Merge pull request pytest-dev#7 from werehuman/profiling-long-file-names

fix: avoid errors when filename is too long

pytest-profiling/README.md

@@ -89,6 +89,15 @@ pstats files (one per test item) are retained for later analysis in `prof` direc
     test_import.prof
 ```
 
+Profiling plugin by default names pstats filename as corresponding test name. If full path is longer that operation system allows then plugin renames it to first 4 bytes of md5 hash of test name:
+
+```bash
+    $ ls -1 prof/
+    combined.prof
+    test_not_longer_than_max_allowed.prof
+    68b329da.prof
+```
+
 If the ``--profile-svg`` option is given, along with the prof files and tabular output a svg file will be generated:
 
 ```bash

pytest-profiling/pytest_profiling.py

@@ -5,6 +5,11 @@
 import cProfile
 import pstats
 import pipes
+import errno
+from hashlib import md5
+
+
+LARGE_FILENAME_HASH_LEN = 8
 
 
 class Profiling(object):
@@ -50,9 +55,22 @@ def pytest_pyfunc_call(self, __multicall__, pyfuncitem):
         """Hook into pytest_pyfunc_call; marked as a tryfirst hook so that we
         can call everyone else inside `cProfile.runctx`.
         """
-        prof = os.path.join("prof", pyfuncitem.name + ".prof")
-        cProfile.runctx("fn()", globals(), dict(fn=__multicall__.execute), filename=prof)
-        self.profs.append(prof)
+        prof = cProfile.Profile()
+        prof.runctx("fn()", globals(), dict(fn=__multicall__.execute))
+        prof_filename = os.path.join("prof", pyfuncitem.name + ".prof")
+        try:
+            prof.dump_stats(prof_filename)
+        except EnvironmentError as err:
+            if err.errno != errno.ENAMETOOLONG:
+                raise
+
+            if len(pyfuncitem.name) < LARGE_FILENAME_HASH_LEN:
+                raise
+
+            hash_str = md5(pyfuncitem.name).hexdigest()[:LARGE_FILENAME_HASH_LEN]
+            prof_filename = os.path.join("prof", hash_str + ".prof")
+            prof.dump_stats(prof_filename)
+        self.profs.append(prof_filename)
 
 
 def pytest_addoption(parser):

pytest-profiling/tests/unit/test_profile.py

@@ -22,13 +22,16 @@ def test_hooks_pyfunc_call():
     multicall, pyfuncitem, plugin = Mock(), Mock(), Profiling(False)
     pyfuncitem.name.__add__ = Mock()
     with patch('os.path.join', return_value=sentinel.join):
-        with patch('pytest_profiling.cProfile') as cProfile:
+        with patch('pytest_profiling.cProfile.Profile') as Profile:
             plugin.pytest_pyfunc_call(multicall, pyfuncitem)
-    assert cProfile.runctx.called
-    args, kwargs = cProfile.runctx.call_args
-    assert kwargs['filename'] == sentinel.join
+    prof = Profile()  # mock instances are singletons
+    assert prof.runctx.called
+    assert prof.dump_stats.called
+    runctx_args, _ = prof.runctx.call_args
+    (dump_stats_filename, ), _ = prof.dump_stats.call_args
+    assert dump_stats_filename == sentinel.join
     assert not multicall.execute.called
-    eval(*args)
+    eval(*runctx_args)
     assert multicall.execute.called
     assert plugin.profs == [sentinel.join]