ADR-08 Enforce-Branch-Coverage

Context

High test coverage is a key factor for ensuring software quality. To ensure a consistently high quality of our software, we want to define a minimum for test coverage. Branch coverage is a useful metric here, as it ensures that not only statements but also different execution paths in the code are tested.

Decision

We are setting a minimum of 80% branch coverage.

We allow justified exceptions for hard-to-test code and unreasonable tests, but the reason has to be documented in an inline-comment. Generated code is excluded. For ui components, coverage will not be considered and the UI will be tested only rudimentarily where it is dynamic (e.g., conditional rendering, DOM updates).

Consequences

• All new code must be written with sufficient tests to meet the coverage target.
• Developers need to be mindful of the coverage of their code and write meaningful tests.
• This increases the quality of our software and reduces the risk of regressions.