
+                'class `Yiisoft\Middleware\Dispatcher\Tests\Support\TestController` exists, ' .
+                'but does not implement `Psr\Http\Server\MiddlewareInterface`.',
+            ],
+        ];
+    }
+
+    /**
+     * @dataProvider dataSolution
+     */
+    public function testSolution(mixed $definition, string $expectedSolution): void
+    {
+        $exception = static::createException($definition);
+        self::assertStringContainsString($expectedSolution, $exception->getSolution());
+    }
+
+    abstract protected function createException(mixed $definition): Throwable;
+}
diff --git a/tests/Exception/InvalidMiddlewareDefinitionExceptionTest.php b/tests/Exception/InvalidMiddlewareDefinitionExceptionTest.php
new file mode 100644
index 0000000..d4c642a
--- /dev/null
+++ b/tests/Exception/InvalidMiddlewareDefinitionExceptionTest.php
@@ -0,0 +1,70 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Middleware\Dispatcher\Tests\Exception;
+
+use Throwable;
+use Yiisoft\Middleware\Dispatcher\InvalidMiddlewareDefinitionException;
+use Yiisoft\Middleware\Dispatcher\Tests\Support\TestController;
+
+final class InvalidMiddlewareDefinitionExceptionTest extends AbstractInvalidMiddlewareExceptionTest
+{
+    public function dataExceptionMessage(): array
+    {
+        return [
+            [
+                'test',
+                '"test"',
+            ],
+            [
+                TestController::class,
+                '"Yiisoft\Middleware\Dispatcher\Tests\Support\TestController"',
+            ],
+            [
+                new TestController(),
+                'an instance of `Yiisoft\Middleware\Dispatcher\Tests\Support\TestController`',
+            ],
+            [
+                [TestController::class, 'notExistsAction'],
+                '["Yiisoft\Middleware\Dispatcher\Tests\Support\TestController", "notExistsAction"]',
+            ],
+            [
+                ['class' => TestController::class, 'index'],
+                '["class" => "Yiisoft\Middleware\Dispatcher\Tests\Support\TestController", "index"]',
+            ],
+            [
+                ['object' => TestController::class, 'index'],
+                '["object" => "Yiisoft\Middleware\Dispatcher\Tests\Support\TestController", "index"]',
+            ],
+            [
+                ['class' => TestController::class],
+                '["class" => "Yiisoft\Middleware\Dispatcher\Tests\Support\TestController"]',
+            ],
+        ];
+    }
+
+    /**
+     * @dataProvider dataExceptionMessage
+     */
+    public function testExceptionMessage(mixed $definition, string $expectedMessage): void
+    {
+        $exception = self::createException($definition);
+        self::assertStringEndsWith('. Got ' . $expectedMessage . '.', $exception->getMessage());
+    }
+
+    public function testName(): void
+    {
+        $exception = new InvalidMiddlewareDefinitionException('test');
+
+        self::assertSame(
+            'Invalid middleware definition',
+            $exception->getName()
+        );
+    }
+
+    protected function createException(mixed $definition): Throwable
+    {
+        return new InvalidMiddlewareDefinitionException($definition);
+    }
+}
diff --git a/tests/Exception/InvalidMiddlewareReturnTypeExceptionTest.php b/tests/Exception/InvalidMiddlewareReturnTypeExceptionTest.php
new file mode 100644
index 0000000..2bfce43
--- /dev/null
+++ b/tests/Exception/InvalidMiddlewareReturnTypeExceptionTest.php
@@ -0,0 +1,124 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Middleware\Dispatcher\Tests\Exception;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use stdClass;
+use Throwable;
+use Yiisoft\Middleware\Dispatcher\Exception\InvalidMiddlewareReturnTypeException;
+
+final class InvalidMiddlewareReturnTypeExceptionTest extends AbstractInvalidMiddlewareExceptionTest
+{
+    public function dataInvalidReturnType(): array
+    {
+        return [
+            [
+                'Middleware "null"',
+                null,
+                'null',
+            ],
+            [
+                'Middleware ["key1" => "null"]',
+                ['key1' => null],
+                'null',
+            ],
+            [
+                'Middleware ["key1" => "stdClass"]',
+                ['key1' => new stdClass()],
+                'null',
+            ],
+            [
+                'Middleware ["key1" => true, "key2" => false]',
+                ['key1' => true, 'key2' => false],
+                'null',
+            ],
+            [
+                'Middleware ["key1" => "null", "key2" => "null", ...]',
+                ['key1' => null, 'key2' => null, 'key3' => null],
+                'null',
+            ],
+            [
+                'Middleware ["key" => "null"]',
+                ['key' => null],
+                'null',
+            ],
+            [
+                'Middleware "resource"',
+                fopen('php://memory', 'r'),
+                'null',
+            ],
+            [
+                'Middleware an instance of `Closure`',
+                fn() => 42,
+                42,
+            ],
+            [
+                'Middleware an instance of `Closure`',
