Skill v2.0.0
currentAutomated scan100/1002 files
name: backend-test description: Generate backend tests (unit, integration, mocks) for existing code. Auto-invoke when user says "write test for", "add test", "test this", or "create test". allowed-tools: Read, Write, Edit, Grep, Glob, Bash version: 2.0.0
Backend Test Generator
Generate backend tests for existing code — typically code that was written without tests, or where additional coverage is needed beyond what a code-writing skill (backend-endpoint) already produced.
When to use this vs. `backend-endpoint`:backend-endpointgenerates tests as part of creating a new endpoint. Usebackend-testwhen the code already exists and you need to add or expand its tests.
When to Invoke
Auto-invoke when user says:
- "Write test for [file/function]"
- "Add test" / "Add tests"
- "Test this"
- "Create test for [thing]"
- "Test the [api/service/function]"
Execution Steps
Step 0: Check Existing Patterns (Phase 0)
Query the knowledge graph for what we know about testing in this project:
PLUGIN_DIR="${CLAUDE_PLUGIN_ROOT:-$HOME/.claude/plugins/cache/navigator-marketplace/navigator}"[ -d "$PLUGIN_DIR" ] || PLUGIN_DIR="$HOME/.claude/plugins/marketplaces/navigator-marketplace"python3 "$PLUGIN_DIR/skills/nav-graph/functions/graph_manager.py" \--action query --concept testing \--graph-path .agent/knowledge/graph.json 2>/dev/null | head -40
Surface patterns (preferred frameworks, mocking conventions) and pitfalls (flaky-test gotchas). If the graph returns nothing, proceed without it.
Step 1: Locate Code Under Test
If the user named a specific file, use it. Otherwise, ask:
What should I test?- File path (e.g., src/services/userService.ts)- Function name (e.g., authenticateUser)- API endpoint (e.g., POST /api/login)
Read the target file in full so the generated tests cover its actual behavior, not assumed behavior.
Step 2: Detect Test Framework
# Jestgrep -q '"jest"' package.json 2>/dev/null && echo "Jest detected"# Vitestgrep -q '"vitest"' package.json 2>/dev/null && echo "Vitest detected"# Mochagrep -q '"mocha"' package.json 2>/dev/null && echo "Mocha detected"# Node test runner (built-in)[ -f "package.json" ] && grep -q '"test":\s*"node --test' package.json && echo "node:test detected"
Detect existing test patterns by reading a peer test file under __tests__/, tests/, or *.test.ts alongside the target.
Step 3: Generate Test File
File location: place tests where existing tests live (mirror the project's convention — colocated *.test.ts next to source, or under a tests/ directory).
Structure (Jest/Vitest):
import { describe, it, expect, beforeEach, vi } from 'vitest'; // or 'jest'import { {FUNCTION_NAME} } from '{TARGET_PATH}';describe('{FUNCTION_NAME}', () => {describe('happy path', () => {it('returns expected result for valid input', () => {const result = {FUNCTION_NAME}({VALID_INPUT});expect(result).toEqual({EXPECTED});});});describe('error cases', () => {it('throws on invalid input', () => {expect(() => {FUNCTION_NAME}({INVALID_INPUT})).toThrow();});});describe('edge cases', () => {it('handles empty input', () => { /* ... */ });it('handles boundary values', () => { /* ... */ });});});
For API/integration tests (supertest pattern):
import request from 'supertest';import { app } from '{APP_PATH}';describe('{METHOD} {PATH}', () => {it('returns 200 for valid request', async () => {const response = await request(app).{method}('{PATH}').send({BODY});expect(response.status).toBe(200);expect(response.body).toMatchObject({EXPECTED_SHAPE});});it('returns 4xx for invalid request', async () => {const response = await request(app).{method}('{PATH}').send({BAD_BODY});expect(response.status).toBe(400);});});
Step 4: Verify
Run the generated tests:
{TEST_COMMAND} {TEST_FILE_PATH}
If any fail because tests assume incorrect behavior, fix the tests, not the source — unless the source has an actual bug. If the source is buggy, surface that to the user; don't silently change it.
Step 5: Emit Execution Summary (Graph Ingestion)
{"execution_summary": {"skill": "backend-test","task": "tests for {TARGET}","files_created": ["{test file path}"],"files_modified": [],"tests_added": ["{test file path}"],"stack_detected": "{e.g. vitest+supertest}","patterns_followed": [{"summary": "{e.g. supertest pattern for HTTP integration tests}", "concepts": ["testing", "api"], "confidence": 0.8}],"decisions_made": [{"summary": "{e.g. mocked the DB client because tests must run offline}", "concepts": ["testing"], "confidence": 0.75}],"pitfalls_avoided": [],"assumptions_made": ["{e.g. project uses Vitest globals — no explicit import needed}"]}}
Ingest:
PLUGIN_DIR="${CLAUDE_PLUGIN_ROOT:-$HOME/.claude/plugins/cache/navigator-marketplace/navigator}"[ -d "$PLUGIN_DIR" ] || PLUGIN_DIR="$HOME/.claude/plugins/marketplaces/navigator-marketplace"echo '<execution_summary JSON>' | python3 "$PLUGIN_DIR/skills/nav-graph/functions/execution_to_graph.py" -
Success Criteria
- [ ] Test file located where the project keeps tests (mirrors convention)
- [ ] Happy path, error cases, and at least one edge case covered
- [ ] Mocks isolate the unit under test
- [ ] All generated tests pass on first run (or surface real bugs in the source)
- [ ] Execution summary emitted
When NOT to Use This Skill
- You're creating a new endpoint from scratch — use
backend-endpoint(it generates tests as part of its workflow) - You want to test a UI component — use
frontend-test