Add: Comprehensive Docker environment tests and documentation

.dockerignore

@@ -0,0 +1,42 @@
+# Version control
+.git
+.gitignore
+
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+env/
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+.hypothesis/
+.pytest_cache/
+
+# VS Code
+.vscode/
+*.code-workspace

Dockerfile.test

@@ -0,0 +1,17 @@
+# Use the official Python image as base
+FROM python:3.11-slim
+
+# Set working directory
+WORKDIR /app
+
+# Copy requirements first for better caching
+COPY requirements.txt .
+
+# Install dependencies
+RUN pip install -r requirements.txt
+
+# Copy the rest of the application
+COPY . .
+
+# Run tests by default
+CMD ["pytest", "-v", "--cov=app", "tests/"]

README.md

@@ -1,23 +1,132 @@
 # Try Out Development Containers: Python
 
 [![Open in Dev Containers](https://img.shields.io/static/v1?label=Dev%20Containers&message=Open&color=blue&logo=visualstudiocode)](https://vscode.dev/redirect?url=vscode://ms-vscode-remote.remote-containers/cloneInVolume?url=https://github.com/microsoft/vscode-remote-try-python)
+[![Tests](https://github.com/microsoft/vscode-remote-try-python/actions/workflows/tests.yml/badge.svg)](https://github.com/microsoft/vscode-remote-try-python/actions/workflows/tests.yml)
 
 A **development container** is a running container with a well-defined tool/runtime stack and its prerequisites. You can try out development containers with **[GitHub Codespaces](https://github.com/features/codespaces)** or **[Visual Studio Code Dev Containers](https://aka.ms/vscode-remote/containers)**.
 
-This is a sample project that lets you try out either option in a few easy steps. We have a variety of other [vscode-remote-try-*](https://github.com/search?q=org%3Amicrosoft+vscode-remote-try-&type=Repositories) sample projects, too.
+This is a sample project that lets you try out either option in a few easy steps. We have a variety of other [vscode-remote-try-\*](https://github.com/search?q=org%3Amicrosoft+vscode-remote-try-&type=Repositories) sample projects, too.
 
-> **Note:** If you already have a codespace or dev container, you can jump to the [Things to try](#things-to-try) section. 
+## Testing
+
+This project includes comprehensive automated tests that verify both the Flask application functionality and Docker environment configuration.
+
+### Testing Components
+
+The test suite consists of two main parts:
+
+1. **Application Tests** (`tests/test_app.py`)
+
+   - Validates Flask routes and responses
+   - Checks static file serving
+   - Verifies content types and status codes
+
+2. **Docker Environment Tests** (`tests/test_docker_environment.py`)
+   - Verifies Python version and dependencies
+   - Checks container configuration
+   - Tests environment variables and paths
+   - Validates port availability and networking
+
+### Running Tests in Docker (Recommended)
+
+The most reliable way to run tests is using Docker, which ensures a consistent environment:
+
+```bash
+# Build the test image
+docker build -t vscode-remote-test -f Dockerfile.test .
+
+# Run tests with coverage report
+docker run vscode-remote-test
+
+# Run specific test file
+docker run vscode-remote-test pytest -v tests/test_docker_environment.py
+
+# Run tests with detailed output
+docker run vscode-remote-test pytest -v --log-cli-level=INFO tests/
+```
+
+### Running Tests Locally
+
+Before running tests locally, set up a Python virtual environment:
+
+```bash
+# Create and activate virtual environment
+python -m venv .venv
+source .venv/bin/activate  # On Windows: .venv\Scripts\activate
+
+# Install dependencies
+pip install -r requirements.txt
+
+# Run all tests
+python -m pytest -v tests/
+
+# Run tests with coverage report
+python -m pytest --cov=app --cov-report=html tests/
+
+# Run specific test file
+python -m pytest -v tests/test_app.py
+
+# Run tests in watch mode (auto-rerun on file changes)
+python -m pytest -f -v tests/
+```
+
+### Test Coverage
+
+The test suite verifies:
+
+- Index route returns correct status code and content type
+- Static files are served correctly
+- Docker container environment configuration
+- HTML content matches expectations
+
+> **Note:** If you already have a codespace or dev container, you can jump to the [Things to try](#things-to-try) section.
 
