Add test to verify tutorial table of contents

.github/workflows/ci_test.yml

@@ -106,3 +106,15 @@ jobs:
       - run: pip install pygithub click
       - name: Check that the CODEOWNERS is valid
         run: python .github/workflows/notify_codeowners.py .github/CODEOWNERS
+  tutorial-table-of-contents:
+    name: Check that all tutorials are included in documentation
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v1
+        with:
+          python-version: 3.7
+      - run: pip install pyyaml
+      - name: Check that all tutorials are included in table of contents
+        run: python .github/workflows/verify_tutorial_toc.py
+

.github/workflows/verify_tutorial_toc.py

@@ -0,0 +1,46 @@
+import yaml
+from pathlib import Path
+
+
+def get_yaml_links():
+    with open("docs/tutorials/_toc.yaml", "r") as stream:
+        toc = yaml.safe_load(stream)["toc"]
+
+    links = [x["path"].split("/")[-1] for x in toc if "path" in x]
+    links.remove("overview")
+
+    links_set = set(links)
+    assert len(links) == len(
+        links_set
+    ), "There are duplicate links in the table of contents"
+
+    return links_set
+
+
+def get_tutorial_notebooks():
+    tutorial_dir = Path("docs/tutorials")
+    notebooks = [x.stem for x in tutorial_dir.glob("*.ipynb")]
+    notebooks.remove("_template")
+
+    notebook_set = set(notebooks)
+
+    assert len(notebooks) == len(notebook_set), "There are duplicate notebook filenames"
+
+    return notebook_set
+
+
+def verify_table_of_contents():
+
+    links = get_yaml_links()
+    tutorials = get_tutorial_notebooks()
+    difference = links ^ tutorials
+
+    assert (
+        len(difference) == 0
+    ), "{0} tutorials were not found as ipython notebooks and table of contents links".format(
+        difference
+    )
+
+
+if __name__ == "__main__":
+    verify_table_of_contents()

docs/tutorials/_toc.yaml

@@ -18,3 +18,7 @@ toc:
   path: /addons/tutorials/tqdm_progress_bar
 - title: Seq2Seq for Translation
   path: /addons/tutorials/networks_seq2seq_nmt
+- title: Moving Average Optimizer Checkpoint
+  path: /addons/tutorials/average_optimizers_callback
+- title: Time Stopping Callback
+  path: /addons/tutorials/time_stopping