Cursor rule

1---
2description: 'Middle Earth testing baseline guidelines (unit tests with Jest)'
3globs:
4  - '**/*.spec.ts'
5  - '**/*.spec.tsx'
6  - '**/*.test.ts'
7  - '**/*.test.tsx'
8alwaysApply: false
9---
10 
11# Testing (Middle Earth)
12 
13## Unit tests (Jest)
14 
15- Tests live in `__tests__/` folders within the same directory as source files.
16- Filename pattern: `*.spec.ts(x)`.
17- Use framework-specific testing libraries (e.g., Testing Library for React).
18- Use shared testing helpers when available; keep tests short and behavior-focused.
19- Aim for 100% coverage where feasible; write tests that target behavior, not implementation details.
20 
21## Fixtures and data
22 
23- Use `faker` for generating random inputs where helpful.
24- Prefer deterministic assertions over random expected values.
25 
26## Mocking
27 
28- Prefer `jest.mock` for external modules and `jest.spyOn` for side effects.
29- Use table-driven tests with `it.each` for input/output matrices.
30 
31## Assertions
32 
33- Prefer `expect.objectContaining`/`not.objectContaining` for partial assertions.
34- Disallow `.only` (lint rule enabled) and skipped tests except when justified.
35 
36## Running tests
37 
38```bash
39# Test a specific project
40pnpm nx test <project-name>
41 
42# Test all projects
43pnpm nx run-many --target test
44```
45