[BUGFIX] Don't resolve a schema id against itself (#452)

* Don't resolve a schema id against itself

* Add test for double-resolve bugfix

Author: erayd

src/JsonSchema/SchemaStorage.php

@@ -92,7 +92,7 @@ private function expandRefs(&$schema, $base = null)
             return;
         }
 
-        if (property_exists($schema, 'id') && is_string($schema->id)) {
+        if (property_exists($schema, 'id') && is_string($schema->id) && $base != $schema->id) {
             $base = $this->uriResolver->resolve($schema->id, $base);
         }
 

tests/SchemaStorageTest.php

@@ -302,4 +302,25 @@ public function testMetaSchemaFixes()
         $this->assertEquals('uri-reference', $draft_03->properties->{'$ref'}->format);
         $this->assertEquals('uri-reference', $draft_04->properties->id->format);
     }
+
+    public function testNoDoubleResolve()
+    {
+        $schemaOne = json_decode('{"id": "test/schema", "$ref": "../test2/schema2"}');
+
+        $uriRetriever = $this->prophesize('JsonSchema\UriRetrieverInterface');
+        $uriRetriever->retrieve('test/schema')->willReturn($schemaOne)->shouldBeCalled();
+
+        $s = new SchemaStorage($uriRetriever->reveal());
+        $schema = $s->addSchema('test/schema');
+
+        $r = new \ReflectionObject($s);
+        $p = $r->getProperty('schemas');
+        $p->setAccessible(true);
+        $schemas = $p->getValue($s);
+
+        $this->assertEquals(
+            'file://' . getcwd() . '/test2/schema2#',
+            $schemas['test/schema']->{'$ref'}
+        );
+    }
 }