bpo-4080: unittest durations (#12271)

4 files changed, 67 insertions, 6 deletions

diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
index 5167c5f..018f22e 100644
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -9,6 +9,7 @@ import warnings
 import collections
 import contextlib
 import traceback
+import time
 import types
 
 from . import result
@@ -572,6 +573,15 @@ class TestCase(object):
         else:
             addUnexpectedSuccess(self)
 
+    def _addDuration(self, result, elapsed):
+        try:
+            addDuration = result.addDuration
+        except AttributeError:
+            warnings.warn("TestResult has no addDuration method",
+                          RuntimeWarning)
+        else:
+            addDuration(self, elapsed)
+
     def _callSetUp(self):
         self.setUp()
 
@@ -612,6 +622,7 @@ class TestCase(object):
                 getattr(testMethod, "__unittest_expecting_failure__", False)
             )
             outcome = _Outcome(result)
+            start_time = time.perf_counter()
             try:
                 self._outcome = outcome
 
@@ -625,6 +636,7 @@ class TestCase(object):
                     with outcome.testPartExecutor(self):
                         self._callTearDown()
                 self.doCleanups()
+                self._addDuration(result, (time.perf_counter() - start_time))
 
                 if outcome.success:
                     if expecting_failure:
diff --git a/Lib/unittest/main.py b/Lib/unittest/main.py
index 046fbd3..0792750 100644
--- a/Lib/unittest/main.py
+++ b/Lib/unittest/main.py
@@ -66,7 +66,8 @@ class TestProgram(object):
     def __init__(self, module='__main__', defaultTest=None, argv=None,
                     testRunner=None, testLoader=loader.defaultTestLoader,
                     exit=True, verbosity=1, failfast=None, catchbreak=None,
-                    buffer=None, warnings=None, *, tb_locals=False):
+                    buffer=None, warnings=None, *, tb_locals=False,
+                    durations=None):
         if isinstance(module, str):
             self.module = __import__(module)
             for part in module.split('.')[1:]:
@@ -82,6 +83,7 @@ class TestProgram(object):
         self.verbosity = verbosity
         self.buffer = buffer
         self.tb_locals = tb_locals
+        self.durations = durations
         if warnings is None and not sys.warnoptions:
             # even if DeprecationWarnings are ignored by default
             # print them anyway unless other warnings settings are
@@ -178,6 +180,9 @@ class TestProgram(object):
         parser.add_argument('--locals', dest='tb_locals',
                             action='store_true',
                             help='Show local variables in tracebacks')
+        parser.add_argument('--durations', dest='durations', type=int,
+                            default=None, metavar="N",
+                            help='Show the N slowest test cases (N=0 for all)')
         if self.failfast is None:
             parser.add_argument('-f', '--failfast', dest='failfast',
                                 action='store_true',
@@ -258,9 +263,10 @@ class TestProgram(object):
                                                  failfast=self.failfast,
                                                  buffer=self.buffer,
                                                  warnings=self.warnings,
-                                                 tb_locals=self.tb_locals)
+                                                 tb_locals=self.tb_locals,
+                                                 durations=self.durations)
                 except TypeError:
-                    # didn't accept the tb_locals argument
+                    # didn't accept the tb_locals or durations argument
                     testRunner = self.testRunner(verbosity=self.verbosity,
                                                  failfast=self.failfast,
                                                  buffer=self.buffer,
diff --git a/Lib/unittest/result.py b/Lib/unittest/result.py
index 5ca4c23..fa9bea4 100644
--- a/Lib/unittest/result.py
+++ b/Lib/unittest/result.py
@@ -43,6 +43,7 @@ class TestResult(object):
         self.skipped = []
         self.expectedFailures = []
         self.unexpectedSuccesses = []
+        self.collectedDurations = []
         self.shouldStop = False
         self.buffer = False
         self.tb_locals = False
@@ -157,6 +158,12 @@ class TestResult(object):
         """Called when a test was expected to fail, but succeed."""
         self.unexpectedSuccesses.append(test)
 
