How to Choose the Right Code Coverage Tool: 10 Essential Criteria

Background: To develop safe, reliable software, testing is essential; without sufficient testing, software safety and correctness cannot be assured. Code coverage measurement indicates the proportion of code exercised by tests, e.g., running three of four possible options yields 75% coverage.

Industry standards often require specific coverage levels for certification; lacking proof of adequate coverage can prevent product certification.

1. Independent of Compiler

A tool that works regardless of the compiler can be used across projects and remains viable when compilers change, offering greater flexibility and investment value.

2. Ease of Use

Simple, unobtrusive tools increase adoption; ideally they run in the background without adding burden during testing.

3. Understandable Coverage Reports

Reports should clearly show which code parts are tested and which are not, enabling targeted testing and avoiding unnecessary work.

4. Support for High Safety-Critical Coverage Levels

Safety-critical domains (e.g., ISO 26262, DO-178C, EN-50128) demand high coverage such as MC/DC; tools must support these levels, not just decision or branch coverage.

5. Flexible Integration

The tool should integrate smoothly with diverse development environments and build pipelines, preferably offering command‑line usage for automation.

6. Low Overhead

Instrumentation adds code size; on memory‑constrained embedded targets, the tool’s overhead should be minimal.

7. Multi‑Language Support

Supporting many programming languages ensures the tool remains useful as projects evolve or adopt new languages.

8. Support for “Creative” Programming

Tools should handle unconventional or highly nested language constructs without failing.

9. Suitability for Safety‑Critical Development

For safety‑critical software, the entire toolchain must be qualified; the coverage tool should have proven use in such projects and provide certification kits.

10. Evaluation of License, Support, and References

During tool evaluation, assess licensing terms, quality of technical support, documentation, training, and customer references to gauge reliability and popularity.