How can I test and debug a custom tool before adding it to my workspace

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Development Environment Setup

Before testing your custom tool, ensure that your development environment is properly configured. This means having the right IDE, debuggers, SDKs, and deployment tools installed.

For instance, if you are developing a Google Workspace add-on, tools such as the Apps Script IDE, Node.js, Python environments, and Ngrok for tunneling are useful. Visual Studio Code is a widely recommended IDE for rich debugging features, while Visual Studio is necessary for debugging certain custom tools like T4 text templates or SingleFileGenerators.

Setting up your environment includes:
- Installing required runtimes and libraries (Node.js, Python, .NET, etc.).
- Configuring your IDE for debugging (launch.json in VS Code, or launch.vs.json in Visual Studio).
- Access to any APIs or services your tool interacts with.
- Acquiring necessary permissions for testing unpublished or developer tools in your environment.

For collaborative testing, ensure proper access management, such as sharing Projects and granting editor access.

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Local Testing of Unpublished Tools

Before publishing, test your custom tool in a controlled local or development environment. For example, Google Workspace add-ons can be installed as unpublished versions to test directly within supported host applications (Gmail, Docs, Sheets).

Steps to locally test include:
1. In the Apps Script editor, use the Deploy > Test deployments feature to install the unpublished add-on.
2. Refresh the host application to ensure the add-on appears.
3. Authorize the add-on if prompted.
4. Exercise the tool's features to verify behavior.

For Visual Studio custom tools or code generators, testing often means running the custom tool manually or setting the tool project as the startup project to debug it directly in the IDE.

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Debugging Techniques in IDEs

Debugging is critical to identify and fix issues during tool development. Most modern IDEs support breakpoints, inspecting variables, call stacks, and exception handling.

Visual Studio

For custom tools developed in Visual Studio (such as SingleFileGenerators or T4 templates):
- Attach the debugger to a running instance of Visual Studio (Tools > Attach to Process > devenv.exe).
- Alternatively, set Visual Studio itself as the startup project for your tool.
- Use breakpoints inside the code generation logic to trace execution.
- Launch custom build or debug configurations using launch.vs.json to control debugging sessions.
- Use detailed debugger windows such as Watch, Locals, and Call Stack to inspect runtime state.

For T4 text templates, rebuild the solution and start debugging to see the transformation steps and potential errors during template processing.

Visual Studio Code

VS Code supports creating debug configurations via a launch.json file:
- Generate initial configurations for Node.js, Python, or other languages.
- Add custom configurations for launch or attach debugging.
- Use breakpoints, variable watches, and an interactive debug console.
- Use extensions for language-specific debugging enhancements.
- With AI integrations like GitHub Copilot, you can generate debugging configurations faster.

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Remote and Local Environment Debugging

For tools deployed on remote servers or environments, debugging may require:
- Setting up SSH tunnels to forward debug ports from the remote machine to the local IDE.
- Using remote debugging configurations to attach the IDE debugger to the remote process.
- Employing tools like ngrok to create secure tunnels to localhost endpoints for real-time testing.

Example: Debugging Google Workspace add-ons that execute HTTP requests remotely can be done by enabling debugger ports, setting SSH tunnels, and attaching the local IDE debugger, then interacting with the add-on as if it were local.

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Automated Testing and Continuous Integration

To improve reliability, integrate automated tests for your custom tool:
- Write unit and integration tests for core logic.
- Use continuous integration (CI) systems to automatically run your tests on commits.
- Employ live unit testing features (e.g., Visual Studio's Live Unit Testing) to see test results as you code.
- Validate error handling, edge cases, and performance bottlenecks.

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Collaborating for Testing

When ready, share your custom tool with others for external testing:
- Provide editor access or share installation steps for unpublished add-ons.
- Gather feedback and bug reports systematically.
- Use version control branches to manage changes separate from main code.
- Document known issues and usage instructions clearly.

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Common Debugging Challenges and Solutions

- Authorization Issues: Tools like Google Workspace add-ons require OAuth scopes and permissions; missing or incorrect authorizations cause failures.
- Environment Differences: Behavior locally versus deployed environments may vary; use logging and consistent configurations.
- Tool Execution Errors: Debug by attaching to host processes or using verbose logging.
- Breakpoint Not Hit: Ensure debugging symbols are loaded and the correct process is attached.
- Performance Issues: Use profiling tools integrated within IDEs to identify bottlenecks.

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Summary

Testing and debugging a custom tool before adding it to a workspace involves preparing the development environment, running local tests and debugging sessions, leveraging IDE debug features, possibly debugging remotely, automating tests, and collaborating on feedback. Detailed setup and debugging techniques will vary based on the tool's platform and language but following structured procedures ensures robust and reliable tools before release.

For example, in Google Workspace:
- Use Apps Script IDE for deploying and testing unpublished add-ons.
- Employ Ngrok and SSH for debugging remote HTTP add-ons.
- Use Visual Studio Code or Visual Studio's debugging tools for breakpoints and inspecting code.

For Visual Studio custom tools:
- Attach debugger to Visual Studio processes.
- Use launch configuration files and custom build/debug tasks.
- Debug T4 templates by rebuilding within a debugging session.

Adhering to these best practices and workflows will help identify and fix issues effectively before your custom tool becomes part of the main workspace.

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