 ## Setting up the development container
 
 ### GitHub Codespaces
+
 Follow these steps to open this sample in a Codespace:
+
 1. Click the **Code** drop-down menu.
 2. Click on the **Codespaces** tab.
 3. Click **Create codespace on main** .
 
 For more information on creating your codespace, visit the [GitHub documentation](https://docs.github.com/en/free-pro-team@latest/github/developing-online-with-codespaces/creating-a-codespace#creating-a-codespace).
 
+## Testing
+
+This project includes automated tests that can be run both locally and in the container.
+
+### Running Tests in Container
+
+```bash
+# Install dependencies
+pip install -r requirements.txt
+
+# Run tests
+python -m pytest tests/
+
+# Run tests with coverage report
+python -m pytest --cov=app tests/
+```
+
+### Test Coverage
+
+The test suite verifies:
+
+- Index route returns correct status code and content type
+- Static files are served correctly
+- Docker container environment configuration
+- HTML content matches expectations
+
+### Running Tests in Development
+
+When developing new features, you can use the following command to run tests in watch mode:
+
+```bash
+python -m pytest -v tests/
+```
+
 ### VS Code Dev Containers
 
 If you already have VS Code and Docker installed, you can click the badge above or [here](https://vscode.dev/redirect?url=vscode://ms-vscode-remote.remote-containers/cloneInVolume?url=https://github.com/microsoft/vscode-remote-try-python) to get started. Clicking these links will cause VS Code to automatically install the Dev Containers extension if needed, clone the source code into a container volume, and spin up a dev container for use.
@@ -28,9 +137,9 @@ Follow these steps to open this sample in a container using the VS Code Dev Cont
 
 2. To use this repository, you can either open the repository in an isolated Docker volume:
 
-    - Press <kbd>F1</kbd> and select the **Dev Containers: Try a Sample...** command.
-    - Choose the "Python" sample, wait for the container to start, and try things out!
-        > **Note:** Under the hood, this will use the **Dev Containers: Clone Repository in Container Volume...** command to clone the source code in a Docker volume instead of the local filesystem. [Volumes](https://docs.docker.com/storage/volumes/) are the preferred mechanism for persisting container data.   
+   - Press <kbd>F1</kbd> and select the **Dev Containers: Try a Sample...** command.
+   - Choose the "Python" sample, wait for the container to start, and try things out!
+     > **Note:** Under the hood, this will use the **Dev Containers: Clone Repository in Container Volume...** command to clone the source code in a Docker volume instead of the local filesystem. [Volumes](https://docs.docker.com/storage/volumes/) are the preferred mechanism for persisting container data.
 
    Or open a locally cloned copy of the code:
 
@@ -45,46 +154,48 @@ Once you have this sample opened, you'll be able to work with it like you would
 Some things to try:
 
 1. **Edit:**
+
    - Open `app.py`
    - Try adding some code and check out the language features.
    - Make a spelling mistake and notice it is detected. The [Code Spell Checker](https://marketplace.visualstudio.com/items?itemName=streetsidesoftware.code-spell-checker) extension was automatically installed because it is referenced in `.devcontainer/devcontainer.json`.
    - Also notice that utilities like `pylint` and the [Python](https://marketplace.visualstudio.com/items?itemName=ms-python.python) extension are installed. Tools are installed in the `mcr.microsoft.com/devcontainers/python` image and Dev Container settings and metadata are automatically picked up from [image labels](https://containers.dev/implementors/reference/#labels).
 
