Cleaner tests of the file matchers

2 files changed, 38 insertions, 28 deletions

diff --git a/tests/coveragetest.py b/tests/coveragetest.py
index 0467d808..a309f17d 100644
--- a/tests/coveragetest.py
+++ b/tests/coveragetest.py
@@ -167,13 +167,15 @@ class CoverageTest(TestCase):
         return self.captured_stderr.getvalue()
 
     def make_file(self, filename, text="", newline=None):
-        """Create a temp file.
+        """Create a file for testing.
 
-        `filename` is the path to the file, including directories if desired,
-        and `text` is the content. If `newline` is provided, it is a string
-        that will be used as the line endings in the created file.
+        `filename` is the relative path to the file, including directories if
+        desired, which will be created if need be.  `text` is the content to
+        create in the file. If `newline` is provided, it is a string that will
+        be used as the line endings in the created file, otherwise the line
+        endings are as provided in `text`.
 
-        Returns the path to the file.
+        Returns `filename`.
 
         """
         # Tests that call `make_file` should be run in a temp environment.
diff --git a/tests/test_files.py b/tests/test_files.py
index 85c0ac7b..42457a5c 100644
--- a/tests/test_files.py
+++ b/tests/test_files.py
@@ -50,41 +50,49 @@ class FileLocatorTest(CoverageTest):
 class MatcherTest(CoverageTest):
     """Tests of file matchers."""
 
+    def setUp(self):
+        super(MatcherTest, self).setUp()
+        self.fl = FileLocator()
+
+    def assertMatches(self, matcher, filepath, matches):
+        """The `matcher` should agree with `matches` about `filepath`."""
+        canonical = self.fl.canonical_filename(filepath)
+        self.assertEqual(
+            matcher.match(canonical), matches,
+            "File %s should have matched as %s" % (filepath, matches)
+        )
+
     def test_tree_matcher(self):
-        file1 = self.make_file("sub/file1.py")
-        file2 = self.make_file("sub/file2.c")
-        file3 = self.make_file("sub2/file3.h")
-        file4 = self.make_file("sub3/file4.py")
-        file5 = self.make_file("sub3/file5.c")
+        matches_to_try = [
+            (self.make_file("sub/file1.py"), True),
+            (self.make_file("sub/file2.c"), True),
+            (self.make_file("sub2/file3.h"), False),
+            (self.make_file("sub3/file4.py"), True),
+            (self.make_file("sub3/file5.c"), False),
+        ]
         fl = FileLocator()
         trees = [
             fl.canonical_filename("sub"),
-            fl.canonical_filename(file4),
+            fl.canonical_filename("sub3/file4.py"),
             ]
         tm = TreeMatcher(trees)
-        self.assertTrue(tm.match(fl.canonical_filename(file1)))
-        self.assertTrue(tm.match(fl.canonical_filename(file2)))
-        self.assertFalse(tm.match(fl.canonical_filename(file3)))
-        self.assertTrue(tm.match(fl.canonical_filename(file4)))
-        self.assertFalse(tm.match(fl.canonical_filename(file5)))
-
         self.assertEqual(tm.info(), trees)
+        for filepath, matches in matches_to_try:
+            self.assertMatches(tm, filepath, matches)
 
     def test_fnmatch_matcher(self):
-        file1 = self.make_file("sub/file1.py")
-        file2 = self.make_file("sub/file2.c")
-        file3 = self.make_file("sub2/file3.h")
-        file4 = self.make_file("sub3/file4.py")
-        file5 = self.make_file("sub3/file5.c")
+        matches_to_try = [
+            (self.make_file("sub/file1.py"), True),
+            (self.make_file("sub/file2.c"), False),
+            (self.make_file("sub2/file3.h"), True),
+            (self.make_file("sub3/file4.py"), True),
+            (self.make_file("sub3/file5.c"), False),
+        ]
         fl = FileLocator()
         fnm = FnmatchMatcher(["*.py", "*/sub2/*"])
-        self.assertTrue(fnm.match(fl.canonical_filename(file1)))
-        self.assertFalse(fnm.match(fl.canonical_filename(file2)))
-        self.assertTrue(fnm.match(fl.canonical_filename(file3)))
-        self.assertTrue(fnm.match(fl.canonical_filename(file4)))
-        self.assertFalse(fnm.match(fl.canonical_filename(file5)))
-
         self.assertEqual(fnm.info(), ["*.py", "*/sub2/*"])
+        for filepath, matches in matches_to_try:
+            self.assertMatches(fnm, filepath, matches)
 
 
 class PathAliasesTest(CoverageTest):