From 1c7917cb866b4d086426e98cfe5f62a4b144a217 Mon Sep 17 00:00:00 2001
From: Jake Howard <git@theorangeone.net>
Date: Fri, 1 Jul 2022 08:55:42 +0100
Subject: [PATCH] Add tests for ToC generator

---
 website/common/tests.py | 66 ++++++++++++++++++++++++++++++++++++++++-
 website/common/utils.py |  4 +++
 2 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/website/common/tests.py b/website/common/tests.py
index 660a769..d9d73fa 100644
--- a/website/common/tests.py
+++ b/website/common/tests.py
@@ -2,7 +2,7 @@ from django.test import SimpleTestCase
 
 from .embed import YouTubeLiteEmbedFinder
 from .models import BasePage
-from .utils import get_page_models
+from .utils import get_page_models, get_table_of_contents
 
 
 class BasePageTestCase(SimpleTestCase):
@@ -28,3 +28,67 @@ class YouTubeLiteEmbedFinderTestCase(SimpleTestCase):
         )
         with self.assertRaises(ValueError):
             YouTubeLiteEmbedFinder._get_video_id("something-else")
+
+
+class TableOfContentsTestCase(SimpleTestCase):
+    def test_creates_table_of_contents(self) -> None:
+        toc = get_table_of_contents(
+            """
+        <h2>2</h2>
+        <h3>2.1</h3>
+        <h3>2.2</h3>
+        <h4>2.2.1</h4>
+        <h3>2.3</h3>
+        <h2>3</h2>
+        <h3>3.1</h3>
+        <h2>4</h2>
+        """
+        )
+
+        self.assertEqual(len(toc), 3)
+        self.assertEqual([entry.title for entry in toc], ["2", "3", "4"])
+
+        first_entry = toc[0]
+        self.assertEqual(len(first_entry.children), 3)
+        self.assertEqual(
+            [entry.title for entry in first_entry.children], ["2.1", "2.2", "2.3"]
+        )
+
+        sub_entry = first_entry.children[1]
+        self.assertEqual(len(sub_entry.children), 1)
+        self.assertEqual([entry.title for entry in sub_entry.children], ["2.2.1"])
+
+        second_entry = toc[1]
+        self.assertEqual(len(second_entry.children), 1)
+        self.assertEqual([entry.title for entry in second_entry.children], ["3.1"])
+
+    def test_no_headings(self) -> None:
+        toc = get_table_of_contents("<p>I'm no heading</p>")
+        self.assertEqual(toc, [])
+
+    def test_no_content(self) -> None:
+        toc = get_table_of_contents("")
+        self.assertEqual(toc, [])
+
+    def test_non_sequential_headings(self) -> None:
+        toc = get_table_of_contents(
+            """
+        <h2>2</h2>
+        <h3>2.1</h3>
+        <h3>2.2</h3>
+        <h5>2.2.1</h5>
+        <h3>2.3</h3>
+        """
+        )
+
+        self.assertEqual(len(toc), 1)
+
+        first_entry = toc[0]
+        self.assertEqual(len(first_entry.children), 3)
+        self.assertEqual(
+            [entry.title for entry in first_entry.children], ["2.1", "2.2", "2.3"]
+        )
+
+        sub_entry = first_entry.children[1]
+        self.assertEqual(len(sub_entry.children), 1)
+        self.assertEqual([entry.title for entry in sub_entry.children], ["2.2.1"])
diff --git a/website/common/utils.py b/website/common/utils.py
index 1e19d24..1fefd08 100644
--- a/website/common/utils.py
+++ b/website/common/utils.py
@@ -26,6 +26,10 @@ def get_table_of_contents(html: str) -> list[TocEntry]:
         TocEntry(tag.text, tag.text, int(tag.name[1]), []) for tag in headings
     ]
 
+    # Abort if there are no headings
+    if not heading_levels:
+        return []
+
     # Ensure heading levels are sequential
     for heading, next_heading in pairwise(heading_levels):
         if next_heading.level - heading.level > 1: