Treat coverage as a floor

How to do it

Set a minimum at today's coverage, rounded down to a whole number, in the runner, such as Vitest coverage.thresholds, Jest coverageThreshold or pytest-cov --cov-fail-under. Raise it as coverage grows. Read the report for risky code with no tests, rather than chasing a total.

Example

// vitest.config.js
export default {
  test: {
    coverage: { provider: 'v8', thresholds: { lines: 80, branches: 75 } },
  },
};

# pyproject.toml for pytest-cov and coverage.py
[tool.coverage.run]
branch = true

[tool.coverage.report]
fail_under = 80

// build.gradle.kts with JaCoCo for Java and Kotlin
tasks.jacocoTestCoverageVerification {
    violationRules { rule { limit { minimum = "0.80".toBigDecimal() } } }
}
tasks.check { dependsOn(tasks.jacocoTestCoverageVerification) }

How to check

The test run fails when coverage falls below the set minimum.