diff --git a/src/Bot/HttpClient.php b/src/Bot/HttpClient.php
index 2f5073a..616fd4e 100644
--- a/src/Bot/HttpClient.php
+++ b/src/Bot/HttpClient.php
@@ -166,7 +166,7 @@ class HttpClient
          * therefore they are not handled as exceptions
          */
         if (in_array($statusCode, [403, 404, 500])) {
-            throw new \Exception($errorMessage);
+            throw new \InvalidArgumentException($errorMessage);
         }
 
         if ($statusCode == 503) {
@@ -213,7 +213,7 @@ class HttpClient
             $errors = $validator->validate($class);
         }
 
-        if ($errors->count() > 0) {
+        if ((is_object($errors) && $errors->count() > 0) || is_string($errors)) {
             $message = (string) $errors;
             throw new InvalidArgumentException($message);
         }
diff --git a/src/Bot/Model/Request/CommandEditRequest.php b/src/Bot/Model/Request/CommandEditRequest.php
index fe41cc5..98775e1 100644
--- a/src/Bot/Model/Request/CommandEditRequest.php
+++ b/src/Bot/Model/Request/CommandEditRequest.php
@@ -59,4 +59,11 @@ class CommandEditRequest extends LazyJsonMapper
         'name' => 'string',
         'description' => 'string'
     ];
+
+    public function validate()
+    {
+        if (empty($this->getName())) {
+            return 'Empty name';
+        }
+    }
 }
diff --git a/src/Bot/Model/Response/CommonFields.php b/src/Bot/Model/Response/CommonFields.php
index 63e2002..de38933 100644
--- a/src/Bot/Model/Response/CommonFields.php
+++ b/src/Bot/Model/Response/CommonFields.php
@@ -58,6 +58,6 @@ class CommonFields extends LazyJsonMapper
      */
     public function isError()
     {
-        return !empty($this->getErrors());
+        return (bool) !empty($this->getErrors());
     }
 }
\ No newline at end of file
diff --git a/tests/Bot/Tests/CommandsTest.php b/tests/Bot/Tests/CommandsTest.php
index db3c6d3..acafd7c 100644
--- a/tests/Bot/Tests/CommandsTest.php
+++ b/tests/Bot/Tests/CommandsTest.php
@@ -15,7 +15,9 @@ namespace RetailCrm\Mg\Bot\Tests;
 
 use Exception;
 use InvalidArgumentException;
+use RetailCrm\Common\Exception\InvalidJsonException;
 use RetailCrm\Mg\Bot\Model\Request\CommandEditRequest;
+use RetailCrm\Mg\Bot\Model\Response\ErrorOnlyResponse;
 use RetailCrm\Mg\Bot\Test\TestCase;
 
 /**
@@ -38,7 +40,12 @@ class CommandsTest extends TestCase
     {
         self::expectException(InvalidArgumentException::class);
 
-        $client = self::getApiClient();
+        $client = self::getApiClient(
+            null,
+            null,
+            false,
+            $this->getResponse('EOF',400)
+        );
 
         $request = new CommandEditRequest();
         $request->setDescription("qwerty");
@@ -67,7 +74,12 @@ class CommandsTest extends TestCase
      */
     public function testCommandEdit()
     {
-        $client = self::getApiClient();
+        $client = self::getApiClient(
+            null,
+            null,
+            false,
+            $this->getJsonResponse('commandEdit')
+        );
 
         $request = new CommandEditRequest();
         $request->setBotId(1);
@@ -76,7 +88,8 @@ class CommandsTest extends TestCase
 
         $response = $client->commandEdit($request);
 
-        self::assertTrue($response->isSuccessful() == true);
+        self::assertTrue($response instanceof ErrorOnlyResponse);
+        self::assertTrue(!$response->isError());
     }
 
     /**
@@ -86,10 +99,15 @@ class CommandsTest extends TestCase
      */
     public function testCommandDelete()
     {
-        $client = self::getApiClient();
+        $client = self::getApiClient(
+            null,
+            null,
+            false,
+            $this->getJsonResponse('commandEdit')
+        );
 
         $response = $client->commandDelete("show_payment_types");
 
-        self::assertTrue($response->isSuccessful() == true);
+        self::assertTrue($response->isError() == false);
     }
 }
diff --git a/tests/Bot/Tests/MessagesTest.php b/tests/Bot/Tests/MessagesTest.php
index a46b0d5..72c33c9 100644
--- a/tests/Bot/Tests/MessagesTest.php
+++ b/tests/Bot/Tests/MessagesTest.php
@@ -35,15 +35,24 @@ class MessagesTest extends TestCase
      */
     public function testMessageSend()
     {
-        $client = self::getApiClient();
+        $client = self::getApiClient(
+            null,
+            null,
+            false,
+            $this->getResponse(
+                '{"errors":["chat_id is a required field"]}',
+                400
+            )
+        );
 
         $request = new MessageSendRequest();
         $request->setChatId(0);
         $request->setScope(Constants::MESSAGE_SCOPE_PUBLIC);
         $request->setContent("Hello");
 
-        $request = $client->messageSend($request);
+        $response = $client->messageSend($request);
 
-        self::assertEquals($request->getStatusCode(), 400);
+        self::assertTrue($response->isError());
+        self::assertEquals(1, count($response->getErrors()));
     }
 }
diff --git a/tests/Resources/commandEdit.json b/tests/Resources/commandEdit.json
new file mode 100644
index 0000000..6f28ef9
--- /dev/null
+++ b/tests/Resources/commandEdit.json
@@ -0,0 +1 @@
+{"id":6,"name":"show_payment_types","description":"Get available payment types","created_at":"2019-06-19T09:02:35Z","updated_at":"2019-06-19T09:39:00Z"}
\ No newline at end of file