Give a better error message with you omit `@get:Rule`

[yogurtearl]

If you forget @get:Rule, it should provide a message that says "Did you forgot @get:Rule? "

Consider this code:

    // forgot to put the @get:Rule
    val composeTestRule = createComposeRule()

    @Test
    fun `test compose stuff`() = with(composeTestRule) {
        setContent {
              Text("Hi there") 
        }
    }

Without @get:Rule you get this:

java.lang.NullPointerException
at androidx.test.internal.util.Checks.checkNotNull(Checks.java:41)
at androidx.test.ext.junit.rules.ActivityScenarioRule.getScenario(ActivityScenarioRule.java:127)
at androidx.compose.ui.test.junit4.AndroidComposeTestRule_androidKt.getActivityFromTestRule(AndroidComposeTestRule.android.kt:398)
at androidx.compose.ui.test.junit4.AndroidComposeTestRule_androidKt.access$getActivityFromTestRule(AndroidComposeTestRule.android.kt:1)
at androidx.compose.ui.test.junit4.AndroidComposeTestRule_androidKt$createAndroidComposeRule$1.invoke(AndroidComposeTestRule.android.kt:126)
at androidx.compose.ui.test.junit4.AndroidComposeTestRule_androidKt$createAndroidComposeRule$1.invoke(AndroidComposeTestRule.android.kt:126)
at androidx.compose.ui.test.junit4.AndroidComposeTestRule$special$$inlined$AndroidComposeUiTestEnvironment$1.getActivity(ComposeUiTest.android.kt:215)
at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$AndroidComposeUiTestImpl.getActivity(ComposeUiTest.android.kt:449)
at androidx.compose.ui.test.AndroidComposeUiTestEnvironment$AndroidComposeUiTestImpl.setContent(ComposeUiTest.android.kt:538)
at androidx.compose.ui.test.junit4.AndroidComposeTestRule.setContent(AndroidComposeTestRule.android.kt:381)

Should add something like this to ActivityScenarioRule.getScenario to give a hint:

        checkNotNull(scenario) { "scenario was null, did you forgot @get:Rule somewhere?" }