jevtest

Plain-English end-to-end tests for Android and iOS apps. Write what a user does and what they should see; Jev works out the taps. Every run is recorded, so CI replays it exactly, offline.

login.yaml

app: build/app-debug.apk
device: { android: emulator-5554 }

tests:
  - name: Sign in
    fresh: true
    steps:
      - do: Sign in with email "${DEMO_EMAIL}" and password "${DEMO_PASSWORD}"
        expect: The home screen is showing
        see: Welcome, ${DEMO_EMAIL}

$ jevtest run login.yaml --lock frozen --out results
jevtest 0.6.0 · android · emulator-5554 · dev.jevtest.jevtest_demo · typesafe/jev-1.13 · lockfile: frozen

▶ Sign in
  ✓ do: Sign in with email "${DEMO_EMAIL}" and password "${DEMO_PASSWORD}" (2.6s) — 3 action(s)
      → type "${DEMO_EMAIL}" into text_field 'Email'  (confidence 0.83)
      → type "${DEMO_PASSWORD}" into password_field 'Password'  (confidence 0.76)
      → tap button 'Sign in'  (confidence 0.93)
      → done  (confidence 0.96)
      ✓ expect: The home screen is showing — Jev 0.95
      ✓ see: Welcome, ${DEMO_EMAIL}
  PASS Sign in (7.1s)

1/1 passed in 7s
Jev: 5 decisions, 5 from lockfile, 0 asked live in 0.0s (0% of run time), $0.0000

Real output from the demo app on an Android emulator. ${DEMO_PASSWORD} comes from .env: logs and reports only ever show the name.

Get started Writing tests

Why jevtest

• Tests read like the spec

  One action, then what should be true. do: takes a plain-English goal; tap:, type:, swipe: and 20 more are there when you want exact control.

• Deterministic by design

  Every Jev decision is recorded in a lockfile. --lock frozen replays a run exactly, with no network and no API key. A changed screen is a new question, never a stale answer.

• Nothing assumed

  No default device, no guessing what a typo meant, and settings with good defaults and strict limits. Anything missing or wrong fails before the run starts, and says exactly what to fix.

• Real apps, real phones

  Android emulators and phones, iOS simulators and iPhones. Native, Flutter, React Native, and in-app WebViews, all driven the same way. jevtest never turns off animations or changes the device.

• No sleeps

  It waits for the screen to stop changing, reacting to the device, not a timer. Content that loads late passes when it arrives.

• Built for CI

  JUnit XML, a JSON report of every step and decision, screenshots of failures, one exit code. Split tests across several devices and run them at the same time.

How it works, in one picture

flowchart LR
    A[Step: do / tap / expect] --> B[Read the screen<br/>accessibility tree]
    B --> C[Screen as text<br/>elements + positions]
    C --> D{Lockfile has<br/>this exact question?}
    D -- yes --> F[Recorded answer]
    D -- no --> E[Ask Jev<br/>choose from options] --> F
    F --> G[Act on the device<br/>adb / XCUITest]
    G --> H[Wait until the screen<br/>stops changing]
    H --> B

Jev is TypeSafe's decision model: it reads text and chooses from the options jevtest gives it. It never writes free text, so what gets typed always comes from your test file. More on how it works.

Status

jevtest is new. It is tested end to end on a Flutter demo app with native and web screens, on the Android emulator (API 37), a Pixel 4a (Android 13), iOS simulators (iOS 26) and an iPhone 17 (iOS 27), with 100% line and branch coverage in its unit tests. Issues and pull requests are welcome.