fix: an empty file shouldn't fail with --fail-under=99. #1470

CHANGES.rst

@@ -25,12 +25,16 @@ Unreleased
   use ``--format=markdown`` to get the table in Markdown format, thanks to
   Steve Oswald in `pull 1479`_, closing `issue 1418`_.
 
+- An empty file has a coverage total of 100%, but used to fail with
+  ``--fail-under``.  This has been fixed, closing `issue 1470`_.
+
 - Fixed a mis-measurement of a strange use of wildcard alternatives in
   match/case statements, closing `issue 1421`_.
 
 .. _pull 1479: https://github.com/nedbat/coveragepy/pull/1479
 .. _issue 1418: https://github.com/nedbat/coveragepy/issues/1418
 .. _issue 1421: https://github.com/nedbat/coveragepy/issues/1421
+.. _issue 1470: https://github.com/nedbat/coveragepy/issues/1470
 
 
 .. _changes_6-6-0b1:

coverage/summary.py

@@ -165,7 +165,7 @@ def report(self, morfs, outfile=None):
         else:
             self.tabular_report()
 
-        return self.total.n_statements and self.total.pc_covered
+        return self.total.pc_covered
 
     def tabular_report(self):
         """Writes tabular report formats."""

tests/test_process.py

@@ -1093,7 +1093,8 @@ def test_report(self):
         st, _ = self.run_command_status("coverage run empty.py")
         assert st == 0
         st, _ = self.run_command_status("coverage report")
-        assert st == 2
+        # An empty file is marked as 100% covered, so this is ok.
+        assert st == 0
 
 
 @pytest.mark.skipif(env.WINDOWS, reason="Windows can't delete the directory in use.")