This is a simplified demonstration of a UI Test in Isolation where only one of the tabs is initialised with the desired use case

LaunchesScreenTest.kt

 @Test
    @InternalCoroutinesApi
    fun elementsVisibilityAfterTwoItemsRetrieved() {
        composeTestRule.apply {
            setContent {
                SpaceXTheme {
                    LaunchesScreen(
                        state = LaunchesContract.State(
                            listOf(
                                LaunchUiModel(
                                    "Mission1", "08-12-2021", true, "0", RocketUiModel(
                                        "Rocket1", "Rocket Type1"
                                    ), LinksUiModel("", "", "Youtube Link")
                                ),
                                LaunchUiModel(
                                    "Mission2", "09-12-2021", false, "0", RocketUiModel(
                                        "Rocket2", "Rocket Type2"
                                    ), LinksUiModel("", "WikiPedia Link", "Youtube Link")
                                )
                            ), isLoading = false, isError = false
                        ),
                        effectFlow = flow { emit(LaunchesContract.Effect.ClickableLink.None) } )
                }
            }

            onNodeWithText("Mission1", useUnmergedTree = true)
                .assertIsDisplayed()
            onNodeWithText("Mission2", useUnmergedTree = true)
                .assertIsDisplayed()
            onAllNodesWithContentDescription(
              "Item",
              substring = true,
              useUnmergedTree = true
            ).assertCountEquals(numItemsShowed)
        }
    }