What is being measured?

Emerge's performance testing allows customization of both the scenario (what UI test is ran) and the measure (what critical section within that scenario is being measured).

This table summarizes what is measured in common situations.

Test annotation	Measure name	Description
[No test]	Time to initial display	By default if no specific test class is known the scenario is app startup and the measure is time to initial display.
`@EmergeStartupTest`	Time to initial display	You can override the default startup UI test with a custom startup scenario. This allows testing multiple entry points for example. See more .
`@EmergeTest()`	Duration of the test method	When defining a custom perf test, the default measure is the duration of the test.
`@EmergeTest(spans = ["my_custom_span"])`	Duration of the `my_custom_span` span	By explicitly setting a span to measure we can measure some smaller critical section in the app within the test duration. See more .