Count the Robolectric tests, which JaCoCo has never counted
The three #52 test PRs landed 56 new tests and the coverage figure moved 29.8% -> 29.7%. That looked like the tests being worthless. It was the measurement. Robolectric loads every class it touches through its own sandbox classloader, and those classes arrive with no source location. JaCoCo skips no-location classes unless told otherwise, and nothing here told it. So not one Robolectric test has ever contributed coverage in this repo -- and Robolectric is what exercises the framework edge: both workers, the publisher, both ViewModels, every Compose screen. Same commit, same 335 tests, same 0 failures, only the block below added: LINE 652/2194 29.7% -> 1519/2194 69.2% BRANCH 425/1424 29.8% -> 758/1424 53.2% OutputPublisher 0.0% -> 97.5% MainActivityKt 6.8% -> 86.4% ConversionViewModel 0.0% -> 85.4% ConverterScreenKt 6.6% -> 62.8% The discriminator, so this is not cargo cult: inside ConverterScreenKt, `describe` is the one non-Composable and is exercised by a plain JVM test. It reported 8/8 covered while every @Composable in the same class reported 0 -- including ones whose mutations demonstrably failed the build when reverted. Across files the split is exactly Robolectric-vs-not: StagingSweep, tested purely, 100%; OutputPublisher, ConversionViewModel and FailureOutcome, tested under Robolectric, 0%. `excludes = listOf("jdk.internal.*")` is not decoration. Without it JaCoCo walks JDK-internal classes Robolectric has no location for either and the test JVM dies rather than reporting a number. CLAUDE.md's coverage bullet is rewritten, because it was wrong twice over. The figure was an artifact, and the explanation attached to it -- that coverage fell as the suite grew from 11 test files to 43 because the denominator outran the numerator on framework-edge code "the JVM cannot reach" -- described a cause that does not exist. The JVM reaches that code fine. The new tests were disproportionately Robolectric, so each one added denominator and no numerator: the measurement was punishing precisely the tests that were hardest to write, and the conclusion drawn from it was that writing them had not helped. Mutation, run both ways on this branch: remove the block and jacocoTestReport collapses back to 29.7% / 29.8%; restore it and it returns to 69.2% / 53.2%. Two things that were true stay true. There is still no coverage gate, and a floor still needs a settled baseline -- this one just moved 39 points in one build change. And "re-measure before quoting it" was already written down; following it is the only reason this was found.
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@@ -108,12 +108,26 @@ install for code that can never run — and on API 37 the full APK does not fit
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- The `model` package is excluded from `ReturnCount` and `CyclomaticComplexMethod` only. It is the
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decision layer, where one branch is one documented user-visible outcome and the metric counts
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answers rather than complexity. Every other rule still applies there.
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- **Coverage is reported, not gated** — **29.8% of lines (629/2113), 28.7% of branches**, measured
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on `main` 2026-08-23 with `./gradlew :app:jacocoTestReport`. A floor needs a baseline that has
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settled first, and this one has not: the figure **fell** from the ~31% recorded earlier even
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though the JVM suite went from 11 test files to 43. Main source grew 4,114 -> 5,715 lines over
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the same period, so the denominator outran the numerator. Re-measure before quoting it; do not
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assume more tests means a higher percentage here.
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- **Coverage is reported, not gated** — **69.2% of lines (1519/2194), 53.2% of branches**,
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measured 2026-08-24 with `./gradlew :app:jacocoTestReport`.
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**Every figure this file carried before that date was an artifact, roughly half the real one.**
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Robolectric loads classes through its own sandbox classloader with no source location, JaCoCo
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skips no-location classes by default, and nothing told it otherwise — so **not one Robolectric
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test counted**, and Robolectric is what exercises the framework edge here. The
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`isIncludeNoLocationClasses` block in `app/build.gradle.kts` is what fixes it; **do not delete
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it as stray config**, and re-run the numbers if you ever touch it. Same commit, same 335 tests:
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29.7% -> 69.2% with that block alone.
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The old entry also explained the wrong thing. It said coverage **fell** as the suite grew from 11
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test files to 43 because "the denominator outran the numerator" on framework-edge code "the JVM
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cannot reach". The JVM reaches that code fine. What actually happened is that the new tests were
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disproportionately Robolectric, so each one added denominator and no numerator — the measurement
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was punishing exactly the tests that were hardest to write.
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Two things still hold. A floor needs a baseline that has settled, and this one has now moved by
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39 points in a single build change, so it has not. And **re-measure before quoting** — that
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instruction is the only reason this was caught.
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- **Testable code is not done until it is tested.** If a piece is unit testable, it gets unit
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tests before it counts as done. If it is e2e testable, it gets e2e tests. Both clauses apply —
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a change that is both needs both.
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@@ -188,6 +188,30 @@ detekt {
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}
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// Pin the coverage agent rather than inheriting whatever Gradle bundles.
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// Robolectric loads every class it touches through its own sandbox classloader, and those
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// classes arrive with no source location. JaCoCo skips no-location classes by default, so
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// without this block **not one Robolectric test counts** -- and Robolectric is what exercises
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// the framework edge here: the workers, the publisher, both ViewModels, every Compose screen.
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//
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// Measured on e06b082, same 335 tests, same 0 failures, only this block added:
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//
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// LINE 29.7% -> 69.2% OutputPublisher 0.0% -> 97.5%
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// BRANCH 29.8% -> 53.2% ConversionViewModel 0.0% -> 85.4%
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//
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// The discriminator, if this ever looks like superstition: inside ConverterScreenKt, `describe`
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// is the one non-Composable and is exercised by a plain JVM test -- it reported 8/8 covered while
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// every @Composable in the same class reported 0, including ones whose mutations demonstrably
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// failed the build when reverted.
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//
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// `excludes` is not optional. Without it JaCoCo walks JDK-internal classes that Robolectric has
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// no location for either, and the test JVM dies rather than reporting a number.
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tasks.withType<Test>().configureEach {
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extensions.configure<JacocoTaskExtension> {
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isIncludeNoLocationClasses = true
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excludes = listOf("jdk.internal.*")
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}
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}
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jacoco {
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toolVersion = libs.versions.jacoco.get()
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}
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