TEST: Applying dump upgrade script twice fails.

dump_updates/test/test_all.py

@@ -19,6 +19,11 @@
 # along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 """Testing the dump update scripts
+
+As a general rule, dump updaters should be idempotent, so tests should run the update again after
+the first checks are successlful.
+
+TODO: Reduce the boilerplate for the tests.
 """
 
 import filecmp
@@ -68,3 +73,13 @@ def test_2024_10_02(tmpdir):
                 check=True
                 )
             assert filecmp.cmp(output.name, expectedfile), "Output does not match expected output."
+            with (NamedTemporaryFile(dir=tmpdir, suffix=".sql", delete=True) as output2,
+                  open(output.name, mode="rb") as infile_stream
+                  ):
+                run([script_fullname],
+                    stdin=infile_stream,
+                    stdout=output2,
+                    check=True
+                    )
+                assert filecmp.cmp(output2.name, expectedfile), (
+                    "Run 2: Output does not match expected output.")