Path Coverage or Mutation Testing?

A comparison of path coverage and mutation testing as methods for assessing test suite quality in PHP. Path coverage measures structural completeness by tracking all execution paths, while mutation testing evaluates whether tests can actually detect real errors via the Mutation Score Indicator (MSI). The author explains that code coverage is quantitative (how much code is executed) while mutation testing is qualitative (how well tests catch bugs). Practically, the author prefers mutation testing with Infection over path coverage due to better reporting, lower resource requirements, and more actionable output, reserving path coverage for specific analysis needs.