testing-strategies

name	testing-strategies
description	Build confidence with comprehensive CLI testing. Unit tests catch logic bugs with fakes, integration tests verify API contracts, E2E tests validate workflows.

Testing Strategies

When to Use This Skill

A well-tested CLI uses different testing strategies at different levels. This section covers:

• Unit Testing - Fake clients and interface-based design
• Integration Testing - envtest and real API servers
• E2E Testing - Full workflow tests in CI/CD

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Implementation

See the full implementation guide in the source documentation.

Key Principles

Practice	Description
Interface first	Design for testability with interfaces
Table-driven tests	Cover edge cases systematically
Parallel tests	Use t.Parallel() where safe
Build tags	Separate integration tests with //go:build integration
Clean up	Always clean up test resources

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Test at the right level. Unit tests catch logic bugs. Integration tests catch API issues. E2E tests catch workflow bugs.

Techniques

Overview

A well-tested CLI uses different testing strategies at different levels. This section covers:

• Unit Testing - Fake clients and interface-based design
• Integration Testing - envtest and real API servers
• E2E Testing - Full workflow tests in CI/CD

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Testing Pyramid

graph TB
    E2E[E2E Tests<br/>Full workflow in real cluster]
    Integration[Integration Tests<br/>Real API server with kind/envtest]
    Unit[Unit Tests<br/>Fake clients and mock interfaces]

    E2E --> Integration --> Unit

    %% Ghostty Hardcore Theme
    style E2E fill:#9e6ffe,color:#1b1d1e
    style Integration fill:#65d9ef,color:#1b1d1e
    style Unit fill:#a7e22e,color:#1b1d1e

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Test Organization

myctl/
├── cmd/
│   ├── check.go
│   └── check_test.go        # Command tests
├── pkg/
│   ├── k8s/
│   │   ├── client.go
│   │   ├── client_test.go   # Unit tests with fakes
│   │   └── fake_client.go   # Test doubles
│   └── selector/
│       ├── selector.go
│       └── selector_test.go
└── test/
    ├── e2e/                  # E2E tests
    └── fixtures/             # Test resources

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Makefile Targets

.PHONY: test test-unit test-integration test-e2e

test: test-unit

test-unit:
    go test -v -race ./...

test-integration:
    go test -v -tags=integration ./pkg/...

test-e2e:
    ./test/e2e/run.sh

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Best Practices

Practice	Description
Interface first	Design for testability with interfaces
Table-driven tests	Cover edge cases systematically
Parallel tests	Use t.Parallel() where safe
Build tags	Separate integration tests with //go:build integration
Clean up	Always clean up test resources

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Test at the right level. Unit tests catch logic bugs. Integration tests catch API issues. E2E tests catch workflow bugs.

Examples

See examples.md for code examples.

References

• Source Documentation
• AEL Build