Add a no_cover marker/fixture. Close #78.

Author: ionelmc

src/pytest_cov/engine.py

@@ -31,6 +31,14 @@ def __init__(self, cov_source, cov_report, cov_config, cov_append, cov_branch, c
         self.failed_slaves = []
         self.topdir = os.getcwd()
 
+    def pause(self):
+        self.cov.stop()
+        self.unset_env()
+
+    def resume(self):
+        self.cov.start()
+        self.set_env()
+
     def set_env(self):
         """Put info about coverage into the env so that subprocesses can activate coverage."""
         if self.cov_source is None:

src/pytest_cov/plugin.py

@@ -3,6 +3,8 @@
 
 import pytest
 import argparse
+
+import sys
 from coverage.misc import CoverageException
 
 from . import embed
@@ -283,6 +285,20 @@ def pytest_runtest_teardown(self, item):
             embed.cleanup(self.cov)
             self.cov = None
 
+    @compat.hookwrapper
+    def pytest_runtest_call(self, item):
+        if item.get_marker("no_cover") or "no_cover" in item.fixturenames:
+            self.cov_controller.pause()
+            yield
+            self.cov_controller.resume()
+        else:
+            yield
+
+
+@pytest.fixture
+def no_cover():
+    pass
+
 
 @pytest.fixture
 def cov(request):
@@ -294,3 +310,7 @@ def cov(request):
         if plugin.cov_controller:
             return plugin.cov_controller.cov
     return None
+
+
+def pytest_configure(config):
+    config.addinivalue_line("markers", "no_cover: disable coverage for this test.")

tests/test_pytest_cov.py

@@ -229,7 +229,7 @@ def test_annotate_output_dir(testdir):
     assert result.ret == 0
 
 
-def test_html_output_dir(testdir,prop):
+def test_html_output_dir(testdir, prop):
     script = testdir.makepyfile(SCRIPT)
 
     result = testdir.runpytest('-v',
@@ -1015,6 +1015,46 @@ def test_cover_conftest_dist(testdir):
     result.stdout.fnmatch_lines([CONF_RESULT])
 
 
+def test_no_cover_marker(testdir):
+    testdir.makepyfile(mod=MODULE)
+    script = testdir.makepyfile('''
+import pytest
+import mod
+import subprocess
+import sys
+
+@pytest.mark.no_cover
+def test_basic():
+    mod.func()
+    subprocess.check_call([sys.executable, '-c', 'from mod import func; func()'])    
+''')
+    result = testdir.runpytest('-v', '-ra', '--strict',
+                               '--cov=%s' % script.dirpath(),
+                               '--cov-report=term-missing',
+                               script)
+    assert result.ret == 0
+    result.stdout.fnmatch_lines(['mod* 2 * 1 * 50% * 2'])
+
+
+def test_no_cover_fixture(testdir):
+    testdir.makepyfile(mod=MODULE)
+    script = testdir.makepyfile('''
+import mod
+import subprocess
+import sys
+
+def test_basic(no_cover):
+    mod.func()
+    subprocess.check_call([sys.executable, '-c', 'from mod import func; func()'])    
+''')
+    result = testdir.runpytest('-v', '-ra', '--strict',
+                               '--cov=%s' % script.dirpath(),
+                               '--cov-report=term-missing',
+                               script)
+    assert result.ret == 0
+    result.stdout.fnmatch_lines(['mod* 2 * 1 * 50% * 2'])
+
+
 COVERAGERC = '''
 [report]
 # Regexes for lines to exclude from consideration