Unit Tests not discovered in Visual Studio 2017

With Python 2.7 and higher you don't have to write new code or use third-party tools to do this; recursive test execution via the command line is built-in. Put an __init__.py in your test directory and:

python -m unittest discover <test_directory>
# or
python -m unittest discover -s <directory> -p '*_test.py'

You can read more in the python 2.7 or python 3.x unittest documentation.

Update for 2021:

Lots of modern python projects use more advanced tools like pytest. For example, pull down matplotlib or scikit-learn and you will see they both use it.

It is important to know about these newer tools because when you have more than 7000 tests you need:

• more advanced ways to summarize what passes, skipped, warnings, errors
• easy ways to see how they failed
• percent complete as it is running
• total run time
• ways to generate a test report
• etc etc

The best solution in my opinion is to use the unittest command line interface which will add the directory to the sys.path so you don't have to (done in the TestLoader class).

For example for a directory structure like this:

new_project
├── antigravity.py
└── test_antigravity.py

You can just run:

$ cd new_project
$ python -m unittest test_antigravity

For a directory structure like yours:

new_project
├── antigravity
│   ├── __init__.py         # make it a package
│   └── antigravity.py
└── test
    ├── __init__.py         # also make test a package
    └── test_antigravity.py

And in the test modules inside the test package, you can import the antigravity package and its modules as usual:

# import the package
import antigravity

# import the antigravity module
from antigravity import antigravity

# or an object inside the antigravity module
from antigravity.antigravity import my_object

Running a single test module:

To run a single test module, in this case test_antigravity.py:

$ cd new_project
$ python -m unittest test.test_antigravity

Just reference the test module the same way you import it.

Running a single test case or test method:

Also you can run a single TestCase or a single test method:

$ python -m unittest test.test_antigravity.GravityTestCase
$ python -m unittest test.test_antigravity.GravityTestCase.test_method

Running all tests:

You can also use test discovery which will discover and run all the tests for you, they must be modules or packages named test*.py (can be changed with the -p, --pattern flag):

$ cd new_project
$ python -m unittest discover
$ # Also works without discover for Python 3
$ # as suggested by @Burrito in the comments
$ python -m unittest

This will run all the test*.py modules inside the test package.