10.5Testing Fallback Behavior

When the on-device model fails to load (corrupted file, unsupported device, insufficient memory), the app must degrade gracefully to a server-side API.

def test_model_fallback_when_unavailable(driver):
    """App should fall back to server-side API when model fails to load."""
    # Simulate model file corruption
    driver.execute_script("mobile: shell", {
        "command": "rm",
        "args": ["/data/data/com.app/files/ml_model.tflite"]
    })

    # Restart app
    driver.terminate_app("com.app")
    driver.activate_app("com.app")

    # Feature should still work (via server fallback)
    driver.find_element(AppiumBy.ACCESSIBILITY_ID, "classify-image").click()
    result = driver.find_element(AppiumBy.ACCESSIBILITY_ID, "classification-result")
    assert result.is_displayed()

    # Verify fallback indicator is shown
    fallback_badge = driver.find_element(AppiumBy.ACCESSIBILITY_ID, "server-mode-indicator")
    assert fallback_badge.is_displayed()

def test_fallback_to_server_on_low_memory(driver):
    """On low-memory devices, the app should use server-side inference."""
    # Get available memory
    memory_info = driver.execute_script("mobile: shell", {
        "command": "cat",
        "args": ["/proc/meminfo"]
    })

    # If available memory is under threshold, model may not load
    # The app should detect this and use server-side inference
    driver.find_element(AppiumBy.ACCESSIBILITY_ID, "classify-image").click()
    result = driver.find_element(AppiumBy.ACCESSIBILITY_ID, "classification-result")
    assert result.is_displayed()  # Feature works regardless of inference path