单元测试：使用 init 方法模拟 python class

Question

I am trying to test a run method in my class which has init method and takes object as parameter from another class:

class ServePlate(FreeSurferStep):
    process_name = "FreeSurfer"
    step_name = "ServePlate"
    step_cli = "serve"
    cpu = 1
    mem = 1024

    def __init__(self, project, code, args):
        super(Stage, self).__init__(project, code, args)
        self.next_step = Autorecon1

    @classmethod
    def get_queue(cls, project_name):
        plog = ProcessingLog()
        available = plog.get_project_images(project_name, "T1")
        attempted = plog.get_step_attempted(project_name, cls.process_name, cls.step_name)
        attempted_codes = [row.Code for row in attempted]
        todo = [{'ProjectName': project_name, 'Code': row.Code} for row in available if row.Code not in attempted_codes]
        return todo

    def run(self):                        #<<<<-- This method is to be tested

        source = None
        image = ProcessingLog().get_project_image(self.project, self.code)
        if image.ImageStore == "Dicom":
            dcmtmp = tempfile.mkdtemp()
            DicomRepository().fetch_dicoms(self.code, dcmtmp)

            first_t1 = os.path.join(dcmtmp, os.listdir(dcmtmp)[0])
            niitmp = os.path.join(tempfile.mkdtemp(), 'raw.nii')
            cmd = 'dcm2niix -b n -z n -g i -o {} -f raw {}'.format(os.path.dirname(niitmp), first_t1)
            self._run_fs_cmd(cmd)

            source = niitmp
        elif image.ImageStore == "Pre-Processed":
            source = [PreProcessedImageRepository().get_image(self.code), ]

        if source is None:
            raise ProcessingError("Could not find staging data.")

        first_t1 = self._copy_files(source)

        cmd = 'recon-all -s %(code)s -i %(image)s' % {
            "code": self.code,
            "image": first_t1
        }
        self._run_fs_cmd(cmd).                  #<<<-- I am trying to check value of cmd variable

Here is my test, i am patching first the init method and second _run_fs_cmd frm another class.

class Testfs(unittest.TestCase):

    @patch.object(fs.FreeSurferStep, '_run_fs_cmd', spec=True)
    # @patch.object(fs.FreeSurferStep, '__init__')
    def test_serve(mock_serve):
        """
        Serve step test
        """
        mock_serve.project = 'TEST_FS'
        mock_serve.code = 'Test9001-1a5'
        mock_serve.args = ''
        mock_stage.return_value = None
        FsObj = FreeSurferStep('serve')
        stage_obj = Stage(FsObj)
        FsObj.run()
        #
        # stage_obj.run(self)
        #
        # self.assertEqual(self.cmd, '')
        # fs.FreeSurferStep._run_fs_cmd = Mock()

this gives me error. Here even though i am passing no arguments to the run method, it keeps on complaining about more argument being passed. Also patching a class object to be passed to ServePlate method and patching run_fsmethod where the cmd is passed to doesn't seem to work. Do i need to compulsorily mock all other methods being called?
TypeError: test_serve() takes 1 positional argument but 2 were given TypeError: run() takes 1 positional argument but 3 were given

Answer 1

i got the test working with initializing correctly:

class Testfs(unittest.TestCase):
    project = 'TEST'
    code = '9001-1a5'
    args = 'nogrid'

    @patch.object(fs.FreeSurferStep, '_run_fs_cmd', 'put_object', spec=True)
    @patch.object(fs.FreeSurferStep, '__init__')
    def test_serve(self, mock_test_serve):
        """
        Stage step test
        """
        mock_test_stage.return_value = None
        project = 'TEST'
        code = '9001-1a5'
        args = 'nogrid'

        self.logger = logging.getLogger(__name__)
        FsObj = fs.FreeSurferStep('Stage')

        stage_obj = fs.Stage(FsObj, code, args)
        stage_obj.project = 'Test'
        stage_obj.code = '9001-1a5'
        stage_obj.run()

however havent got a way to check value passed to `_run_fs_cmd` method