android testing state flow test block

Question

I am writing tests for my view model and I encountered an issue, did some research and I found this on docs and using that I fixed my problem but have my question unanswered

https://developer.android.com/kotlin/flow/test#turbine

@Test
fun usingTurbine() = runTest {
    val dataSource = FakeDataSource()
    val repository = Repository(dataSource)

    repository.scores().test {
        // Make calls that will trigger value changes only within test{}
        dataSource.emit(1)
        assertEquals(10, awaitItem())

        dataSource.emit(2)
        awaitItem() // Ignore items if needed, can also use skip(n)

        dataSource.emit(3)
        assertEquals(30, awaitItem())
    }
}

here in test {} block, it says

Make calls that will trigger value changes only within test{}

is there any reason why we should make calls that can impact value change in state flow inside test{} block, but not outside?(maybe before test block), for example above we can locate dataSource.emit(1) before test{} block, but it will not work, but I would like to know the reason why this won't work there