Debugging Python Test Failures with pytest

An overview of the pytest flags that help with debugging. From Chapter 13, Debugging Test Failures, of Python Testing with pytest, 2nd edition (https://pythontest.com/pytest-book/). pytest includes quite a few command-line flags that are useful for debugging. We talk about thes flags in this episode. Flags for selecting which tests to run, in which order, and when to stop: * -lf / --last-failed: Runs just the tests that failed last. * -ff / --failed-failed: Runs all the tests, starting with the last failed. * -x / --exitfirst: Stops the tests session afterEd: after?Author: yep the first failure. * --maxfail=num: Stops the tests after num failures. * -nf / --new-first: Runs all the tests, ordered by file modification time. * --sw / --stepwise: Stops the tests at the first failure. Starts the tests at the last failure next time. * --sw-skip / --stepwise-skip: Same as --sw, but skips the first failure. Flags to control pytest output: * -v / --verbose Displays all the test names, passing or failing. * --tb=[auto/long/short/line/native/no] Controls the traceback style. * -l / --showlocals Displays local variables alongside the stacktrace. Flags to start a command-line debugger: * --pdb Starts an interactive debugging session at the point of failure. * --trace Starts the pdb source-code debugger immediately when running each test. * --pdbcls Uses alternatives to pdb, such as IPython’s debugger with –-pdbcls=IPython.terminal.debugger:TerminalPdb. This list is also found in Chapter 13 of Python Testing with pytest, 2nd edition (https://pythontest.com/pytest-book/). The chapter is "Debugging Test Failures" and covers way more than just debug flags, while walking through debugging 2 test failures.