The runner printed a wall of text and I scrolled past it. The summary line is the answer, and the failure block under it is the reason. Learn to read those two and the rest is noise.
About 1 min of reading
Before this new lesson, one small question about the lesson you just finished. Recall it, do not look it up.
Run a file with a deliberate failure and read only the verdict and the failure block.
Run the file. The verdict line tells you one claim failed.
Before you run it, say out loud what it will print. Then open the answer.
Open the failure block. It names the function and the assert line that did not hold.
Before you run it, say out loud what it will print. Then open the answer.
Every runner output has a verdict line (counts) and, when something failed, a block per failure (which function, which line). Everything else is decoration. Train your eye to jump to the counts, then to the first FAILED block.
A passing run means the claims you wrote held. It does not mean the program is right, it means it is right where you tested. The empty space between your claims is untested. That gap is the honest meaning of green.
3 passed, 1 failedThis is the whole result in one line. If you read nothing else, read this. It counts the claims and how many broke.
FAILED test_add.py::test_add_negative
assert add(-1, -1) == 0Under the summary, each failure names its function and shows the line that did not hold. This is the reason, not a stack of your program.
pytest -q test_add.py-q trims the run to the summary and failures. Useful when the full output is too long and you only want the verdict.
Each one is defined here on this site. Open the entry for the full definition and the other words it points at.