MAGETWO-31785: Exception in customerGroups/search API when send request using GET method without search creteria

- Added assertion for HTTP error code

Author: anupdugar

dev/tests/api-functional/testsuite/Magento/Webapi/DeserializationTest.php

@@ -42,6 +42,7 @@ public function testPostRequestWithEmptyBody()
         try {
             $this->_webApiCall($serviceInfo, CurlClient::EMPTY_REQUEST_BODY);
         } catch (\Exception $e) {
+            $this->assertEquals(\Magento\Webapi\Exception::HTTP_BAD_REQUEST, $e->getCode());
             $this->assertContains(
                 $expectedMessage,
                 $e->getMessage(),
@@ -67,6 +68,7 @@ public function testPutRequestWithEmptyBody()
         try {
             $this->_webApiCall($serviceInfo, CurlClient::EMPTY_REQUEST_BODY);
         } catch (\Exception $e) {
+            $this->assertEquals(\Magento\Webapi\Exception::HTTP_BAD_REQUEST, $e->getCode());
             $this->assertContains(
                 $expectedMessage,
                 $e->getMessage(),