Android Studio : Cannot use class from src in Unit tests - android-studio

Question

since the last Update (of Android Studio ? or Gradle ?) I cannot import code from prod in my tests classes.
A few months ago, the tests were working without any problems.
I can launch the tests, using gradle in command line, or using AndroidStudio test runner. And it work nice : it passes when the code is ok, it fails when there is a bug.
But the auto-completion isn't working, the class, methods ... are red.
I cannot click on an object to navigate to the declaration ... and so on.
And the AndroidStudio automatic quickfix is : "add dependency on module xxx"
which add a line in the gradle file :
implementation project(path: ':app')
I have the same problem on several project, with gradle 6.1.1 or 7.2.1
AndroidStudio version is :
Chipmunk, 2021.2.1 patch 1
built on May 18 2022
the unit test, in app/src/test/java/com/apackage/ASimpleTest.kt
package com.apackage
import org.junit.Test
import kotlin.test.assertEquals
class ASimpleTest {
#Test
fun aTest(){
val plop = AClass()
assertEquals(1, plop.aMethod())
}
}
the class in app/src/main/java/com/apackage/AClass.kt:
package com.apackage
class AClass {
fun aMethod() = 1
}
I have no problem calling a method in the same folder as the tests.
The problem is test/main folder calling src/main