missing_diff_lines

Run missing_diff_lines() after you ran coverage.py in a git-repo, e.g. with coverage run -m unittest discover. It will output a set with tuples in the form (filename, line-number) for every line in the current diff, that has no test that covers it.

Example

Say you have this code in calc.py and no tests yet:

def mul(a, b):
    return a * b

You add some more cod:

def mul(a, b):
    return a * b

def div(a, b):
    if b == 0:
        return 0
    return a / b

As well as a test-suite:

class TestDiv(TestCase):

    def test_simple_div(self):
        self.assertEqual(3, div(9, 3))

Note, that the branch b == 0 is not covered. And indeed. if you run:

$ coverage run -m unittest discover && python3 report.py

Where this is the content of report.py:

from missing_diff_lines import missing_diff_lines
from pprint import pprint

print(missing_diff_lines())

You get

{('calc.py', 6)}

Which is correct, as this line is not covered. But note, that the not covered line 2 is not in the current diff and thus is not reported. This is the very purpose of this package.