You don't have to run your tests manually. Pytest finds and executes them automatically:

# tests/test_positive.pydef test_pos_1():    populate_page()    check_values()def test_pos_2():    process_entry()    validate_result()

and

# tests/test_negative.pydef test_neg_1():    populate_page()    validate_error()

If you then run

py.test

They should automatically be picked up.

You can then also select a single file

py.test -k tests/test_negative.py

or a single test

py.test -k test_neg_1

Start file names and tests with either test_ or end with _test.py. Classes should begin with Test

Directory example:
|-- files
|--|-- stuff_in stuff
|--|--|-- blah.py
|--|-- example.py
|
|-- tests
|--|-- stuff_in stuff
|--|--|-- test_blah.py
|--|-- test_example.py

In terminal: $ py.test --cov=files/ tests/ or just $ py.test tests/ if you don't need code coverage. The test directory file path must be in your current directory path. Or an exact file path ofcourse

With the above terminal command ($ py.test tests/), pytest will search the tests/ directory for all files beginning with test_. The same goes for the file.

test_example.py

# imports heredef test_try_this():       assert 1 == 1# orclass TestThis:    assert 1 == 0# or even:def what_test():    assert True

You need to change the class name

class Positive_tests: to--> class Test_Positive: 

The class name should also start with "Test" in order to be discovered by Pytest. If you don't want to use "Test" in front of your class name you can configure that too, official doc here