runTest skips your delays, which is why the flaky test passed
Virtual time makes a 30-second timeout instant — and makes a real-dispatcher leak invisible.
testing
23 posts
commonTest runs on every target, which is the point and the cost
One test, five executions. That is how you find platform bugs — and how one flaky test fails five jobs.
It compiles, the test is green, and the screen is a grey box
A structural shell passes an AST scan and a unit test while rendering nothing the mockup specified. Only a rendered check can tell the difference.
The only screenshots worth committing
Golden references are test inputs and belong in version control; run captures are regenerable evidence and do not. Conflating them loses the reference.
A testTag is a contract between the screen and its test
Tests that assert on visible text break on copy edits, which trains people to weaken assertions. A test tag is a deliberate contract that survives rewording.
How do you test a screen whose text is generated?
Snapshot tests die the moment output varies per run. Asserting invariants instead of strings, the vacuous-check trap, and a verdict that means could-not-determine.
adb install -r doesn't kill your app, so your screenshot is a lie
Reinstalling over a running app can leave the old composition on screen. A screenshot taken without a force-stop cannot say which build drew it.
An agent that installs the app and looks at the screen
The capture loop that makes an on-device claim checkable: force-stop, install, launch, capture, hash. Why the order is load-bearing and what it cannot see.
A verification step that can pass while the bug is present is not a verification step
Static checks read what was written; the defect lives in what was drawn. Four artifacts that passed every gate this session and failed the moment someone looked.
An agent that checks the page itself
Giving an agent a real browser removes the slowest loop in web debugging. The first thing that breaks is not your selectors — it is that a headless browser is refused at the edge.
A test that cannot fail is not a test. Mine passed twice.
A RED test fixture that passed because a comment explaining the omission contained the omitted string. The failure mode is generic: any test whose input mentions what it removes.