Add a consistent digest and tests

tests/ci/digest_helper.py

@@ -46,7 +46,7 @@ def digest_path(path: Path, hash_object: Optional[HASH] = None) -> HASH:
 
 def digest_paths(paths: Iterable[Path], hash_object: Optional[HASH] = None) -> HASH:
     """Calculates aggregated md5 (or updates existing hash_object) hash of passed paths.
-    The order matters"""
+    The order is processed as given"""
     hash_object = hash_object or md5()
     for path in paths:
         if path.exists():
@@ -54,6 +54,15 @@ def digest_paths(paths: Iterable[Path], hash_object: Optional[HASH] = None) -> H
     return hash_object
 
 
+def digest_consistent_paths(
+    paths: Iterable[Path], hash_object: Optional[HASH] = None
+) -> HASH:
+    """Calculates aggregated md5 (or updates existing hash_object) hash of passed paths.
+    The order doesn't matter, paths are converted to `absolute` and ordered before
+    calculation"""
+    return digest_paths(sorted(p.absolute() for p in paths), hash_object)
+
+
 def digest_script(path_str: str) -> HASH:
     """Accepts value of the __file__ executed script and calculates the md5 hash for it"""
     path = Path(path_str)

tests/ci/test_digest.py

@@ -0,0 +1,139 @@
+#!/usr/bin/env python
+
+import unittest
+from hashlib import md5
+from pathlib import Path
+
+import digest_helper as dh
+
+_12 = b"12\n"
+_13 = b"13\n"
+
+
+# pylint:disable=protected-access
+class TestDigests(unittest.TestCase):
+    tests_dir = Path("tests/digests")
+    broken_link = tests_dir / "broken-symlink"
+    empty_digest = "d41d8cd98f00b204e9800998ecf8427e"
+
+    def test__digest_file(self):
+        hash_tested = md5()
+        with self.assertRaises(
+            AssertionError, msg="_digest_file shouldn't work with dirs"
+        ):
+            dh._digest_file(self.tests_dir, hash_tested)
+        with self.assertRaises(
+            AssertionError, msg="_digest_file shouldn't work with broken links"
+        ):
+            dh._digest_file(self.broken_link, hash_tested)
+
+        # file with content '12\n'
+        hash_expected = md5()
+        hash_expected.update(_12)
+        dh._digest_file(self.tests_dir / "12", hash_tested)
+        self.assertEqual(hash_expected.digest(), hash_tested.digest())
+        # symlink to '12\n'
+        hash_tested = md5()
+        dh._digest_file(self.tests_dir / "symlink-12", hash_tested)
+        self.assertEqual(hash_expected.digest(), hash_tested.digest())
+
+    def test__digest_directory(self):
+        hash_tested = md5()
+        with self.assertRaises(
+            AssertionError, msg="_digest_directory shouldn't work with files"
+        ):
+            dh._digest_directory(self.tests_dir / "12", hash_tested)
+        with self.assertRaises(
+            AssertionError, msg="_digest_directory shouldn't work with broken links"
+        ):
+            dh._digest_file(self.broken_link, hash_tested)
+
+        # dir1
+        hash_expected = md5()
+        hash_expected.update(_12)
+        dh._digest_directory(self.tests_dir / "dir1", hash_tested)
+        self.assertEqual(hash_expected.digest(), hash_tested.digest())
+
+        # dir2 contains 12 and 13
+        hash_expected.update(_13)
+        hash_tested = md5()
+        dh._digest_directory(self.tests_dir / "dir2", hash_tested)
+        self.assertEqual(hash_expected.digest(), hash_tested.digest())
+
+        # dir3 is symlink to dir2
+        hash_tested = md5()
+        dh._digest_directory(self.tests_dir / "dir3", hash_tested)
+        self.assertEqual(hash_expected.digest(), hash_tested.digest())
+
+    def test_digest_path(self):
+        # test broken link does nothing
+        self.assertEqual(
+            self.empty_digest, dh.digest_path(self.broken_link).hexdigest()
+        )
+        # Test file works fine
+        hash_expected = md5()
+        hash_expected.update(_12)
+        self.assertEqual(
+            hash_expected.digest(), dh.digest_path(self.tests_dir / "12").digest()
+        )
+        # Test directory works fine
+        hash_expected = md5()
+        hash_expected.update(_12)
+        self.assertEqual(
+            hash_expected.digest(), dh.digest_path(self.tests_dir / "dir1").digest()
+        )
+        # Test existed hash is updated from symlink dir3
+        hash_tested = hash_expected.copy()
+        dh.digest_path(self.tests_dir / "dir3", hash_tested)
+        hash_expected = md5()
+        hash_expected.update(_12 + _12 + _13)
+        self.assertEqual(hash_expected.digest(), hash_tested.digest())
+        # Test the full content of the following structure
+        # tests/digests
+        # ├── 12
+        # ├── dir1
+        # │   └── 12
+        # ├── dir2
+        # │   ├── 12
+        # │   └── 13
+        # ├── dir3 -> dir2
+        # └── symlink-12 -> 12
+        hash_expected = md5()
+        hash_expected.update(_12 * 3 + (_13 + _12) * 2)
+        self.assertEqual(
+            hash_expected.digest(), dh.digest_path(self.tests_dir).digest()
+        )
+
+    def test_digest_paths(self):
+        # test paths order matters
+        hash_ordered = dh.digest_paths(
+            (self.tests_dir / d for d in ("dir1", "dir2", "dir3"))
+        )
+        hash_reversed = dh.digest_paths(
+            (self.tests_dir / d for d in ("dir3", "dir2", "dir1"))
+        )
+        hash_unordered = dh.digest_paths(
+            (self.tests_dir / d for d in ("dir3", "dir1", "dir2"))
+        )
+        self.assertNotEqual(hash_ordered.digest(), hash_unordered.digest())
+        self.assertNotEqual(hash_ordered.digest(), hash_reversed.digest())
+        self.assertNotEqual(hash_unordered.digest(), hash_reversed.digest())
+
+    def test_digest_consistent_paths(self):
+        # test paths order does not matter
+        hash_ordered = dh.digest_consistent_paths(
+            (self.tests_dir / d for d in ("dir1", "dir2", "dir3"))
+        )
+        hash_reversed = dh.digest_consistent_paths(
+            (self.tests_dir / d for d in ("dir3", "dir2", "dir1"))
+        )
+        self.assertEqual(hash_ordered.digest(), hash_reversed.digest())
+
+    @classmethod
+    def setUpClass(cls):
+        # create a broken symlink
+        (TestDigests.broken_link).symlink_to("non-existent-link")
+
+    @classmethod
+    def tearDownClass(cls):
+        (TestDigests.broken_link).unlink()

tests/ci/tests/digests/12

@@ -0,0 +1 @@
+12

tests/ci/tests/digests/dir1/12

@@ -0,0 +1 @@
+12

tests/ci/tests/digests/dir2/12

@@ -0,0 +1 @@
+12

tests/ci/tests/digests/dir2/13

@@ -0,0 +1 @@
+13

tests/ci/tests/digests/dir3

@@ -0,0 +1 @@
+dir2

tests/ci/tests/digests/symlink-12

@@ -0,0 +1 @@
+12