fosmvvm-viewmodel-test-generator

# FOSMVVM ViewModel Test Generator

Generate test files for ViewModels following FOSMVVM testing patterns.

## Conceptual Foundation

> For full architecture context, see [FOSMVVMArchitecture.md](../../docs/FOSMVVMArchitecture.md#testing-support) | [OpenClaw reference]({baseDir}/references/FOSMVVMArchitecture.md)

ViewModel testing in FOSMVVM verifies three critical aspects:

1. **Codable round-trip** - ViewModel encodes and decodes without data loss
2. **Versioning stability** - Structure hasn't changed unexpectedly
3. **Multi-locale translations** - All `@LocalizedString` properties have values in all supported locales

The `LocalizableTestCase` protocol provides infrastructure that tests all three in a single call.

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## When to Use This Skill

- Creating tests for new ViewModels
- Adding test coverage to existing ViewModels
- Verifying localization completeness across locales
- Testing ViewModels with embedded/nested child ViewModels
- Verifying `@LocalizedSubs` substitution behavior

## What This Skill Generates

| File | Location | Purpose |
|------|----------|---------|
| `{Name}ViewModelTests.swift` | `Tests/{Target}Tests/Localization/` | Test suite conforming to `LocalizableTestCase` |
| `{Name}ViewModel.yml` | `Tests/{Target}Tests/TestYAML/` | YAML translations for test (if needed) |

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## The Testing Pattern

### Standard Pattern (Most Tests)

For most ViewModels, a single line provides complete coverage:

```swift
@Test func dashboardViewModel() throws {
    try expectFullViewModelTests(DashboardViewModel.self)
}
```

This verifies:
- Codable encoding/decoding
- Versioned ViewModel stability
- Translations exist for all locales (en, es by default)

**This is sufficient for the vast majority of ViewModel tests.**

### Extended Pattern (Specific Formatting Verification)

When testing specific formatting behavior (substitutions, compound strings), add locale-specific assertions:

```swift
@Test func greetingWithSubstitution() throws {
    try expectFu...