Accommodate tables with no rows

Tables with no rows are not semantically correct, but they shouldn't
crash the app.

Now they don't crash the app, amazing. 🙌

CHANGELOG.md

@@ -20,6 +20,7 @@ The format is based on Keep a Changelog, and this project adheres to Semantic Ve
 
 - Do not bold paragraph in th that follows a strong
 - Add 33% and 66% width classes
+- Tables with no rows no longer crash the app
 
 ## [1.36.0] - 2023-11-19
 

bloom_nofos/nofos/templatetags/utils/__init__.py

@@ -226,16 +226,19 @@ def get_parent_td(element):
 
 def is_callout_box_table_markdown(table):
     rows = table.find_all("tr")
-    cols = rows[0].find_all("th") + rows[0].find_all("td")
-    tds = table.find_all("td")
+    if rows:
+        cols = rows[0].find_all("th") + rows[0].find_all("td")
+        tds = table.find_all("td")
+
+        return (
+            len(cols) == 1  # 1 column
+            and len(rows) == 2  # 2 rows (thead and tbody generated automatically)
+            and len(tds) == 1  # 1 cell
+            and tds[0]
+            and tds[0].get_text().strip() == ""  # the cell is empty
+        )
 
-    return (
-        len(cols) == 1  # 1 column
-        and len(rows) == 2  # 2 rows (thead and tbody generated automatically)
-        and len(tds) == 1  # 1 cell
-        and tds[0]
-        and tds[0].get_text().strip() == ""  # the cell is empty
-    )
+    return False
 
 
 # Footnotes

bloom_nofos/nofos/tests/test_templatetags.py

@@ -17,6 +17,7 @@
     format_footnote_ref_html,
     get_footnote_type,
     get_parent_td,
+    is_callout_box_table_markdown,
     is_floating_callout_box,
     is_footnote_ref,
 )
@@ -267,6 +268,75 @@ def test_edge_case_just_over_225(self):
         self.assertEqual(result, "nofo--cover-page--title--h1--very-very-smol")
 
 
+class IsCalloutBoxTableMarkdownTest(TestCase):
+    def test_valid_callout_box_table(self):
+        # A table with 1 column, 2 rows, and 1 empty cell
+        html = """
+        <table>
+            <tr><th>Header</th></tr>
+            <tr><td></td></tr>
+        </table>
+        """
+        soup = BeautifulSoup(html, "html.parser")
+        table = soup.find("table")
+        self.assertTrue(is_callout_box_table_markdown(table))
+
+    def test_invalid_multiple_columns(self):
+        # A table with more than 1 column
+        html = """
+        <table>
+            <tr><th>Header 1</th><th>Header 2</th></tr>
+            <tr><td></td></tr>
+        </table>
+        """
+        soup = BeautifulSoup(html, "html.parser")
+        table = soup.find("table")
+        self.assertFalse(is_callout_box_table_markdown(table))
+
+    def test_invalid_multiple_rows(self):
+        # A table with more than 2 rows
+        html = """
+        <table>
+            <tr><th>Header</th></tr>
+            <tr><td></td></tr>
+            <tr><td></td></tr>
+        </table>
+        """
+        soup = BeautifulSoup(html, "html.parser")
+        table = soup.find("table")
+        self.assertFalse(is_callout_box_table_markdown(table))
+
+    def test_invalid_non_empty_cell(self):
+        # A table with a non-empty cell
+        html = """
+        <table>
+            <tr><th>Header</th></tr>
+            <tr><td>Non-empty</td></tr>
+        </table>
+        """
+        soup = BeautifulSoup(html, "html.parser")
+        table = soup.find("table")
+        self.assertFalse(is_callout_box_table_markdown(table))
+
+    def test_invalid_no_cell(self):
+        # A table with no <td> cells
+        html = """
+        <table>
+            <tr><th>Header</th></tr>
+        </table>
+        """
+        soup = BeautifulSoup(html, "html.parser")
+        table = soup.find("table")
+        self.assertFalse(is_callout_box_table_markdown(table))
+
+    def test_invalid_no_rows(self):
+        # An empty table with no rows
+        html = "<table>Hello</table>"
+        soup = BeautifulSoup(html, "html.parser")
+        table = soup.find("table")
+        self.assertFalse(is_callout_box_table_markdown(table))
+
+
 class HTMLTableClassTests(TestCase):
     def _generate_table(self, num_cols, num_rows=1, cell="td", table_empty=False):
         rows = ""