fix #1478: add make command to re-run tests failed on last run

HISTORY.rst

@@ -10,6 +10,7 @@
   the number of physical CPUs in case /proc/cpuinfo does not provide this info.
 - 1458_: provide coloured test output. Also show failures on KeyboardInterrupt.
 - 1464_: various docfixes (always point to python3 doc, fix links, etc.).
+- 1478_: add make command to re-run tests failed on last run.
 
 **Bug fixes**
 

Makefile

@@ -49,6 +49,7 @@ clean:  ## Remove all build files.
 		*.egg-info \
 		*\$testfn* \
 		.coverage \
+		.failed-tests.txt \
 		.tox \
 		build/ \
 		dist/ \
@@ -151,6 +152,10 @@ test-by-name:  ## e.g. make test-by-name ARGS=psutil.tests.test_system.TestSyste
 	${MAKE} install
 	@$(TEST_PREFIX) $(PYTHON) -m unittest -v $(ARGS)
 
+test-failed:  ## Re-run tests which failed on last run
+	${MAKE} install
+	$(TEST_PREFIX) $(PYTHON) -c "import psutil.tests.runner as r; r.run(last_failed=True)"
+
 test-coverage:  ## Run test coverage.
 	${MAKE} install
 	# Note: coverage options are controlled by .coveragerc file

psutil/tests/runner.py

@@ -24,11 +24,13 @@
 
 import psutil
 from psutil._common import memoize
+from psutil.tests import safe_rmpath
 from psutil.tests import TOX
 
 
 HERE = os.path.abspath(os.path.dirname(__file__))
 VERBOSITY = 1 if TOX else 2
+FAILED_TESTS_FNAME = '.failed-tests.txt'
 if os.name == 'posix':
     GREEN = 1
     RED = 2
@@ -157,15 +159,36 @@ def get_suite(name=None):
     return suite
 
 
-def run(name=None):
+def get_suite_from_failed():
+    # ...from previously failed test run
+    with open(FAILED_TESTS_FNAME, 'rt') as f:
+        names = f.read().split()
+    suite = unittest.TestSuite()
+    for n in names:
+        suite.addTest(unittest.defaultTestLoader.loadTestsFromName(n))
+    return suite
+
+
+def save_failed_tests(result):
+    if result.wasSuccessful():
+        return safe_rmpath(FAILED_TESTS_FNAME)
+    with open(FAILED_TESTS_FNAME, 'wt') as f:
+        for t in result.errors + result.failures:
+            tname = str(t[0])
+            f.write(tname + '\n')
+
+
+def run(name=None, last_failed=False):
     setup_tests()
     runner = ColouredRunner(verbosity=VERBOSITY)
+    suite = get_suite_from_failed() if last_failed else get_suite(name)
     try:
-        result = runner.run(get_suite(name))
+        result = runner.run(suite)
     except (KeyboardInterrupt, SystemExit) as err:
         print("received %s" % err.__class__.__name__, file=sys.stderr)
         runner.result.printErrors()
         sys.exit(1)
     else:
+        save_failed_tests(result)
         success = result.wasSuccessful()
         sys.exit(0 if success else 1)

scripts/internal/winmake.py

@@ -318,6 +318,7 @@ def clean():
         "*.~",
         "*__pycache__",
         ".coverage",
+        ".failed-tests.txt",
         ".tox",
     )
     safe_rmtree("build")
@@ -439,6 +440,15 @@ def test_by_name():
     sh("%s -m unittest -v %s" % (PYTHON, name))
 
 
+@cmd
+def test_failed():
+    """Re-run tests which failed on last run."""
+    install()
+    test_setup()
+    sh('%s -c "import psutil.tests.runner as r; r.run(last_failed=True)"' % (
+        PYTHON))
+
+
 @cmd
 def test_script():
     """Quick way to test a script"""