Run setUp only once for a set of automated tests

Question

My Python version is 2.6.

I would like to execute the test setUp method only once since I do things there which are needed for all tests.

My idea was to crea

Answer 1

for python >3 you can do it by defining startTestRun,stopTestRun of unittest.TestResult class. answer https://stackoverflow.com/a/64892396/2679740

Answer 2

I'm using Python 3 and found that the cls reference is also available in the setup method and so the following works:

class TestThing(unittest.TestCase):

  @classmethod
  def setUpClass(cls):
    cls.thing = Thing() # the `thing` is only instantiated once

  def setup(self):
    self.thing = cls.thing # ...but set on each test case instance

  def test_the_thing(self):
    self.assertTrue(self.thing is not None)

Answer 3

Don't try to dedupe the calls to setUp, just call it once.

For example:

class MyClass(object):
    ...

def _set_up():
    code to do one-time setup

_set_up()

This will call _set_up() when the module's first loaded. I've defined it to be a module-level function, but you could equally make it a class method of MyClass.

Answer 4

Place all code you want set up once outside the mySelTest.

setup_done = False

class mySelTest(unittest.TestCase):

    def setUp(self):
        print str(setup_done)

        if setup_done:
            return

        setup_done = True
        print str(setup_done)

Another possibility is having a Singleton class that you instantiate in setUp(), which will only run the __new__ code once and return the object instance for the rest of the calls. See: Is there a simple, elegant way to define singletons?

class Singleton(object):
    _instance = None
    def __new__(cls, *args, **kwargs):
        if not cls._instance:
            cls._instance = super(Singleton, cls).__new__(
                            cls, *args, **kwargs)
            # PUT YOUR SETUP ONCE CODE HERE!
            cls.setUpBool = True

        return cls._instance

class mySelTest(unittest.TestCase):

    def setUp(self):
        # The first call initializes singleton, ever additional call returns the instantiated reference.
        print(Singleton().setUpBool)

Your way works too though.

Answer 5

You can use setUpClass to define methods that only run once per testsuite.

Answer 6

setup_done is a class variable, not an instance variable.

You are referencing it as an instance variable:

self.setup_done

But you need to reference it as a class variable:

mySelTest.setup_done

Here's the corrected code:

class mySelTest(unittest.TestCase):
    setup_done = False

    def setUp(self):
        print str(mySelTest.setup_done)

        if mySelTest.setup_done:
            return
        mySelTest.setup_done = True
        print str(mySelTest.setup_done)