Reland of expect_tests > coverage: no data, no fail (patchset #1 id:1 of https://codereview.chromium

expect_tests/cover.py

Index: expect_tests/cover.py
diff --git a/expect_tests/cover.py b/expect_tests/cover.py
index dee4f16a05cc3991720c38573f112a368a33d670..44d4a35631822b151185171f8c9c4aa59bffc933 100644
--- a/expect_tests/cover.py
+++ b/expect_tests/cover.py
@@ -110,7 +110,19 @@ class CoverageContext(object):
         self.cov.html_report(directory=self.html_report)
 
       outf = StringIO()
-      coverage_percent = self.cov.report(file=outf, show_missing=True)
+
+      try:
+        coverage_percent = self.cov.report(file=outf, show_missing=True)
+      except coverage.CoverageException as ce:
+        if ce.message != 'No data to report.':
+          raise
+        # If we have no data to report, this means that coverage has found no
+        # tests in the module. Earlier version of coverage used to return 100 in
+        # this case, so we simulate it to keep backward compatibility.
+        coverage_percent = 100.0
+        if verbose:
+          print 'No data to report, setting coverage to 100%'
+
       fail = coverage_percent < self.expected_coverage_min
       summary = outf.getvalue().replace('%- 15s' % 'Name', 'Coverage Report', 1)
       if verbose: