Documenting function and addng another test case

Cake/ORM/Entity.php

@@ -443,7 +443,22 @@ public function isNew($new = null) {
 		return $this->_persisted = (bool)$new;
 	}
 
-	public function validate(Validator $validator, array $fieldList) {
+/**
+ * Validates the internal properties using a validator object. The resulting
+ * errors will be copied inside this entity and can be retrieved using the
+ * `errors` method.
+ *
+ * The second argument can be used to restrict the fields that need to be passed
+ * to the validator object.
+ *
+ * This function returns true if there were no validation errors or false
+ * otherwise.
+ *
+ * @param \Cake\Validation\Validator $validator
+ * @param array $fieldList The fields to be passed to the validator
+ * @return boolean
+ */
+	public function validate(Validator $validator, array $fieldList = []) {
 		if (empty($fieldList)) {
 			$fieldList = array_keys($this->_properties);
 		}
@@ -460,7 +475,7 @@ public function validate(Validator $validator, array $fieldList) {
 		}
 
 		$new = $this->isNew();
-		$this->errors($validator->errors($data, $new === null ? true : false));
+		$this->errors($validator->errors($data, $new === null ? true : $new));
 		return empty($this->_errors);
 	}
 

Cake/Test/TestCase/ORM/EntityTest.php

@@ -690,4 +690,26 @@ public function testValidateOnlyFieldsInList() {
 		$this->assertEquals(['something' => ['not valid']], $entity->errors());
 	}
 
+/**
+ * Tests validate when called with no fieldList, it also tests the case when
+ * the validator returns no errors
+ *
+ * @return void
+ */
+	public function testValidateNoFieldList() {
+		$validator = $this->getMock('\Cake\Validation\Validator');
+		$data = [
+			'a' => 'b',
+			'cool' => false,
+			'something' => true
+		];
+		$entity = new Entity($data);
+		$entity->isNew(true);
+
+		$validator->expects($this->once())->method('errors')
+			->with($data, true)
+			->will($this->returnValue([]));
+		$this->assertTrue($entity->validate($validator));
+		$this->assertEquals([], $entity->errors());
+	}
 }