Contract Testing
Contract Testing ensures that different parties within a system are compatible by testing the contracts between these groups.
Classification
- ComplexityMedium
- Impact areaTechnical
- Decision typeArchitectural
- Organizational maturityIntermediate
Technical context
Principles & goals
Use cases & scenarios
Compromises
- Incorrect contracts can lead to system failures.
- Insufficient tests can leave undetected errors.
- Excessive effort for maintaining tests.
- Documentation of Contracts
- Regular Maintenance of Tests
- Involving all stakeholders in the process
I/O & resources
- API Specifications
- Test Scripts
- Results of Previous Tests
- Verification Reports
- Feedback from Development Teams
- Corrective Requests
Description
Contract Testing is a practical approach that enables teams to automatically ensure that their implementations conform to the established contracts. These tests provide assurance in the communication between different systems and promote a better understanding among development teams.
✔Benefits
- Increased assurance in interoperability.
- Early detection of integration errors.
- Improved collaboration between teams.
✖Limitations
- Can be complex with many changing teams.
- Test cases must be continuously updated.
- Requires a deep understanding of API architecture.
Trade-offs
Metrics
- Number of Tested Contracts
Measures how many contracts have been validated through testing.
- Error Rate
Proportion of errors in the tested implementations.
- Test Coverage Rate
Measures what percentage of contracts have been tested.
Examples & implementations
E-Commerce API Contract
An example of contract testing in an e-commerce system ensuring interoperability between different payment services.
Healthcare Microservices
Case study on the application of contract testing in a network of healthcare services to ensure consistent data transfer.
Financial Services API
Contract testing in a financial application to avoid errors in API integrations.
Implementation steps
Set up Test Environments
Define Testing Policies
Conduct the Tests
⚠️ Technical debt & bottlenecks
Technical debt
- Outdated Testing Infrastructure
- Insufficient Tool Support
- Lack of Integration with CI/CD Pipelines
Known bottlenecks
Misuse examples
- Use of Poor Style in Contract Definitions
- Neglecting Error Messages
- Poor Communication Between Teams
Typical traps
- Overcomplexity of Tests
- Misunderstandings Due to Poor Documentation
- Additional Bureaucratic Hurdles
Required skills
Architectural drivers
Constraints
- • Limited Testing Resources
- • Deadlines for Test Implementations
- • Reporting Guidelines