Allow for means of iteration through Snapshots in a Repository

rbackup/hierarchy/repository.py

@@ -48,6 +48,11 @@ class Repository(Hierarchy):
       * rsync hardlinks unchanged files between snapshots
     * A symlink in the root of the repository symlinking to the
       most recent snapshot
+
+    Iteration
+    ---------
+    To support checking all snapshots for hardlinking, the Repository class
+    can be iterated through.
     """
 
     def __init__(self, dest):
@@ -65,10 +70,25 @@ class Repository(Hierarchy):
             self._curr_snapshot = self._snapshots[-1]
 
     def __len__(self):
-        return len(self._snapshots)
+        """Return the number of snapshots in this Repository."""
+        return len(self.snapshots)
 
     def __getitem__(self, position):
-        return self._snapshots[position]
+        """Retrieve a Snapshot at a certain index."""
+        return self.snapshots[position]
+
+    def __iter__(self):
+        self.snapshot_index = 0
+        return self
+
+    def __next__(self):
+        """Return the next Snapshot in this Repository."""
+        try:
+            result = self.snapshots[self.snapshot_index]
+            self.snapshot_index += 1
+            return result
+        except IndexError:
+            raise StopIteration
 
     @property
     def snapshots(self):
@@ -98,6 +118,9 @@ class Repository(Hierarchy):
         >>> repo = Repository('/tmp')
         >>> repo.empty
         True
+        >>> repo.create_snapshot()
+        >>> repo.empty
+        False
 
         :rtype: bool
         """

tests/test_repository.py

@@ -17,6 +17,54 @@ def load_tests(loader, tests, ignore):
 
 
 # ========== Integration Tests ==========
+class TestEmptyRepository(unittest.TestCase):
+    def setUp(self):
+        self.patched_snapshots = patch(
+            f"{TESTING_MODULE}.Repository.snapshots", new_callable=PropertyMock
+        )
+        self.mocked_snapshots = self.patched_snapshots.start()
+        self.mocked_snapshots.return_value = list()
+
+        self.repo_basepath = "backup"
+        self.repo = Repository(self.repo_basepath)
+
+    def test_curr_snapshot_pre_create(self):
+        self.assertIsNone(self.repo.curr_snapshot)
+        self.assertEqual(len(self.repo), 0)
+
+    def test_iteration_pre_create(self):
+        result = list()
+        for snapshot in self.repo:
+            result.append(snapshot.path)
+
+        self.assertListEqual(result, [])
+
+    def test_subscript_pre_create(self):
+        with self.assertRaises(IndexError):
+            self.assertRaises(IndexError, self.repo[0])
+
+    def test_curr_snapshot_post_create(self):
+        snapshot_name = "new"
+        new_snapshot = Snapshot(f"backup/data/snapshot-{snapshot_name}")
+
+        self.repo.create_snapshot(snapshot_name)
+        self.assertEqual(self.repo.curr_snapshot.path, new_snapshot.path)
+        self.assertEqual(len(self.repo), 1)
+        self.assertIsInstance(self.repo.curr_snapshot, Snapshot)
+
+        result = list()
+        for snapshot in self.repo:
+            result.append(snapshot.path)
+
+        self.assertListEqual(result, [PosixPath("backup/data/snapshot-new")])
+
+        self.assertEqual(self.repo[0], self.repo.curr_snapshot)
+        self.assertEqual(self.repo[-1], self.repo.curr_snapshot)
+
+    def tearDown(self):
+        self.patched_snapshots.stop()
+
+
 class TestPopulatedRepository(unittest.TestCase):
     def setUp(self):
         self.snapshots = [
@@ -29,7 +77,7 @@ class TestPopulatedRepository(unittest.TestCase):
             f"{TESTING_MODULE}.Repository.snapshots", new_callable=PropertyMock
         )
         self.mocked_snapshots = self.patched_snapshots.start()
-        self.mocked_snapshots.return_value = self.snapshots
+        self.mocked_snapshots.return_value = list(self.snapshots)
 
         self.repo_basepath = "backup"
         self.repo = Repository(self.repo_basepath)
@@ -37,47 +85,47 @@ class TestPopulatedRepository(unittest.TestCase):
     def test_snapshots(self):
         found_snapshots = [s for s in self.repo.snapshots]
         self.assertListEqual(found_snapshots, self.snapshots)
+        self.assertEqual(len(self.repo), len(self.snapshots))
 
     def test_curr_snapshot_pre_create(self):
         snapshot_name = "third"
         last_snapshot = Snapshot(f"backup/data/snapshot-{snapshot_name}")
 
         self.assertEqual(self.repo.curr_snapshot.path, last_snapshot.path)
+        self.assertEqual(len(self.repo), len(self.snapshots))
         self.assertIsInstance(self.repo.curr_snapshot, Snapshot)
 
+    def test_iteration_pre_create(self):
+        result = list()
+        for snapshot in self.repo:
+            result.append(snapshot)
+
+        self.assertListEqual(result, self.snapshots)
+
+    def test_subscript_pre_create(self):
+        self.assertEqual(self.repo[0], self.snapshots[0])
+        self.assertEqual(self.repo[-1], self.snapshots[-1])
+        self.assertEqual(self.repo[len(self.repo) - 1], self.snapshots[-1])
+
     def test_curr_snapshot_post_create(self):
         snapshot_name = "new"
         snapshot_path = PosixPath(f"backup/data/snapshot-{snapshot_name}")
 
         self.repo.create_snapshot(snapshot_name)
         self.assertEqual(self.repo.curr_snapshot.path, snapshot_path)
+        self.assertEqual(len(self.repo), len(self.snapshots) + 1)
         self.assertIsInstance(self.repo.curr_snapshot, Snapshot)
-
+
-    def tearDown(self):
+    def test_iteration_post_create(self):
-        self.patched_snapshots.stop()
+        result = list()
-
+        for snapshot in self.repo:
-
+            result.append(snapshot)
-class TestEmptyRepository(unittest.TestCase):
+
-    def setUp(self):
+        self.assertListEqual(result, self.snapshots)
-        self.patched_snapshots = patch(
+
-            f"{TESTING_MODULE}.Repository.snapshots", new_callable=PropertyMock
+    def test_subscript_post_create(self):
-        )
+        self.assertEqual(self.repo[0], self.snapshots[0])
-        self.mocked_snapshots = self.patched_snapshots.start()
+        self.assertEqual(self.repo[-1], self.repo.curr_snapshot)
-        self.mocked_snapshots.return_value = []
-
-        self.repo_basepath = "backup"
-        self.repo = Repository(self.repo_basepath)
-
-    def test_curr_snapshot_pre_create(self):
-        self.assertIsNone(self.repo.curr_snapshot)
-
-    def test_curr_snapshot_post_create(self):
-        snapshot_name = "new"
-        new_snapshot = Snapshot(f"backup/data/snapshot-{snapshot_name}")
-
-        self.repo.create_snapshot(snapshot_name)
-        self.assertEqual(self.repo.curr_snapshot.path, new_snapshot.path)
-        self.assertIsInstance(self.repo.curr_snapshot, Snapshot)
 
     def tearDown(self):
         self.patched_snapshots.stop()