+    def addDuration(self, test, elapsed):
+        """Called when a test finished to run, regardless of its outcome."""
+        # support for a TextTestRunner using an old TestResult class
+        if hasattr(self, "collectedDurations"):
+            self.collectedDurations.append((test, elapsed))
+
     def wasSuccessful(self):
         """Tells whether or not this result was a success."""
         # The hasattr check is for test_result's OldResult test.  That
diff --git a/Lib/unittest/runner.py b/Lib/unittest/runner.py
index 6678adb..a51c5c5 100644
--- a/Lib/unittest/runner.py
+++ b/Lib/unittest/runner.py
@@ -35,13 +35,16 @@ class TextTestResult(result.TestResult):
     separator1 = '=' * 70
     separator2 = '-' * 70
 
-    def __init__(self, stream, descriptions, verbosity):
+    def __init__(self, stream, descriptions, verbosity, *, durations=None):
+        """Construct a TextTestResult. Subclasses should accept **kwargs
+        to ensure compatibility as the interface changes."""
         super(TextTestResult, self).__init__(stream, descriptions, verbosity)
         self.stream = stream
         self.showAll = verbosity > 1
         self.dots = verbosity == 1
         self.descriptions = descriptions
         self._newline = True
+        self.durations = durations
 
     def getDescription(self, test):
         doc_first_line = test.shortDescription()
@@ -168,7 +171,7 @@ class TextTestRunner(object):
 
     def __init__(self, stream=None, descriptions=True, verbosity=1,
                  failfast=False, buffer=False, resultclass=None, warnings=None,
-                 *, tb_locals=False):
+                 *, tb_locals=False, durations=None):
         """Construct a TextTestRunner.
 
         Subclasses should accept **kwargs to ensure compatibility as the
@@ -182,12 +185,41 @@ class TextTestRunner(object):
         self.failfast = failfast
         self.buffer = buffer
         self.tb_locals = tb_locals
+        self.durations = durations
         self.warnings = warnings
         if resultclass is not None:
             self.resultclass = resultclass
 
     def _makeResult(self):
-        return self.resultclass(self.stream, self.descriptions, self.verbosity)
+        try:
+            return self.resultclass(self.stream, self.descriptions,
+                                    self.verbosity, durations=self.durations)
+        except TypeError:
+            # didn't accept the durations argument
+            return self.resultclass(self.stream, self.descriptions,
+                                    self.verbosity)
+
+    def _printDurations(self, result):
+        if not result.collectedDurations:
+            return
+        ls = sorted(result.collectedDurations, key=lambda x: x[1],
+                    reverse=True)
+        if self.durations > 0:
+            ls = ls[:self.durations]
+        self.stream.writeln("Slowest test durations")
+        if hasattr(result, 'separator2'):
+            self.stream.writeln(result.separator2)
+        hidden = False
+        for test, elapsed in ls:
+            if self.verbosity < 2 and elapsed < 0.001:
+                hidden = True
+                continue
+            self.stream.writeln("%-10s %s" % ("%.3fs" % elapsed, test))
+        if hidden:
+            self.stream.writeln("\n(durations < 0.001s were hidden; "
+                                "use -v to show these durations)")
+        else:
+            self.stream.writeln("")
 
     def run(self, test):
         "Run the given test case or test suite."
@@ -213,8 +245,12 @@ class TextTestRunner(object):
             stopTime = time.perf_counter()
         timeTaken = stopTime - startTime
         result.printErrors()
+        if self.durations is not None:
+            self._printDurations(result)
+
         if hasattr(result, 'separator2'):
             self.stream.writeln(result.separator2)
+
         run = result.testsRun
         self.stream.writeln("Ran %d test%s in %.3fs" %
                             (run, run != 1 and "s" or "", timeTaken))