os.path: Implement isdir().

os.path/os/path.py

@@ -27,3 +27,11 @@ def exists(path):
 
 # TODO
 lexists = exists
+
+def isdir(path):
+    import stat
+    try:
+        mode = os.stat(path)[0]
+        return stat.S_ISDIR(mode)
+    except OSError:
+        return False

os.path/test_path.py

@@ -6,3 +6,10 @@ assert split("/") == ("/", "")
 assert split("/foo") == ("/", "foo")
 assert split("/foo/") == ("/foo", "")
 assert split("/foo/bar") == ("/foo", "bar")
+
+assert exists("test_path.py")
+assert not exists("test_path.py--")
+
+assert isdir("os")
+assert not isdir("os--")
+assert not isdir("test_path.py")