+                fn() => [new stdClass()],
+                new stdClass(),
+            ],
+            [
+                'Middleware an instance of `Closure`',
+                fn() => true,
+                true,
+            ],
+            [
+                'Middleware an instance of `Closure`',
+                fn() => false,
+                false,
+            ],
+            [
+                'Middleware an instance of `Closure`',
+                fn() => ['class' => null, 'setValue()' => [42], 'prepare()' => []],
+                ['class' => null, 'setValue()' => [42], 'prepare()' => []],
+            ],
+        ];
+    }
+
+    /**
+     * @dataProvider dataInvalidReturnType
+     */
+    public function testUnknownDefinition(string $startMessage, mixed $definition, mixed $result): void
+    {
+        $exception = new InvalidMiddlewareReturnTypeException($definition, null);
+        self::assertStringStartsWith(
+            sprintf(
+                '%s must return an instance of `%s` or `%s`',
+                $startMessage,
+                MiddlewareInterface::class,
+                ResponseInterface::class,
+            ),
+            $exception->getMessage()
+        );
+    }
+
+    public static function dataProviderName(): iterable
+    {
+        yield 'null' => [null];
+        yield 'string' => ['test'];
+        yield 'array' => [[]];
+        yield 'object' => [new stdClass()];
+        yield 'int' => [42];
+    }
+
+    /**
+     * @dataProvider dataProviderName
+     */
+    public function testName(mixed $result): void
+    {
+        $exception = new InvalidMiddlewareReturnTypeException('test', $result);
+
+        self::assertSame(
+            sprintf('Invalid middleware result type %s', get_debug_type($result)),
+            $exception->getName()
+        );
+    }
+
+    protected function createException(mixed $definition): Throwable
+    {
+        return new InvalidMiddlewareReturnTypeException($definition, new stdClass());
+    }
+}
diff --git a/tests/Helper/ResponseHelperTest.php b/tests/Helper/ResponseHelperTest.php
new file mode 100644
index 0000000..daa3776
--- /dev/null
+++ b/tests/Helper/ResponseHelperTest.php
@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Middleware\Dispatcher\Tests\Helper;
+
+use PHPUnit\Framework\TestCase;
+use stdClass;
+use Yiisoft\Middleware\Dispatcher\Helper\ResponseHelper;
+
+final class ResponseHelperTest extends TestCase
+{
+    public static function dataResult(): iterable
+    {
+        yield 'array 2' => [
+            ['error' => true, 'message' => 'Error'],
+            '"["error" => ..., "message" => ...]" (array of 2 elements)',
+        ];
+        yield 'array 1' => [
+            [true],
+            '"[...]" (array of 1 element)',
+        ];
+        yield 'string' => [
+            'ok',
+            '"ok" (string)',
+        ];
+        yield 'int' => [
+            555,
+            '"555" (int)',
+        ];
+        yield 'float' => [
+            555.44,
+            '"555.44" (float)',
+        ];
+        yield 'double' => [
+            555.444444343434343434343434343434343,
+            '"555.44444434343" (float)',
+        ];
+        yield 'bool true' => [
+            true,
+            '"true" (bool)',
+        ];
+        yield 'bool false' => [
+            false,
+            '"false" (bool)',
+        ];
+        yield 'stdClass' => [
+            new stdClass(),
+            '"stdClass" (object)',
+        ];
+    }
+
+    /**
+     * @dataProvider dataResult
+     */
+    public function testResult(mixed $result, string $expected): void
+    {
+        $this->assertSame($expected, ResponseHelper::convertToString($result));
+    }
+}
diff --git a/tests/InvalidMiddlewareDefinitionExceptionTest.php b/tests/InvalidMiddlewareDefinitionExceptionTest.php
deleted file mode 100644
index e6cfa6d..0000000
--- a/tests/InvalidMiddlewareDefinitionExceptionTest.php
+++ /dev/null
@@ -1,105 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Yiisoft\Middleware\Dispatcher\Tests;
-
-use PHPUnit\Framework\TestCase;
-use stdClass;
-use Yiisoft\Middleware\Dispatcher\InvalidMiddlewareDefinitionException;
-use Yiisoft\Middleware\Dispatcher\Tests\Support\TestController;
-
-final class InvalidMiddlewareDefinitionExceptionTest extends TestCase
-{
-    public function dataBase(): array
-    {
-        return [
-            [
-                'test',
-                '"test"',
-                'Class `test` not found',
-            ],
-            [
-                TestController::class,
-                '"Yiisoft\Middleware\Dispatcher\Tests\Support\TestController"',
-                'Class `Yiisoft\Middleware\Dispatcher\Tests\Support\TestController` exists, but does not implement',
-            ],
-            [
-                new TestController(),
-                'an instance of "Yiisoft\Middleware\Dispatcher\Tests\Support\TestController"',
-                'Related links',
-            ],
-            [
-                [TestController::class, 'notExistsAction'],
-                '["Yiisoft\Middleware\Dispatcher\Tests\Support\TestController", "notExistsAction"]',
-                'Try adding `notExistsAction()` action to ' .
-                '`Yiisoft\Middleware\Dispatcher\Tests\Support\TestController` controller:',
-            ],
-            [
-                ['class' => TestController::class, 'index'],
-                '["class" => "Yiisoft\Middleware\Dispatcher\Tests\Support\TestController", "index"]',
-                null,
-            ],
-            [
-                ['object' => TestController::class, 'index'],
-                '["object" => "Yiisoft\Middleware\Dispatcher\Tests\Support\TestController", "index"]',
-                'You may have an error in array definition. Array definition validation result',
-            ],
-            [
-                ['class' => TestController::class],
-                '["class" => "Yiisoft\Middleware\Dispatcher\Tests\Support\TestController"]',
-                'Array definition is valid, ' .
-                'class `Yiisoft\Middleware\Dispatcher\Tests\Support\TestController` exists, ' .
-                'but does not implement `Psr\Http\Server\MiddlewareInterface`.',
-            ],
-        ];
-    }
-
-    /**
-     * @dataProvider dataBase
-     */
-    public function testBase(mixed $definition, string $expectedMessage, ?string $expectedSolution): void
-    {
-        $exception = new InvalidMiddlewareDefinitionException($definition);
-        self::assertStringEndsWith('. Got ' . $expectedMessage . '.', $exception->getMessage());
-        if ($expectedSolution !== null) {
-            self::assertStringContainsString($expectedSolution, $exception->getSolution());
-        }
-    }
-
-    public function dataUnknownDefinition(): array
-    {
-        return [
-            [42, '42'],
-            [[new stdClass()], '[stdClass]'],
-            [true, 'true'],
-            [false, 'false'],
-            [
-                ['class' => null, 'setValue()' => [42], 'prepare()' => []],
-                '["class" => null, "setValue()" => array, ...]',
-            ],
-        ];
-    }
-
-    /**
-     * @dataProvider dataUnknownDefinition
-     */
-    public function testUnknownDefinition(mixed $definition, string $value): void
-    {
-        $exception = new InvalidMiddlewareDefinitionException($definition);
-        self::assertSame(
-            'Parameter should be either PSR middleware class name or a callable. Got ' . $value . '.',
-            $exception->getMessage()
-        );
-    }
-
-    public function testName(): void
-    {
-        $exception = new InvalidMiddlewareDefinitionException('test');
-
-        self::assertSame(
-            'Invalid middleware definition',
-            $exception->getName()
-        );
-    }
-}
diff --git a/tests/MiddlewareFactoryTest.php b/tests/MiddlewareFactoryTest.php
index dd8515a..7949232 100644
--- a/tests/MiddlewareFactoryTest.php
+++ b/tests/MiddlewareFactoryTest.php
@@ -12,6 +12,7 @@
 use Psr\Http\Message\ServerRequestInterface;
 use Psr\Http\Server\MiddlewareInterface;
 use Psr\Http\Server\RequestHandlerInterface;
+use Yiisoft\Middleware\Dispatcher\Exception\InvalidMiddlewareReturnTypeException;
 use Yiisoft\Middleware\Dispatcher\InvalidMiddlewareDefinitionException;
 use Yiisoft\Middleware\Dispatcher\MiddlewareFactory;
 use Yiisoft\Middleware\Dispatcher\ParametersResolverInterface;
@@ -253,7 +254,12 @@ public function testInvalidMiddlewareWithWrongCallable(): void
                 static fn() => 42
             );
 
-        $this->expectException(InvalidMiddlewareDefinitionException::class);
+        $this->expectException(InvalidMiddlewareReturnTypeException::class);
+        $this->expectExceptionMessage(sprintf(
+            'Middleware an instance of `Closure` must return an instance of `%s` or `%s`, "42" (int) returned.',
+            MiddlewareInterface::class,
+            ResponseInterface::class,
+        ));
         $middleware->process(
             $this->createMock(ServerRequestInterface::class),
             $this->createMock(RequestHandlerInterface::class)
@@ -284,7 +290,12 @@ public function testInvalidMiddlewareWithWrongController(): void
             ->getMiddlewareFactory($container)
             ->create([InvalidController::class, 'index']);
 
-        $this->expectException(InvalidMiddlewareDefinitionException::class);
+        $this->expectException(InvalidMiddlewareReturnTypeException::class);
+        $this->expectExceptionMessage(sprintf(
+            'Middleware ["Yiisoft\Middleware\Dispatcher\Tests\Support\InvalidController", "index"] must return an instance of `%s` or `%s`, "200" (int) returned.',
+            MiddlewareInterface::class,
+            ResponseInterface::class,
+        ));
         $middleware->process(
             $this->createMock(ServerRequestInterface::class),
             $this->createMock(RequestHandlerInterface::class)