polyglot-test-agent

SKILL.md

Polyglot Test Generation Skill

An AI-powered skill that generates comprehensive, workable unit tests for any programming language using a coordinated multi-agent pipeline.

When to Use This Skill

Use this skill when you need to:

Generate unit tests for an entire project or specific files

Improve test coverage for existing codebases

Create test files that follow project conventions

Write tests that actually compile and pass

Add tests for new features or untested code

How It Works

This skill coordinates multiple specialized agents in a Research → Plan → Implement pipeline:

Pipeline Overview
┌─────────────────────────────────────────────────────────────┐
│                     TEST GENERATOR                          │
│  Coordinates the full pipeline and manages state            │
└─────────────────────┬───────────────────────────────────────┘
                      │
        ┌─────────────┼─────────────┐
        ▼             ▼             ▼
┌───────────┐  ┌───────────┐  ┌───────────────┐
│ RESEARCHER│  │  PLANNER  │  │  IMPLEMENTER  │
│           │  │           │  │               │
│ Analyzes  │  │ Creates   │  │ Writes tests  │
│ codebase  │→ │ phased    │→ │ per phase     │
│           │  │ plan      │  │               │
└───────────┘  └───────────┘  └───────┬───────┘
                                      │
                    ┌─────────┬───────┼───────────┐
                    ▼         ▼       ▼           ▼
              ┌─────────┐ ┌───────┐ ┌───────┐ ┌───────┐
              │ BUILDER │ │TESTER │ │ FIXER │ │LINTER │
              │         │ │       │ │       │ │       │
              │ Compiles│ │ Runs  │ │ Fixes │ │Formats│
              │ code    │ │ tests │ │ errors│ │ code  │
              └─────────┘ └───────┘ └───────┘ └───────┘

Step-by-Step Instructions

Step 1: Determine the User Request

Make sure you understand what user is asking and for what scope.
When the user does not express strong requirements for test style, coverage goals, or conventions, source the guidelines from unit-test-generation.prompt.md. This prompt provides best practices for discovering conventions, parameterization strategies, coverage goals (aim for 80%), and language-specific patterns.

Step 2: Invoke the Test Generator

Start by calling the polyglot-test-generator agent with your test generation request:

Generate unit tests for [path or description of what to test], following the [unit-test-generation.prompt.md](unit-test-generation.prompt.md) guidelines

The Test Generator will manage the entire pipeline automatically.

Step 3: Research Phase (Automatic)

The polyglot-test-researcher agent analyzes your codebase to understand:

Language & Framework: Detects C#, TypeScript, Python, Go, Rust, Java, etc.

Testing Framework: Identifies MSTest, xUnit, Jest, pytest, go test, etc.

Project Structure: Maps source files, existing tests, and dependencies

Build Commands: Discovers how to build and test the project

Output: .testagent/research.md

Step 4: Planning Phase (Automatic)

The polyglot-test-planner agent creates a structured implementation plan:

Groups files into logical phases (2-5 phases typical)

Prioritizes by complexity and dependencies

Specifies test cases for each file

Defines success criteria per phase

Output: .testagent/plan.md

Step 5: Implementation Phase (Automatic)

The polyglot-test-implementer agent executes each phase sequentially:

Read source files to understand the API

Write test files following project patterns

Build using the polyglot-test-builder subagent to verify compilation

Test using the polyglot-test-tester subagent to verify tests pass

Fix using the polyglot-test-fixer subagent if errors occur

Lint using the polyglot-test-linter subagent for code formatting

Each phase completes before the next begins, ensuring incremental progress.

Coverage Types

Happy path: Valid inputs produce expected outputs

Edge cases: Empty values, boundaries, special characters

Error cases: Invalid inputs, null handling, exceptions

State Management

All pipeline state is stored in .testagent/ folder:

File
Purpose

.testagent/research.md
Codebase analysis results

.testagent/plan.md
Phased implementation plan

.testagent/status.md
Progress tracking (optional)

Examples

Example 1: Full Project Testing

Generate unit tests for my Calculator project at C:\src\Calculator

Example 2: Specific File Testing

Generate unit tests for src/services/UserService.ts

Example 3: Targeted Coverage

Add tests for the authentication module with focus on edge cases

Agent Reference

Agent
Purpose
Tools

polyglot-test-generator
Coordinates pipeline
runCommands, codebase, editFiles, search, runSubagent

polyglot-test-researcher
Analyzes codebase
runCommands, codebase, editFiles, search, fetch, runSubagent

polyglot-test-planner
Creates test plan
codebase, editFiles, search, runSubagent

polyglot-test-implementer
Writes test files
runCommands, codebase, editFiles, search, runSubagent

polyglot-test-builder
Compiles code
runCommands, codebase, search

polyglot-test-tester
Runs tests
runCommands, codebase, search

polyglot-test-fixer
Fixes errors
runCommands, codebase, editFiles, search

polyglot-test-linter
Formats code
runCommands, codebase, search

Requirements

Project must have a build/test system configured

Testing framework should be installed (or installable)

VS Code with GitHub Copilot extension

Troubleshooting

Tests don't compile

The polyglot-test-fixer agent will attempt to resolve compilation errors. Check .testagent/plan.md for the expected test structure.

Tests fail

Review the test output and adjust test expectations. Some tests may require mocking dependencies.

Wrong testing framework detected

Specify your preferred framework in the initial request: "Generate Jest tests for..."