kover

<essential_principles>

Kover is the official Kotlin code coverage tool. The Gradle plugin instruments JVM bytecode during test execution and generates coverage reports. Version 0.9.8.

Core Rules an Agent Must Know

• Apply with id("org.jetbrains.kotlinx.kover") version "0.9.8" in plugins {}. In multi-module builds, apply in root (version inherited by submodules).
• JVM-only coverage. JS and Native targets are not measured. KMP projects only get coverage for common + JVM source sets.
• Android: local unit tests only. On-device instrumented tests are NOT supported.
• Report tasks auto-trigger tests. Running koverHtmlReport runs all relevant test tasks first.
• Multi-module merging uses kover(project(":other")) dependencies in a merging module (typically root). Use full task paths like :koverVerify.
• Android build variants create matching report variants. Append variant name to tasks: koverVerifyDebug.
• Verification rules check coverage bounds. Default: COVERED_PERCENTAGE of LINE grouped by APPLICATION. Use minBound(100) for 100% line coverage.
• verify {} replaces rules; verifyAppend {} adds. Same for filters {} vs filtersAppend {}.
• Filters: excludes beat includes. Use classes(...) for fully-qualified names with */? wildcards. annotatedBy and inheritedFrom are Kover-only (not JaCoCo).
• Instrumentation issues (VerifyError, No instrumentation registered!) — exclude the class from instrumentation. Side effect: 0% coverage for that class.
• require() with string interpolation creates uncoverable bytecode branches. Use explicit if (...) throw instead.
• The test source set is excluded by default. Use sources { excludedSourceSets } for additional exclusions.