added tests for --cov-report=""

Author: wolph

cov-core/cov_core.py

@@ -78,11 +78,13 @@ def sep(stream, s, txt):
 
     def summary(self, stream):
         """Produce coverage reports."""
-        if self.cov_report == ['']:
-            return
-
         total = 0
 
+        if self.cov_report == ['']:
+            with open(os.devnull, 'w') as null:
+                total = self.cov.report(show_missing=True, ignore_errors=True, file=null)
+                return total
+
         # Output coverage section header.
         if len(self.node_descs) == 1:
             self.sep(stream, '-', 'coverage: %s' % ''.join(self.node_descs))

pytest-cov/pytest_cov.py

@@ -155,6 +155,7 @@ def pytest_terminal_summary(self, terminalreporter):
             return
         if not (self.failed and self.options.no_cov_on_fail):
             total = self.cov_controller.summary(terminalreporter.writer)
+            assert total is not None, 'Test coverage should never be `None`'
             cov_min = self.options.cov_min
             if cov_min is not None and total < cov_min:
                 raise CoverageError(('Required test coverage of %d%% not '

pytest-cov/test_pytest_cov.py

@@ -142,6 +142,7 @@ def test_cov_min_no_report(testdir):
 
     result = testdir.runpytest('-v',
                                '--cov', '--cov-source=%s' % script.dirpath(),
+                               '--cov-report=',
                                '--cov-min=50',
                                script)