Fix Wagtail article publish regressions

apps/blog/tests/test_models.py

@@ -59,6 +59,32 @@ def test_article_default_category_is_assigned(home_page):
     assert article.category.slug == "general"
 
 
+@pytest.mark.django_db
+def test_article_read_time_is_not_recomputed_when_body_text_is_unchanged(home_page, monkeypatch):
+    index = ArticleIndexPage(title="Articles", slug="articles")
+    home_page.add_child(instance=index)
+    author = AuthorFactory()
+    article = ArticlePage(
+        title="Stable read time",
+        slug="stable-read-time",
+        author=author,
+        summary="s",
+        body=[("rich_text", "<p>body words</p>")],
+    )
+    index.add_child(instance=article)
+    article.save()
+
+    def fail_compute():
+        raise AssertionError("read time should not be recomputed when body text is unchanged")
+
+    monkeypatch.setattr(article, "_compute_read_time", fail_compute)
+    article.title = "Retitled"
+    article.save()
+    article.refresh_from_db()
+
+    assert article.read_time_mins == 1
+
+
 @pytest.mark.django_db
 def test_category_ordering():
     Category.objects.get_or_create(name="General", slug="general")