Relationships Links can be an object with href link

refs #57

Author: Art4

src/V1/RelationshipLink.php

@@ -60,11 +60,11 @@ protected function parse($object)
         $links = get_object_vars($object);
 
         if (array_key_exists('self', $links)) {
-            if (! is_string($links['self'])) {
-                throw new ValidationException('property "self" has to be a string, "' . gettype($links['self']) . '" given.');
+            if (! is_string($links['self']) and ! is_object($links['self'])) {
+                throw new ValidationException('property "self" has to be a string or object, "' . gettype($links['self']) . '" given.');
             }
 
-            $this->set('self', strval($links['self']));
+            $this->setLink('self', $links['self']);
 
             unset($links['self']);
         }

tests/Unit/RelationshipLinkTest.php

@@ -311,12 +311,12 @@ public function testCreateWithoutSelfAndRelatedPropertiesThrowsException()
      *
      * @param mixed $input
      */
-    public function testSelfMustBeAString($input)
+    public function testSelfMustBeAStringOrObject($input)
     {
         $link = new RelationshipLink($this->manager, $this->relationship);
 
         // Input must be a string
-        if (gettype($input) === 'string') {
+        if (gettype($input) === 'string' or gettype($input) === 'object') {
             $this->assertInstanceOf('Art4\JsonApiClient\RelationshipLink', $link);
 
             return;
@@ -327,7 +327,7 @@ public function testSelfMustBeAString($input)
 
         $this->setExpectedException(
             'Art4\JsonApiClient\Exception\ValidationException',
-            'property "self" has to be a string, "' . gettype($input) . '" given.'
+            'property "self" has to be a string or object, "' . gettype($input) . '" given.'
         );
 
         $link->parse($object);

tests/Unit/V1/RelationshipLinkTest.php

@@ -264,20 +264,20 @@ public function testCreateWithoutSelfAndRelatedPropertiesThrowsException()
     }
 
     /**
-     * @dataProvider jsonValuesProviderWithoutString
+     * @dataProvider jsonValuesProviderWithoutObjectAndString
      *
      * self: a link for the relationship itself (a "relationship link").
      *
      * @param mixed $input
      */
-    public function testSelfMustBeAString($input)
+    public function testSelfMustBeAStringOrObject($input)
     {
         $object = new \stdClass();
         $object->self = $input;
 
         $this->expectException(ValidationException::class);
         $this->expectExceptionMessage(
-            'property "self" has to be a string, "' . gettype($input) . '" given.'
+            'property "self" has to be a string or object, "' . gettype($input) . '" given.'
         );
 
         $link = new RelationshipLink($object, $this->manager, $this->relationship);