+2. **Terminal:**
 
-2. **Terminal:** 
-    - Press <kbd>ctrl</kbd>+<kbd>shift</kbd>+<kbd>\`</kbd> to open a terminal window.
-    - Type `python -m flask run --port 9000 --no-debugger --no-reload` to run the app.
-         - The terminal will say your app is `Running on http://127.0.0.1:9000/`. Click on the link in the terminal to view your app running in the browser.
-    - Notice that the Python extension is already installed in the container since the `.devcontainer/devcontainer.json` lists `"ms-python.python"` as an extension to install automatically when the container is created.
-
-      > **Tip:** If you use this container outside of VS Code via `docker run` with `-p 9000`, you may need to append `--host 0.0.0.0` to the command above. The `-p` option "publishes" the port rather than forwarding it. It therefore will not work if the application only listens to localhost. The `forwardPorts` property in `devcontainer.json` does not have this limitation, but you can use `appPort` property instead if you want to mirror the `docker run` behavior.
+   - Press <kbd>ctrl</kbd>+<kbd>shift</kbd>+<kbd>\`</kbd> to open a terminal window.
+   - Type `python -m flask run --port 9000 --no-debugger --no-reload` to run the app.
+     - The terminal will say your app is `Running on http://127.0.0.1:9000/`. Click on the link in the terminal to view your app running in the browser.
+   - Notice that the Python extension is already installed in the container since the `.devcontainer/devcontainer.json` lists `"ms-python.python"` as an extension to install automatically when the container is created.
+
+     > **Tip:** If you use this container outside of VS Code via `docker run` with `-p 9000`, you may need to append `--host 0.0.0.0` to the command above. The `-p` option "publishes" the port rather than forwarding it. It therefore will not work if the application only listens to localhost. The `forwardPorts` property in `devcontainer.json` does not have this limitation, but you can use `appPort` property instead if you want to mirror the `docker run` behavior.
 
 3. **Build, Run, and Debug:**
+
    - Open `app.py`
    - Add a breakpoint (e.g. on line 9).
    - Press <kbd>F5</kbd> to launch the app in the container.
    - Once the breakpoint is hit, try hovering over variables (e.g. the app variable on line 7), examining locals, and more.
-   - Continue (<kbd>F5</kbd>). You can connect to the server in the container by either: 
-      - Clicking on `Open in Browser` in the notification telling you: `Your service running on port 9000 is available`.
-      - Clicking the globe icon in the 'Ports' view. The 'Ports' view gives you an organized table of your forwarded ports, and you can access it with the command **Ports: Focus on Ports View**.
+   - Continue (<kbd>F5</kbd>). You can connect to the server in the container by either:
+     - Clicking on `Open in Browser` in the notification telling you: `Your service running on port 9000 is available`.
+     - Clicking the globe icon in the 'Ports' view. The 'Ports' view gives you an organized table of your forwarded ports, and you can access it with the command **Ports: Focus on Ports View**.
    - Notice port 9000 in the 'Ports' view is labeled "Hello Remote World." In `devcontainer.json`, you can set `"portsAttributes"`, such as a label for your forwarded ports and the action to be taken when the port is autoforwarded.
-   
+
    > **Note:** In Dev Containers, you can access your app at `http://localhost:9000` in a local browser. But in a browser-based Codespace, you must click the link from the notification or the `Ports` view so that the service handles port forwarding in the browser and generates the correct URL.
 
 4. **Rebuild or update your container**
 
-   You may want to make changes to your container, such as installing a different version of a software or forwarding a new port. You'll rebuild your container for your changes to take effect. 
+   You may want to make changes to your container, such as installing a different version of a software or forwarding a new port. You'll rebuild your container for your changes to take effect.
 
    **Open browser automatically:** As an example change, let's update the `portsAttributes` in the `.devcontainer/devcontainer.json` file to open a browser when our port is automatically forwarded.
-   
+
    - Open the `.devcontainer/devcontainer.json` file.
    - Modify the `"onAutoForward"` attribute in your `portsAttributes` from `"notify"` to `"openBrowser"`.
-   - Press <kbd>F1</kbd> and select the **Dev Containers: Rebuild Container** or **Codespaces: Rebuild Container** command so the modifications are picked up.  
+   - Press <kbd>F1</kbd> and select the **Dev Containers: Rebuild Container** or **Codespaces: Rebuild Container** command so the modifications are picked up.
 
