add tests related to snapshots

test_zfs_backup.py

@@ -1,6 +1,8 @@
 import pytest
 
-from zfs_backup import ZFSPath
+from unittest import mock
+
+from zfs_backup import ZFSPath, Dataset, Snapshot
 
 
 class TestZFSPath:
@@ -156,3 +158,28 @@ class TestZFSPath:
     )
     def test_replace_pool(self, instance1, instance2):
         assert instance1.replace_pool(instance2.pool_name) == instance2
+
+
+class TestZFS:
+    @pytest.mark.parametrize("string", ["tank", "tank/ROOT", "tank/ROOT/default"])
+    def test_get_snapshots(self, string):
+        path = ZFSPath.from_string(string)
+        ds = Dataset(path)
+        for snapshot in ds.snapshots:
+            assert snapshot.dataset == ds
+
+
+class TestDataset:
+    @pytest.mark.parametrize("zfspath", ["tank", "tank/ROOT", "tank/ROOT/default"])
+    def test__clean_old_snapshots_for_interval(self, zfspath):
+        """Check that only snapshots that are direct children of the dataset are found during cleanup."""
+
+        def validate_snapshot_selection(snapshot: Snapshot):
+            print(snapshot)  # show output with "pytest -s"
+            str(snapshot).startswith(f"{zfspath}@")
+
+        dataset = Dataset(ZFSPath.from_string(zfspath))
+        with mock.patch.object(
+            Snapshot, "destroy", lambda snapshot: validate_snapshot_selection(snapshot)
+        ):
+            dataset._clean_old_snapshots_for_interval("daily", 999)