How to overcome this build error when trying to run jetpack compose instrumentation tests

I've followed the jetpack compose navigation codelab. Everything was going well until it came to testing the NavHost in step 7. When trying to run the tests, I get the following error and stack trace :

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:processDebugAndroidTestManifest'.
> Manifest merger failed with multiple errors, see logs

* Try:
Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:processDebugAndroidTestManifest'.
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.lambda$executeIfValid$1(ExecuteActionsTaskExecuter.java:188)
    at org.gradle.internal.Try$Failure.ifSuccessfulOrElse(Try.java:263)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeIfValid(ExecuteActionsTaskExecuter.java:186)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:174)
    at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:109)
    .....
Caused by: java.lang.RuntimeException: Manifest merger failed with multiple errors, see logs
    at com.android.build.gradle.tasks.ProcessTestManifest.handleMergingResult(ProcessTestManifest.kt:331)
    at com.android.build.gradle.tasks.ProcessTestManifest.mergeManifestsForTestVariant(ProcessTestManifest.kt:301)
    at com.android.build.gradle.tasks.ProcessTestManifest.doFullTaskAction(ProcessTestManifest.kt:111)
    .....

There is a problem with the merged Manifest, but within the androidTest directory I have no Manifest, so as far as i can see, I have no control over what's in the generated one.

I can see the Merged Manifest from the main directory and there are no errors present in there. I can see the generated manifest in the build folder and it does display a load of errors.

Is there some technique I could use to attempt to resolve this?

EDIT: Further investigation shows the problem as

android-compose-codelabs/NavigationCodelab/app/build/intermediates/tmp/manifest/androidTest/debug/tempFile1ProcessTestManifest6269584048200983460.xml Error:
    android:exported needs to be explicitly specified for <activity>. Apps targeting Android 12 and higher are required to specify an explicit value for `android:exported` when the corresponding component has an intent filter defined. See https://developer.android.com/guide/topics/manifest/activity-element#exported for details.

android:exported has been declared in the main/AndroidManifest.xml as expected, and it is also present in each component in the generated merged manifest for androidTest.