public function testFindEager()
 {
     parent::testFindEager();
     $products = Product::find()->with('supplier')->all();
     $this->assertEquals(3, count($products));
     $this->assertTrue($products[0]->isRelationPopulated('supplier'));
     $this->assertTrue($products[1]->isRelationPopulated('supplier'));
     $this->assertTrue($products[2]->isRelationPopulated('supplier'));
     $this->assertEquals(1, count($products[0]->supplier));
     $this->assertEquals(0, count($products[1]->supplier));
     $this->assertEquals(0, count($products[2]->supplier));
 }