Adds validation for the examples

All examples must adhere to a strict format. We'll be adding a directory
with "unstructured" examples that don't adhere.

.github/workflows/python-package.yml

@@ -37,3 +37,16 @@ jobs:
       - name: Run tests
         run: |
           python -m pytest tests
+
+  validate-examples:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v3
+      - name: Install dependencies
+        run: |
+          python -m pip install -e ".[tests]"
+      - name: Validate examples
+        working-directory: ./examples
+        run: |
+          python -m pytest validate_examples.py

examples/blog_post/digraph_safe

@@ -0,0 +1,14 @@
+digraph {
+	graph [compound=false concentrate=false rankdir=TB ranksep=0.4]
+	human_input [label=human_input shape=box style=rounded]
+	input__prompt [label="input: prompt" shape=oval style=dashed]
+	input__prompt -> human_input
+	ai_response [label=ai_response shape=box style=rounded]
+	safety_check [label=safety_check shape=box style=rounded]
+	unsafe_response [label=unsafe_response shape=box style=rounded]
+	human_input -> safety_check [style=solid]
+	safety_check -> unsafe_response [label="safe=False" style=dashed]
+	safety_check -> ai_response [label="safe=True" style=dashed]
+	unsafe_response -> human_input [style=solid]
+	ai_response -> human_input [style=solid]
+}

examples/validate_examples.py

@@ -0,0 +1,43 @@
+import os
+
+EXAMPLES_DIR = "."
+REQUIRED_FILES = ["notebook.ipynb", "application.py", "README.md", "digraph.png"]
+
+FILTERLIST = []
+
+
+def should_validate(directory: str) -> bool:
+    """Return True if the given directory is an example directory."""
+    return (
+        os.path.isdir(os.path.join(EXAMPLES_DIR, directory))
+        and not directory.startswith(".")
+        and not directory.startswith("_")
+        and directory not in FILTERLIST
+    )
+
+
+def get_directories(base_path: str) -> list[str]:
+    """Return a list of directories under the given base_path."""
+    return [d for d in os.listdir(base_path) if should_validate(d)]
+
+
+def check_files_exist(directory, files):
+    """Check if each file in 'files' exists in 'directory'."""
+    missing_files = []
+    for file in files:
+        if not os.path.exists(os.path.join(EXAMPLES_DIR, directory, file)):
+            missing_files.append(file)
+    return missing_files
+
+
+# Use pytest_generate_tests to dynamically parameterize the fixture
+def pytest_generate_tests(metafunc):
+    # if "directory" in metafunc.fixturenames:
+    directories = get_directories(EXAMPLES_DIR)
+    metafunc.parametrize("directory", directories, scope="module")
+
+
+def test_directory_contents(directory):
+    required_files = ["notebook.ipynb", "application.py", "README.md", "digraph.png"]
+    missing_files = check_files_exist(directory, required_files)
+    assert not missing_files, f"Missing files in '{directory}': {', '.join(missing_files)}"