minitest-coder

# Minitest Coder

## Core Philosophy

- **AAA Pattern**: Arrange-Act-Assert structure for clarity
- **Behavior over Implementation**: Test what code does, not how
- **Isolation**: Tests should be independent
- **Descriptive Names**: Clear test descriptions
- **Coverage**: Test happy paths AND edge cases
- **Fast Tests**: Minimize database operations
- **Fixtures**: Use fixtures for test data

## Minitest Styles

| Style | Best For | Syntax |
|-------|----------|--------|
| Traditional | Simple unit tests | `test "description"` |
| Spec | Complex scenarios with contexts | `describe`/`it` with `let`/`subject` |

### Traditional Style

```ruby
class UserTest < ActiveSupport::TestCase
  test "validates presence of name" do
    user = User.new
    assert_not user.valid?
    assert_includes user.errors[:name], "can't be blank"
  end
end
```

### Spec Style

```ruby
class UserTest < ActiveSupport::TestCase
  describe "#full_name" do
    subject { user.full_name }
    let(:user) { User.new(first_name: "Buffy", last_name:) }

    describe "with last name" do
      let(:last_name) { "Summers" }

      it "returns full name" do
        assert_equal "Buffy Summers", subject
      end
    end
  end
end
```

## Test Organization

### File Structure

```
test/
├── models/           # Model unit tests
├── services/         # Service object tests
├── integration/      # Full-stack tests
├── mailers/          # Mailer tests
├── jobs/             # Background job tests
├── fixtures/         # Test data
└── test_helper.rb    # Configuration
```

### Naming Conventions

- Mirror app structure: `app/models/user.rb` → `test/models/user_test.rb`
- Use fully qualified namespace: `class Users::ProfileServiceTest`
- **Don't add** `require 'test_helper'` (auto-imported)

## Spec Style Patterns

See [resources/spec-patterns.md](resources/spec-patterns.md) for detailed examples.

| Pattern | Use Case |
|---------|----------|
| `subject { ... }` | Method under test |
| `let(:name) { ... }` | Lazy