Add tests for quarterly pruning strategy.

src/borg/testsuite/archiver.py

@@ -2314,6 +2314,76 @@ def test_prune_repository_example(self):
         for i in range(22, 25):
             self.assert_not_in('test%02d' % i, output)
 
+    def test_prune_quarterly(self):
+        # Example worked through by hand when developing quarterly
+        # strategy, based upon existing backups where quarterly strategy
+        # is desired. Weekly/monthly backups that don't affect results were
+        # trimmed to speed up the test.
+        #
+        # Week number is shown in comment for every row in the below list.
+        # Year is also shown when it doesn't match the year given in the
+        # date tuple.
+        test_dates = [
+                (2020, 12, 6), (2021, 1, 3),   # 49, 2020-53
+                (2021, 3, 28), (2021, 4, 25),  # 12, 16
+                (2021, 6, 27), (2021, 7, 4),   # 25, 26
+                (2021, 9, 26), (2021, 10, 3),  # 38, 39
+                (2021, 12, 26), (2022, 1, 2)   # 51, 2021-52
+        ]
+
+        def mk_name(tup):
+            (y, m, d) = tup
+            suff = datetime(y, m, d).strftime("%Y-%m-%d")
+            return f"test-{suff}"
+
+        # The kept repos are based on working on an example by hand,
+        # archives made on the following dates should be kept:
+        EXPECTED_KEPT = {
+            "13weekly": [
+                (2020, 12, 6), (2021, 1, 3), (2021, 3, 28), (2021, 7, 4),
+                (2021, 10, 3), (2022, 1, 2)
+            ],
+            "3monthly": [
+                (2020, 12, 6), (2021, 3, 28), (2021, 6, 27), (2021, 9, 26),
+                (2021, 12, 26), (2022, 1, 2)
+            ]
+        }
+
+        for (strat, to_keep) in EXPECTED_KEPT.items():
+            # Initialize our repo.
+            self.cmd('init', '--encryption=repokey', self.repository_location)
+            for a, (y, m, d) in zip(map(mk_name, test_dates), test_dates):
+                self._create_archive_ts(a, y, m, d)
+
+            to_prune = list(set(test_dates) - set(to_keep))
+
+            # Use 99 instead of -1 to test that oldest backup is kept.
+            output = self.cmd('prune', '--list', '--dry-run', self.repository_location, f"--keep-{strat}=99")
+            for a in map(mk_name, to_prune):
+                assert re.search(fr"Would prune:\s+{a}", output)
+
+            oldest = r"\[oldest\]" if strat in ("13weekly") else ""
+            assert re.search(fr"Keeping archive \(rule: quarterly_{strat}{oldest} #\d+\):\s+test-2020-12-06", output)
+            for a in map(mk_name, to_keep[1:]):
+                assert re.search(fr"Keeping archive \(rule: quarterly_{strat} #\d+\):\s+{a}", output)
+
+            output = self.cmd('list', self.repository_location)
+            # Nothing pruned after dry run
+            for a in map(mk_name, test_dates):
+                self.assert_in(a, output)
+
+            self.cmd('prune', self.repository_location, f"--keep-{strat}=99")
+            output = self.cmd('list', self.repository_location)
+            # All matching backups plus oldest kept
+            for a in map(mk_name, to_keep):
+                self.assert_in(a, output)
+            # Other backups have been pruned
+            for a in map(mk_name, to_prune):
+                self.assert_not_in(a, output)
+
+            # Delete repo and begin anew
+            self.cmd('delete', self.repository_location)
+
     # With an initial and daily backup, prune daily until oldest is replaced by a monthly backup
     def test_prune_retain_and_expire_oldest(self):
         self.cmd('init', '--encryption=repokey', self.repository_location)