getMockBuilder(\Magento\Framework\ObjectManagerInterface::class) ->disableOriginalConstructor() ->getMock(); $selectRender = $this->getMockBuilder(\Magento\Framework\DB\Select\SelectRenderer::class) ->disableOriginalConstructor() ->getMock(); $objectManager->expects($this->once()) ->method('get') ->with(\Magento\Framework\DB\Select\SelectRenderer::class) ->willReturn($selectRender); $selectMock = $this->getMockBuilder(\Magento\Framework\DB\Select::class) ->disableOriginalConstructor() ->getMock(); $selectRender->expects($this->once()) ->method('render') ->with($selectMock, '') ->willReturn('sql'); $model = new \Magento\Framework\DB\Select\RendererProxy($objectManager); $this->assertEquals('sql', $model->render($selectMock, '')); } }