5. Pytest

Pytest is a utility to unit test python code.

We use nosetests and not __main__ to test all functionality so they can me automatically run and reports can be generated. A project that does not have a sufficient number of tests to make sure the module works can not be accepted.

5.1. Installation

The nose module can be installed with the help of pip utility

$ pip install pytest

This will install the pytest module in the current Python distribution, which means the test can be run using this utility as well as using –m switch. All tests are included in the folder tests.

For example for the cloudmesh-cloud module they are in

• https://github.com/cloudmesh/cloudmesh-cloud/tree/master/tests

Best is to add a numbe rto identify in which order they are run

+cm
  + cloudmesh
  + tests
    - test_01_topic1.py
    - test_02_topic2.py
    - test_03_topic2.py

5.2. Test Specification and Execution

A simple example for a test is

• https://github.com/cloudmesh/cloudmesh-cloud/blob/master/tests/test_key.py

Note that all test python programs have specific function names of the form

def test_number_topic (self)

The number is defined to order them and is typically something like 001, note the leading spaces. The topic is a descriptive term on what we test.

Each test starts with a setup function def setup(self) we declare a setup that is run prior to each test being executed. Other functions will use the setup prior to execution.

A function includes one or multiple asserts that check if a particular test succeeds and reports this to nose to expose the information if a tess succeds or fails, when running it

Note that all nosetest functions start with a HEADING() in the body which conveniently prints a banner with the function name and thus helps in debugging in case of errors.

Invocation is simply done with the comment lines you see on top that you will include.

in our case the test is called test_key.py so we include on the top

###############################################################
# pytest -v --capture=no tests/test_key.py
# pytest -v  tests/test_key.py
# pytest -v --capture=no -v --nocapture tests/test_key.py:Test_key.<METHIDNAME>
###############################################################

You can than execute the test with either command. More information is printed with the command

Make sure that you place this comment in your tests.

The following is our simple nosetests for key. THe file is stored at tests/test_key.py

First, we import the needed classes and methods we like to test. We define a class, and than we define the methods. such as the setup and the actual tests.

your run it with

$ pytest -v --capture=no tests/test_key.py

###############################################################
# pytest -v --capture=no tests/test_key.py
# pytest -v  tests/test_key.py
# pytest -v --capture=no -v --nocapture tests/test_key.py:Test_key.<METHIDNAME>
###############################################################
from pprint import pprint
from cloudmesh.common.Printer import Printer
from cloudmesh.common.util import HEADING
from cloudmesh.management.configuration.SSHkey import SSHkey
from cloudmesh.management.configuration.config import Config

@pytest.mark.incremental
class TestKey:

    def setup(self):
        self.sshkey = SSHkey()


    def test_01_key(self):
        HEADING()
        pprint(self.sshkey)
        print(self.sshkey)
        print(type(self.sshkey))
        pprint(self.sshkey.__dict__)

        assert self.sshkey.__dict__  is not None


    def test_02_git(self):
        HEADING()
        config = Config()
        username = config["cloudmesh.profile.github"]
        print ("Username:", username)
        keys = self.sshkey.get_from_git(username)
        pprint (keys)
        print(Printer.flatwrite(keys,
                            sort_keys=("name"),
                            order=["name", "fingerprint"],
                            header=["Name", "Fingerprint"])
              )

        assert len(keys) > 0

The output with pytest tests/test_key.py does not provide any detail, but just reports if tests fail or succeed.

----------------------------------------------------------------------
Ran 2 tests in 0.457s

OK

The output with nosetests -v tests/test_key.py

results in

tests.test_key.TestName.test_01_key ... ok
tests.test_key.TestName.test_02_git ... ok

----------------------------------------------------------------------
Ran 2 tests in 1.072s

OK

During development phase you want to use nosetests -v --nocapture tests/test_key.py

WHich prints all print statements also