Add exception when merging same user ids (RAD-907)

CHANGELOG.md

@@ -5,6 +5,8 @@
 <!-- There is always Unreleased section on the top. Subsections (Added, Changed, Fixed, Removed) should be added as needed. -->
 
 ## Unreleased
+### Fixed
+- Check for equality of user ids in `UserMerge` - so that we don't "merge" user into the same user id effectively deleting it.
 
 ## 1.3.0 - 2018-01-19
 ### Changed

src/Model/Command/UserMerge.php

@@ -19,6 +19,8 @@ private function __construct(string $targetUserId, string $sourceUserId)
     {
         $this->setTargetUserId($targetUserId);
         $this->setSourceUserId($sourceUserId);
+
+        $this->assertUserIdsNotEqual();
     }
 
     /**
@@ -65,6 +67,15 @@ protected function setTargetUserId(string $targetUserId): void
         $this->targetUserId = $targetUserId;
     }
 
+    private function assertUserIdsNotEqual(): void
+    {
+        Assertion::notEq(
+            $this->sourceUserId,
+            $this->targetUserId,
+            'You have to provide different source and target user id in UserMerge ("%s" set for both)'
+        );
+    }
+
     protected function getCommandType(): string
     {
         return 'user-merge';
@@ -77,4 +88,11 @@ protected function getCommandParameters(): array
             'source_user_id' => $this->sourceUserId,
         ];
     }
+
+    public function jsonSerialize(): array
+    {
+        $this->assertUserIdsNotEqual();
+
+        return parent::jsonSerialize();
+    }
 }

tests/unit/Model/Command/UserMergeTest.php

@@ -2,6 +2,7 @@
 
 namespace Lmc\Matej\Model\Command;
 
+use Assert\InvalidArgumentException;
 use Lmc\Matej\UnitTestCase;
 
 class UserMergeTest extends UnitTestCase
@@ -19,6 +20,14 @@ public function shouldGenerateCorrectSignature(): void
         $this->assertUserMergeCommand($command, $sourceUserId, $targetUserId);
     }
 
+    public function shouldThrowExceptionWhenMergingSameUsers(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('You have to provide different source and target user id in UserMerge ("test-user" set for both)');
+
+        UserMerge::mergeInto('test-user', 'test-user');
+    }
+
     /**
      * Execute asserts against user merge command
      * @param UserMerge $command