# Test Organization - inspect_type
### Overview
This directory contains all functional tests for the `inspect_type` crate, organized by test purpose and functionality domain.
### Test File Organization
| `tests.rs` | Test suite entry point, imports all test modules |
| `inc/` | Internal test module with core functionality tests |
| `smoke_test.rs` | Smoke test placeholder; circular dep prevents test_tools use |
| `corner_cases_test.rs` | Comprehensive edge case and boundary condition testing across all type categories |
| `example_produces_output_test.rs` | Example quality verification ensuring examples demonstrate functionality |
### Test Categories
#### Core Functionality Tests (`inc/inspection.rs`)
- Basic macro invocation tests
- Output format verification
- Macro return value validation
- Demonstrates fundamental use cases (slices vs arrays)
#### Corner Cases Tests (`corner_cases_test.rs`)
Systematic testing across 16 categories:
1. **Primitive Types** - integers, floats, bool, char
2. **String Types** - String, &str, &String
3. **Collections - Arrays** - empty arrays, small arrays, large arrays, array references, slices
4. **Collections - Vec** - owned Vec, empty Vec, Vec references, slices from Vec
5. **Tuples** - unit tuple, 2-tuple, 3-tuple with mixed types
6. **Structs** - zero-sized, small, large with padding, struct references
7. **Enums** - unit enums, enums with data, Option, Result
8. **References and Pointers** - single/double/triple references, Box, Rc, Arc
9. **Generic Types** - Option with different types, Result
10. **Expression Testing** - literals, arithmetic expressions, method calls
11. **Macro Output Format** - format correctness, consistency between macros
12. **Edge Cases** - nested generics, zero-sized types
13. **Function Types and Closures** - function pointers (with/without params), non-capturing closures, capturing closures, closures with parameters
14. **Raw Pointers** - const raw pointers (*const T), mut raw pointers (*mut T)
15. **Trait Objects (DST)** - trait object references (&dyn Trait), boxed trait objects (Box<dyn Trait>)
16. **Type Alias Resolution** - type aliases resolve to underlying types
#### Example Quality Tests (`example_produces_output_test.rs`)
- Verifies examples compile and run successfully
- Ensures examples produce actual output (not empty)
- Validates output demonstrates core functionality
- Guards against broken or outdated examples
### Test Matrix
#### Test Coverage Goals
- ✅ Basic type inspection (primitives, references)
- ✅ Collection types (arrays, slices, Vec)
- ✅ Compound types (tuples, structs, enums)
- ✅ Smart pointers (Box, Rc, Arc)
- ✅ Generic types (Option, Result)
- ✅ Expression inspection
- ✅ Output format validation
- ✅ Macro consistency
- ✅ Example quality assurance
- ✅ Zero-sized types
- ✅ Nested generic types
- ✅ Reference layers (single, double, triple, quad)
- ✅ Function pointers and closures
- ✅ Raw pointers (*const T, *mut T)
- ✅ Trait objects (DST - dynamically sized types)
- ✅ Type alias resolution transparency
#### Known Limitations
- `smoke_test.rs` is empty — `test_tools` cannot be used due to circular dependency (`test_tools` depends on `inspect_type`)
### Running Tests
#### Run all tests
```bash
cargo test --all-features
```
#### Run specific test file
```bash
cargo test --test corner_cases_test
cargo test --test example_produces_output_test
```
#### Run with level 3 verification (clippy + doc tests)
```bash
w3 .test level::3
```
### Test Design Principles
1. **Real Over Mock** - All tests use real type inspection, no mocking
2. **Loud Failures** - Tests fail with clear, actionable error messages
3. **Environmental Independence** - Tests dont rely on external state
4. **One Aspect Per Test** - Each test validates single behavior
5. **Explicit Parameters** - No reliance on default values
### Manual Testing
No manual testing plan required - all functionality is automatable and covered by automated tests.
### Lessons Learned
#### Example Quality Verification
Creating `example_produces_output_test.rs` revealed that examples can become outdated during API transitions. Always verify examples actually demonstrate functionality, not just compile. This test prevents regression where examples become empty shells.
#### Corner Case Coverage
Systematic corner case testing across type categories ensures robust behavior. Organizing tests by type category (primitives, collections, compounds) makes it easy to verify comprehensive coverage and identify gaps.
#### Test File Size Management
The corner_cases_test.rs demonstrates good test organization: comprehensive coverage in single file under 500 lines, organized by clear categories with section headers. This approach balances discoverability with maintainability.