creat unit test for __all__ (#599)

tests/test___all__.py

@@ -0,0 +1,25 @@
+import re
+import sys
+
+from os import walk
+from collections import Counter
+
+
+FILE_PATTERN = "^(?!_).*\.py$"
+SOUCE_CODE_ROOT = "osxphotos"
+
+def create_module_name(dirpath: str, filename: str) -> str:
+    prefix = dirpath[dirpath.rfind(SOUCE_CODE_ROOT):].replace('/', '.')
+    return f"{prefix}.{filename}".replace(".py", "")
+
+
+def test_check_duplicate():
+    for dirpath, dirnames, filenames in walk(SOUCE_CODE_ROOT):
+        print("\n", sys.modules)
+        for filename in filenames:
+            if re.search(FILE_PATTERN, filename):
+                module = create_module_name(dirpath, filename)
+                if module in sys.modules:
+                    all_list = sys.modules[module].__all__
+                    all_set = set(all_list)
+                    assert Counter(all_list) == Counter(all_set)