Why can't I use gradle task connectedDebugAndroidTest in my build script?

I can refer to connectedCheck task (which came from android plugin) from my build script:

connectedCheck.finalizedBy AndroidShowTestResults

But trying to use connectedDebugAndroidTest (which came from android plugin too)

connectedDebugAndroidTest.finalizedBy AndroidShowTestResults

gives me

Error:(48, 0) Could not find property 'connectedDebugAndroidTest' on project ':app'.

And if I try

task connectedDebugAndroidTest << {print '123'}

it curses me with

Error:Cannot add task ':app:connectedDebugAndroidTest' as a task with that name already exists.

I don't undestand why I cannot refer to connectedDebugAndroidTest?

Available gradle tasks are shown below: