Positron Vitest Test Authoring

Write tests for Positron source code, then have them independently reviewed.

Arguments

$ARGUMENTS may contain:

• A file path (e.g., src/vs/.../myComponent.tsx) -- write tests for this specific file
• --branch <branch-name> to analyze all changes on a branch
• A PR number (e.g., #12242 or 12242) to analyze a pull request
• A PR URL (e.g., https://github.com/posit-dev/positron/pull/12242)

Phase 1: Branch/PR Analysis

Skip this phase if the argument is a specific source file path -- go directly to Phase 2 Prepare.

Run this phase when the argument is a branch name, PR number, or PR URL, or the user asks "what tests should I write?" without naming a file. Spawn an analysis subagent to produce a structured test plan -- this keeps the analysis work out of the main agent's context.