A gap audit over the eight branches merged together looked for lines still
never executed and asked, for each, whether something already accounts for it.
Everything mapped except one: `ConcatWorker.kt:42`, the refusal of a join with
fewer than two inputs.
Its neighbour maps. `ConcatWorker.kt:40` -- the missing-URI-array arm, two lines
above -- is covered on the device by
`UnopenableUriTest.aJoinWithNoInputArrayFailsWithAMessage`. That is invisible to
JaCoCo, which measures `testDebugUnitTest` only, so the report shows both arms
cold and cannot distinguish the one that is e2e-covered from the one nothing
touches. Only reading the androidTest source separates them.
`grep` says nothing in either source set mentions "Pick at least two files to
join." Two tests here now do:
- `a join of a single file is refused with a message rather than joined` pins
the verdict and the message together, via `Failure.equals`, for the reason the
file's header already gives.
- `a join of two files is not refused for its count` is the control that puts
the assertion on the boundary rather than on the string. It refuses the
*space* rather than letting the job run: the next thing past the count guard
is `ConcatEngine`, which is native, and `NamingPublisher`'s KDoc already
records that no JVM test gets past it. A failure carrying the space message is
proof execution reached line 57, which is proof it cleared line 42, at no
engine cost.
Reachability is the header's argument plus one of its own: `request(...)` takes
a `List<Uri>` and checks nothing about its length, so a one-item join is a
well-formed call rather than a corrupted queue entry.
Mutations, each killing exactly the test it should:
| mutation | red |
|---|---|
| guard deleted outright | `a join of a single file is refused...` |
| `uris.size < 2` -> `< 3` | `a join of two files is not refused for its count` |
Restored, both green. Gate green: assembleDebug, testDebugUnitTest,
compileDebugAndroidTestKotlin, ktlintCheck, detekt, lintDebug.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Both exits were cold, and both are reachable for the same reason: a job
does not have to come from the picker. WorkManager keeps work for about a
week, so a downgrade or rollback hands this build a job enqueued by
another one, and request(...) is callable directly.
:62 -- a missing KEY_INPUT_URI -- was untested everywhere, JVM and device.
The nearest e2e test, ForcedFailureTest.aMissingInputFailsRatherThanCrashing,
passes a URI pointing at a file that does not exist, which reaches the
engine and fails much later with a different message.
:124-126 -- the Validation.Invalid refusal -- had no test at all, though
its comment names both arrival paths it exists for.
Five tests, in a new file because both are about the *message*. A refusal
that fails with empty output Data renders the UI's generic "Conversion
failed." with nothing else to say, which is the defect shape
DeniedForegroundStartTest records from the device pass; asserting the
verdict alone would pass against exactly that.
Two of the five are there to stop the others passing for the wrong reason:
`a refused spec never reaches an engine` says it failed *before*
converting rather than during, and `a valid spec is not refused` is the
control -- without it every assertion here would still pass against a
worker that refused everything.
Three mutations, three red:
change the no-input message no-input message test
drop the validation refusal both refusal tests
validate but keep converting both refusal tests
L61-62 and L123-126 are now fully covered, branches included.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
JMR-dev