 5. **Install Node.js using a Dev Container Feature:**
    - Press <kbd>F1</kbd> and select the **Dev Containers: Configure Container Features...** or **Codespaces: Configure Container Features...** command.
    - Type "node" in the text box at the top.
-   - Check the check box next to "Node.js (via nvm) and yarn" (published by devcontainers) 
+   - Check the check box next to "Node.js (via nvm) and yarn" (published by devcontainers)
    - Click OK
    - Press <kbd>F1</kbd> and select the **Dev Containers: Rebuild Container** or **Codespaces: Rebuild Container** command so the modifications are picked up.
 
@@ -94,7 +205,7 @@ Some things to try:
 
 ## Contributing
 
-This project welcomes contributions and suggestions.  Most contributions require you to agree to a
+This project welcomes contributions and suggestions. Most contributions require you to agree to a
 Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us
 the rights to use your contribution. For details, visit https://cla.microsoft.com.
 

SECURITY.md

@@ -12,19 +12,19 @@ If you believe you have found a security vulnerability in any Microsoft-owned re
 
 Instead, please report them to the Microsoft Security Response Center (MSRC) at [https://msrc.microsoft.com/create-report](https://aka.ms/opensource/security/create-report).
 
-If you prefer to submit without logging in, send email to [secure@microsoft.com](mailto:secure@microsoft.com).  If possible, encrypt your message with our PGP key; please download it from the [Microsoft Security Response Center PGP Key page](https://aka.ms/opensource/security/pgpkey).
+If you prefer to submit without logging in, send email to [secure@microsoft.com](mailto:secure@microsoft.com). If possible, encrypt your message with our PGP key; please download it from the [Microsoft Security Response Center PGP Key page](https://aka.ms/opensource/security/pgpkey).
 
-You should receive a response within 24 hours. If for some reason you do not, please follow up via email to ensure we received your original message. Additional information can be found at [microsoft.com/msrc](https://aka.ms/opensource/security/msrc). 
+You should receive a response within 24 hours. If for some reason you do not, please follow up via email to ensure we received your original message. Additional information can be found at [microsoft.com/msrc](https://aka.ms/opensource/security/msrc).
 
 Please include the requested information listed below (as much as you can provide) to help us better understand the nature and scope of the possible issue:
 
-  * Type of issue (e.g. buffer overflow, SQL injection, cross-site scripting, etc.)
-  * Full paths of source file(s) related to the manifestation of the issue
-  * The location of the affected source code (tag/branch/commit or direct URL)
-  * Any special configuration required to reproduce the issue
-  * Step-by-step instructions to reproduce the issue
-  * Proof-of-concept or exploit code (if possible)
-  * Impact of the issue, including how an attacker might exploit the issue
+- Type of issue (e.g. buffer overflow, SQL injection, cross-site scripting, etc.)
+- Full paths of source file(s) related to the manifestation of the issue
+- The location of the affected source code (tag/branch/commit or direct URL)
+- Any special configuration required to reproduce the issue
+- Step-by-step instructions to reproduce the issue
+- Proof-of-concept or exploit code (if possible)
+- Impact of the issue, including how an attacker might exploit the issue
 
 This information will help us triage your report more quickly.
 

app.py

@@ -3,9 +3,16 @@
 # Licensed under the MIT License. See LICENSE in the project root for license information.
 #-----------------------------------------------------------------------------------------
 
+# Import the Flask web framework
 from flask import Flask
+
+# Create a new Flask web application instance
 app = Flask(__name__)
 
+# Define a route for the root URL "/"
+# When someone visits the homepage, this function will be called
 @app.route("/")
 def hello():
-    return app.send_static_file("index.html")
+    # Return the contents of index.html from the static folder
+    # Flask automatically looks for static files in the 'static' directory
+    return app.send_static_file("index.html")

requirements.txt

@@ -1 +1,3 @@
-flask
+flask
+pytest==7.4.0
+pytest-cov==4.1.

tests/conftest.py

@@ -0,0 +1,6 @@
+"""Configure pytest for the project."""
+import os
+import sys
+
+# Add the root directory to Python path
+sys.path.insert(0, os.path.abspath(os.path.dirname(os.path.dirname(__file__))))