/**
  * Test if both source and target join fields can be specified.
  */
 public function testSourceAndTargetJoinFieldsSpecified()
 {
     $collection = new WritersCollection($this->connection, $this->pool);
     $collection->setJoinTable('writes_books', ['source_id', 'target_id']);
     $this->assertEquals('writes_books', $collection->getJoinTable());
     $this->assertEquals('source_id', $collection->getSourceJoinField());
     $this->assertEquals('target_id', $collection->getTargetJoinField());
 }