CodeCovPlug (name pending) is a WIP visual studio code extension that tries to grant the VSCode developer an easy answer to the following question:

What tests correspond to these line(s) of code?

Let us start with the following ideas

• Tests are essential for any codebase
• Tests provide a useful debugging tool
• Good tests implicitly describe what a piece of code should be doing
• Integration tests often need to be changed in response to rapidly evolving codebases
• Writing and running tests is an iterative process - a portion of a test suite may be run dozens of times over the course of a single feature ticket

One of the biggest complaints I hear around TDD is the time aspect. It takes time to write good tests, and it takes even longer to fix them. In large codebases touched by many hands, the problem of fixing tests worsens. Changing or refactoring a single existing feature may break dozens of tests that are scattered across the codebase, taking all the more time to fix.

The goal of this extension is to provide the tooling around test discovery and execution to make TDD as fun as possible.

So this extension is supposed to make identifying covered code easier. How is this done?

We start from a special kind of generated coverage file, such as the included contextcov.json. This file was generated from a simple script that parsed out coverage data from the python Coverage library with dynamic contexts enabled.

From here the idea is simple. The json file contains a mapping of file paths that correspond with line numbers, with each line number corresponding to a list of paths to tests. We have all the data we need.

PR's are welcome! The code is heavily based on the excellent git-lens project, particularly around the event driven system and hover logic. I recommend using that project as a reference for creating best-practice Vscode extensions in Typescript.

MVP

• Load a single coverage file into memory on extension startup or command execution (see contextcov.json)
• Display a hover popup on line mouseover that contains vscode hyperlinks to file:line paths

POST MVP Roadmap

• Display a hover popup that contains aggregated hyperlinks for a multi-line select
• Hover popup managed test execution
  • Vscode Configuration API for template based commands
  • "Run this test"
  • "Run all tests"
• Concatenate multiple coverage files
• Load coverage files from URL
• Load coverage files from S3
• [ ]

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