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1---
2description: Writing and organizing tests
3globs: 
4alwaysApply: false
5---
6# Module Testing Pattern
7 
8## Overview
9 
10This codebase follows a specific pattern for organizing tests: tests for a module should be placed inside a subdirectory of that module called `tests`.
11 
12## Why This Pattern?
13 
14- **Colocation**: Tests are located near the code they test, making them easier to find and maintain
15- **Isolation**: Tests are separated from implementation code while still being part of the module
16- **Organization**: Multiple test files can be organized within the tests directory
17- **Module-specific tests**: Tests that are specific to a module's implementation details stay with that module
18 
19## Implementation
20 
21For a module `foo`, structure the tests as follows:
22 
23```
24src/foo/
25├── mod.rs           # Main module file
26├── component1.rs    # Module component
27├── component2.rs    # Module component
28└── tests/           # Tests directory
29    ├── mod.rs       # Test module declaration
30    ├── component1_tests.rs  # Tests for component1
31    └── component2_tests.rs  # Tests for component2
32```
33 
34In the main module's `mod.rs`, include the tests module conditionally:
35 
36```rust
37// ... module code ...
38 
39// Include tests module when running tests but not in normal builds
40#[cfg(test)]
41pub mod tests;
42 
43// ... rest of module code ...
44```
45 
46## Example
47 
48The `snapshot` module demonstrates this pattern:
49 
50- `src/snapshot/mod.rs` includes the tests module conditionally
51- `src/snapshot/tests/` contains test files for components and resources
52- Test files use the same imports and naming conventions as the implementation code
53 
54## Usage
55 
56When adding new functionality to a module:
571. Create corresponding test(s) in the module's `tests/` directory
582. Name test files with a `_tests` suffix (e.g., `component_tests.rs`)
593. Ensure all public API components are tested
604. Use descriptive test names that explain what's being tested