public function testGetMappingByClassNameReturnsNull()
 {
     $this->assertEquals(Mapping::null(), $this->transformer->getMappingByClassName(PHPUnit_Framework_TestCase::class));
 }
 /**
  * @param string $className
  *
  * @return Mapping
  */
 public function getMappingByClassName(string $className) : Mapping
 {
     $className = ltrim($className, '\\');
     return !empty($this->mappings[$className]) ? $this->mappings[$className] : Mapping::null();
 }
 public function testMappingCanBeNull()
 {
     $nullable = Mapping::null();
     $this->assertTrue($nullable->isNull());
 }