Contract Test Design

Contract Test Design

When to Use This Skill

Use this skill when:

• Contract Test Design tasks - Working on consumer-driven contract testing strategies using Pact
• Planning or design - Need guidance on contract testing approaches
• Best practices - Want to follow established patterns and standards

Overview

Contract testing verifies that services communicate correctly by testing the contract (API agreement) between a consumer and provider. Consumer-driven contracts (CDC) ensure providers don't break their consumers.

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Contract Testing vs Other Test Types

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Consumer-Driven Contract Flow

┌─────────────────────────────────────────────────────────────┐
│                    CONSUMER SIDE                            │
│                                                             │
│  1. Consumer writes test   2. Test generates contract       │
│     ┌──────────────┐          ┌──────────────┐              │
│     │ Consumer     │          │   Contract   │              │
│     │ Test         │  ─────►  │   (JSON)     │              │
│     └──────────────┘          └──────────────┘              │
│                                      │                      │
└──────────────────────────────────────┼──────────────────────┘
                                       │
                                       ▼ Publish to Broker
                              ┌──────────────────┐
                              │  Contract Broker │
                              │  (Pact Broker)   │
                              └────────┬─────────┘
                                       │
┌──────────────────────────────────────┼──────────────────────┐
│                    PROVIDER SIDE     │                      │
│                                      ▼                      │
│  3. Provider verifies contract                              │
│     ┌──────────────┐          ┌──────────────┐              │
│     │  Provider    │  ◄─────  │   Contract   │              │
│     │  Verification│          │   (JSON)     │              │
│     └──────────────┘          └──────────────┘              │
│            │                                                │
│            ▼                                                │
│  4. Provider tests pass = Contract honored                  │
│                                                             │
└─────────────────────────────────────────────────────────────┘

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Quick Reference: Breaking Changes

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Tooling Selection

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References

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Integration Points

Inputs from:

• API specifications → Contract definitions
• Service architecture → Consumer-provider map
• test-strategy-planning skill → Contract test scope

Outputs to:

• CI/​CD pipeline → Contract verification gates
• API governance → Breaking change detection
• api-design-fundamentals skill → Contract-first design

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Test Scenarios

Scenario 1: Planning contract testing strategy

Query: "Help me design a contract testing strategy for our microservices"

Expected: Skill activates, provides strategy template, guides through service mapping

Scenario 2: Implementing Pact tests

Query: "Show me how to write Pact consumer tests in .NET"

Expected: Skill activates, loads pact-dotnet-implementation.md reference, provides code examples

Scenario 3: CI/​CD integration

Query: "How do I integrate contract testing into our GitHub Actions pipeline?"

Expected: Skill activates, loads matchers-cicd.md reference, provides pipeline examples

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Last Updated: 2025-12-28

Version History

• v1.1.0 (2025-12-28): Refactored to progressive disclosure - extracted implementation to references/
• v1.0.0 (2025-12-26): Initial release