Fix.

tests/test_cache.py

@@ -19,6 +19,12 @@ def __init__(self, is_file=False):
                 self.st_dev = 0
                 self.st_mode = stat.S_IFREG if is_file else stat.S_IFDIR
 
+            def isdir(self):
+                return self.st_mode == stat.S_IFDIR
+
+            def isfile(self):
+                return self.st_mode == stat.S_IFREG
+
         class Stat:
             def __init__(self, directories, files):
                 self.__filesystem = {}
@@ -71,9 +77,19 @@ def mock_open(path):
             except KeyError:
                 raise FileNotFoundError()
 
-        def mock_stat(path):
-            statistics["stat"] += 1
-            return my_stat(path)
+        def mock_isdir(path):
+            statistics["isdir"] += 1
+            try:
+                return my_stat(path).isdir()
+            except FileNotFoundError:
+                return False
+
+        def mock_isfile(path):
+            statistics["isfile"] += 1
+            try:
+                return my_stat(path).isfile()
+            except FileNotFoundError:
+                return False
 
         data = {
             "/home/vladimir/project/directory/subdirectory/file.txt": True,
@@ -84,20 +100,22 @@ def mock_stat(path):
             "/home/vladimir/project/directory/file.txt": True,
             "/home/vladimir/project/directory/file2.txt": True,
             "/home/vladimir/project/file.txt": False,
-            "/home/vladimir/file.txt": False,  # No rules and no `stat` calls for this file.
+            "/home/vladimir/file.txt": False,  # No rules and no `isdir` calls for this file.
         }
 
         for permutation in itertools.islice(itertools.permutations(data.items()), 0, None, 100):
-            statistics = {"open": 0, "stat": 0}
+            statistics = {"open": 0, "isdir": 0, "isfile": 0}
 
             with unittest.mock.patch("builtins.open", mock_open):
-                with unittest.mock.patch("os.stat", mock_stat):
-                    matches = gitignorefile.Cache()
-                    for path, expected in permutation:
-                        self.assertEqual(matches(path), expected)
+                with unittest.mock.patch("os.path.isdir", mock_isdir):
+                    with unittest.mock.patch("os.path.isfile", mock_isfile):
+                        matches = gitignorefile.Cache()
+                        for path, expected in permutation:
+                            self.assertEqual(matches(path), expected)
 
             self.assertEqual(statistics["open"], 2)
-            self.assertEqual(statistics["stat"], 7 + 9 - 1)
+            self.assertEqual(statistics["isdir"], len(data) - 1)
+            self.assertEqual(statistics["isfile"], 7)  # Unique path fragments.
 
     def test_wrong_symlink(self):
         with tempfile.TemporaryDirectory() as d: