When directories are provided to combine data files, fail if one doesn't exist.

1 files changed, 13 insertions, 1 deletions

diff --git a/tests/test_data.py b/tests/test_data.py
index c2bb9a0f..ce49bcbf 100644
--- a/tests/test_data.py
+++ b/tests/test_data.py
@@ -670,10 +670,22 @@ class CoverageDataFilesTest(DataTestHelpers, CoverageTest):
         os.makedirs('cov2')
         covdata2.write_file('cov2/.coverage.2')
 
+        # This data won't be included.
+        covdata_xxx = CoverageData()
+        covdata_xxx.set_arcs(ARCS_3)
+        covdata_xxx.write_file('.coverage.xxx')
+
         covdata3 = CoverageData()
-        self.data_files.combine_parallel_data(covdata3, data_dirs=['cov1/', 'cov2/'])
+        self.data_files.combine_parallel_data(covdata3, data_dirs=['cov1', 'cov2'])
 
         self.assert_line_counts(covdata3, SUMMARY_1_2)
         self.assert_measured_files(covdata3, MEASURED_FILES_1_2)
         self.assert_doesnt_exist("cov1/.coverage.1")
         self.assert_doesnt_exist("cov2/.coverage.2")
+        self.assert_exists(".coverage.xxx")
+
+    def test_combining_from_nonexistent_directories(self):
+        covdata = CoverageData()
+        msg = "Couldn't combine from non-existent directory 'xyzzy'"
+        with self.assertRaisesRegex(CoverageException, msg):
+            self.data_files.combine_parallel_data(covdata, data_dirs=['xyzzy'])