Add tests for the names of migration files

Author: ewjoachim

tests/migration/test_migration.py

@@ -1,9 +1,12 @@
 from __future__ import annotations
 
 import contextlib
+import os
 import pathlib
+import subprocess
 import warnings
 
+import packaging.version
 import pytest
 from django.core import management
 from django.db import connection
@@ -98,3 +101,93 @@ def test_django_migrations_run_properly(django_db):
 
 def test_no_missing_django_migration(django_db):
     management.call_command("makemigrations", "procrastinate", dry_run=True, check=True)
+
+
+@pytest.fixture(scope="module")
+def latest_version() -> packaging.version.Version:
+    if latest_tag := os.environ.get("LATEST_TAG"):
+        return packaging.version.Version(latest_tag)
+
+    if "CI" in os.environ:
+        raise ValueError("Cannot fetch latest tag in CI unless LATEST_TAG is set")
+
+    # If we're not in the CI, we can accept loosing a bit of time to fetch the latest tag
+    try:
+        subprocess.check_call(["git", "fetch", "--tags"])
+        out = subprocess.check_output(["git", "tag", "--list"], text=True)
+    except subprocess.CalledProcessError as exc:
+        raise ValueError("Cannot fetch latest tag") from exc
+
+    return max(packaging.version.Version(tag) for tag in out.splitlines())
+
+
+migration_files = sorted(
+    (pathlib.Path(__file__).parents[2] / "procrastinate" / "sql" / "migrations").glob(
+        "*.sql"
+    )
+)
+
+
+@pytest.fixture(scope="module")
+def new_migrations(latest_version) -> set[pathlib.Path]:
+    # git diff latest_version..HEAD --name-only --diff-filter=A
+
+    try:
+        out = subprocess.check_output(
+            [
+                "git",
+                "diff",
+                f"{latest_version}..HEAD",
+                "--name-only",
+                "--diff-filter=A",
+            ],
+            text=True,
+        )
+    except subprocess.CalledProcessError as exc:
+        raise ValueError("Cannot fetch new migrations") from exc
+
+    return {pathlib.Path(path) for path in out.splitlines()}
+
+
+@pytest.mark.parametrize(
+    "migration", [pytest.param(m, id=m.name) for m in migration_files]
+)
+def test_migration_properly_named(
+    migration: pathlib.Path,
+    latest_version: packaging.version.Version,
+    new_migrations: set[pathlib.Path],
+):
+    # migration is:
+    # pathlib.Path("..." / "03.00.00_01_pre_cancel_notification.sql")
+
+    migration_name_parts = migration.stem.split("_", 3)
+    version_str, index_str, *pre_post_name = migration_name_parts
+
+    mig_version = packaging.version.Version(version_str)
+
+    next_minor = packaging.version.Version(
+        f"{latest_version.major}.{latest_version.minor + 1}.0"
+    )
+
+    if migration in new_migrations:
+        assert mig_version == next_minor
+    else:
+        assert mig_version <= latest_version
+
+    if mig_version < packaging.version.Version("3.0.0"):
+        pre_post = "pre"
+        name = pre_post_name[0]
+    else:
+        pre_post, name = pre_post_name
+
+    index = int(index_str)
+    if pre_post == "pre":
+        assert 1 <= index < 50
+    elif pre_post == "post":
+        assert 50 <= index
+    else:
+        assert False, f"Invalid migration name: expecting 'pre' or 'post': {pre_post}"
+
+    assert name == name.lower()
+    assert "-" not in name
+    assert " " not in name