Fix #687: Ensure calendar versioning tests use a consistent time contex

- prevent failures around midnight in non-UTC timezones
- Update `meta` function to accept a time parameter for consistent behaviour in tests

Author: RonnyPfannschmidt

CHANGELOG.md

@@ -16,6 +16,7 @@
 ### Fixed
 
 - fix #1145: ensure GitWorkdir.get_head_date returns consistent UTC dates regardless of local timezone
+- fix #687: ensure calendar versioning tests use consistent time context to prevent failures around midnight in non-UTC timezones
 - reintroduce Python 3.9 entrypoints shim for compatibility
 - fix #1136: update customizing.md to fix missing import
 

src/setuptools_scm/version.py

@@ -212,11 +212,12 @@ def meta(
     branch: str | None = None,
     config: _config.Configuration,
     node_date: date | None = None,
+    time: datetime | None = None,
 ) -> ScmVersion:
     parsed_version = _parse_tag(tag, preformatted, config)
     log.info("version %s -> %s", tag, parsed_version)
     assert parsed_version is not None, f"Can't parse version {tag}"
-    return ScmVersion(
+    scm_version = ScmVersion(
         parsed_version,
         distance=distance,
         node=node,
@@ -226,6 +227,9 @@ def meta(
         config=config,
         node_date=node_date,
     )
+    if time is not None:
+        scm_version = dataclasses.replace(scm_version, time=time)
+    return scm_version
 
 
 def guess_next_version(tag_version: ScmVersion) -> str:
@@ -365,19 +369,25 @@ def guess_next_date_ver(
     head_date = node_date or today
     # compute patch
     if match is None:
-        tag_date = today
+        # For legacy non-date tags, always use patch=0 (treat as "other day")
+        # Use yesterday to ensure tag_date != head_date
+        from datetime import timedelta
+
+        tag_date = head_date - timedelta(days=1)
     else:
         tag_date = (
             datetime.strptime(match.group("date"), date_fmt)
             .replace(tzinfo=timezone.utc)
             .date()
         )
     if tag_date == head_date:
-        patch = "0" if match is None else (match.group("patch") or "0")
-        patch = int(patch) + 1
+        assert match is not None
+        # Same day as existing date tag - increment patch
+        patch = int(match.group("patch") or "0") + 1
     else:
+        # Different day or legacy non-date tag - use patch 0
         if tag_date > head_date and match is not None:
-            # warn on future times
+            # warn on future times (only for actual date tags, not legacy)
             warnings.warn(
                 f"your previous tag  ({tag_date}) is ahead your node date ({head_date})"
             )

testing/test_version.py

@@ -2,7 +2,9 @@
 
 from dataclasses import replace
 from datetime import date
+from datetime import datetime
 from datetime import timedelta
+from datetime import timezone
 from typing import Any
 
 import pytest
@@ -269,11 +271,14 @@ def test_custom_version_schemes() -> None:
     assert custom_computed == no_guess_dev_version(version)
 
 
+# Fixed time for consistent test behavior across timezone boundaries
+# This prevents issue #687 where tests failed around midnight in non-UTC timezones
+_TEST_TIME = datetime(2023, 12, 15, 12, 0, 0, tzinfo=timezone.utc)
+
+
 def date_offset(base_date: date | None = None, days_offset: int = 0) -> date:
     if base_date is None:
-        from setuptools_scm.version import _source_epoch_or_utc_now
-
-        base_date = _source_epoch_or_utc_now().date()
+        base_date = _TEST_TIME.date()
     return base_date - timedelta(days=days_offset)
 
 
@@ -304,12 +309,23 @@ def date_to_str(
             id="leading 0s",
         ),
         pytest.param(
-            meta(date_to_str(days_offset=3), config=c_non_normalize, dirty=True),
+            meta(
+                date_to_str(days_offset=3),
+                config=c_non_normalize,
+                dirty=True,
+                time=_TEST_TIME,
+            ),
             date_to_str() + ".0.dev0",
             id="dirty other day",
         ),
         pytest.param(
-            meta(date_to_str(), config=c_non_normalize, distance=2, branch="default"),
+            meta(
+                date_to_str(),
+                config=c_non_normalize,
+                distance=2,
+                branch="default",
+                time=_TEST_TIME,
+            ),
             date_to_str() + ".1.dev2",
             id="normal branch",
         ),
@@ -382,8 +398,8 @@ def test_calver_by_date(version: ScmVersion, expected_next: str) -> None:
     [
         pytest.param(meta("1.0.0", config=c), "1.0.0", id="SemVer exact stays"),
         pytest.param(
-            meta("1.0.0", config=c_non_normalize, dirty=True),
-            "09.02.13.1.dev0",
+            meta("1.0.0", config=c_non_normalize, dirty=True, time=_TEST_TIME),
+            "23.12.15.0.dev0",
             id="SemVer dirty is replaced by date",
             marks=pytest.mark.filterwarnings("ignore:.*legacy version.*:UserWarning"),
         ),
@@ -397,7 +413,12 @@ def test_calver_by_date_semver(version: ScmVersion, expected_next: str) -> None:
 def test_calver_by_date_future_warning() -> None:
     with pytest.warns(UserWarning, match="your previous tag*"):
         calver_by_date(
-            meta(date_to_str(days_offset=-2), config=c_non_normalize, distance=2)
+            meta(
+                date_to_str(days_offset=-2),
+                config=c_non_normalize,
+                distance=2,
+                time=_TEST_TIME,
+            )
         )