Changed behavior if --lf and --ff are both used.

AUTHORS

@@ -78,6 +78,7 @@ Javier Romero
 Jeff Widman
 John Towler
 Jon Sonesen
+Jonas Obrist
 Jordan Guymon
 Joshua Bronson
 Jurko Gospodnetić

CHANGELOG.rst

@@ -69,6 +69,9 @@ Changes
 * ``PluginManager.import_plugin`` now accepts unicode plugin names in Python 2.
   Thanks `@reutsharabani`_ for the PR.
 
+* fix `#2308`_: When using both ``--lf`` and ``--ff``, only the last failed tests are run.
+  Thanks `@ojii`_ for the PR.
+
 
 Bug Fixes
 ---------
@@ -88,6 +91,7 @@ Bug Fixes
 .. _@reutsharabani: https://github.com/reutsharabani
 .. _@unsignedint: https://github.com/unsignedint
 .. _@Kriechi: https://github.com/Kriechi
+.. _@ojii: https://github.com/ojii
 
 
 .. _#1407: https://github.com/pytest-dev/pytest/issues/1407
@@ -101,6 +105,7 @@ Bug Fixes
 .. _#2147: https://github.com/pytest-dev/pytest/issues/2147
 .. _#2208: https://github.com/pytest-dev/pytest/issues/2208
 .. _#2228:  https://github.com/pytest-dev/pytest/issues/2228
+.. _#2308: https://github.com/pytest-dev/pytest/issues/2308
 
 
 3.0.8 (unreleased)

_pytest/cacheprovider.py

@@ -139,11 +139,11 @@ def pytest_collection_modifyitems(self, session, config, items):
                 # running a subset of all tests with recorded failures outside
                 # of the set of tests currently executing
                 pass
-            elif self.config.getvalue("failedfirst"):
-                items[:] = previously_failed + previously_passed
-            else:
+            elif self.config.getvalue("lf"):
                 items[:] = previously_failed
                 config.hook.pytest_deselected(items=previously_passed)
+            else:
+                items[:] = previously_failed + previously_passed
 
     def pytest_sessionfinish(self, session):
         config = self.config

testing/test_cache.py

@@ -192,13 +192,37 @@ def test_always_fails():
             "test_a.py*",
             "test_b.py*",
         ])
-        result = testdir.runpytest("--lf", "--ff")
+        result = testdir.runpytest("--ff")
         # Test order will be failing tests firs
         result.stdout.fnmatch_lines([
             "test_b.py*",
             "test_a.py*",
         ])
 
+    def test_lastfailed_failedfirst_order(self, testdir):
+        testdir.makepyfile(**{
+            'test_a.py': """
+                def test_always_passes():
+                    assert 1
+            """,
+            'test_b.py': """
+                def test_always_fails():
+                    assert 0
+            """,
+        })
+        result = testdir.runpytest()
+        # Test order will be collection order; alphabetical
+        result.stdout.fnmatch_lines([
+            "test_a.py*",
+            "test_b.py*",
+        ])
+        result = testdir.runpytest("--lf", "--ff")
+        # Test order will be failing tests firs
+        result.stdout.fnmatch_lines([
+            "test_b.py*",
+        ])
+        assert 'test_a.py' not in result.stdout.str()
+
     def test_lastfailed_difference_invocations(self, testdir, monkeypatch):
         monkeypatch.setenv("PYTHONDONTWRITEBYTECODE", 1)
         testdir.makepyfile(test_a="""