`JoinScreenContent` decides the whole join UI in one `when`, and until R38.5 gave it a state
parameter nothing could ask it anything: `Waiting` follows a denied foreground start and `Joined`
follows a finished `ConcatWorker` run, so neither is reachable by driving a real `JoinViewModel`.
`JoinScreenContentTest` used that seam to prove it exists, on one state. This is the matrix behind
it -- seven states, each pinned to the affordance it offers and the callback that affordance is
wired to, asserting on the value handed back rather than on something merely having fired.
Two of the thirteen assert things nothing else in the suite has ever asked.
The rows are read back sorted by their position on screen and compared as an ordered list. A join
is the one flow where the order of the inputs is the content of the output -- the empty state
promises "in the order you want them" -- and `JoinLeafTagsTest` proves only that a row tags itself
with the file it shows, which a reversed list would satisfy just as well.
The progress bar is asserted to be indeterminate, not merely present. It carries no percentage on
purpose, because FFmpeg reports progress against one input's duration and that means nothing across
a concatenation; the converter screen's bar is determinate, so "there is a bar" is exactly the
assertion that would let a fabricated percentage land here unnoticed.
Three mutations, each reverted after:
- `Text(s.message)` -> `Text("")` in `Failed`: "a failed join renders the message it carries" fails
with `could not find any node that satisfies: (Text + InputText + EditableText contains 'The
second file has no audio track, so joining stopped.')`.
- `when (s.strategy)` -> `when (ConcatStrategy.STREAM_COPY)` in `Joined`: "a re-encoded join says
the files differed" fails on the copy for the branch that no longer runs.
- `s.inputs.forEach` -> `s.inputs.reversed().forEach` in `Ready`: the ordering test fails
`expected:<[join.fileRow:intro.mp4, join.fileRow:middle.mp4, join.fileRow:outro.mp4]> but
was:<[join.fileRow:outro.mp4, join.fileRow:middle.mp4, join.fileRow:intro.mp4]>`.
Test-only: no file under `app/src/main` changes, and no tag is added to `TestTags`, because every
string these states render is either already tagged or unambiguous as text. The typographic
characters in the asserted copy -- U+2026 in "Joining N files...", U+2014 in the `Joined` and
Paused lines -- were checked byte-for-byte against `JoinScreen.kt` rather than retyped; an ASCII
lookalike compiles and then quietly matches nothing.
Closes#63.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
JMR-devandClaude Opus 5
02555ceb91