EditTextTest.kt

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.EditText
import androidx.fragment.app.Fragment
import androidx.fragment.app.testing.launchFragmentInContainer
import androidx.test.espresso.Espresso.onView
import androidx.test.espresso.action.ViewActions.typeText
import androidx.test.espresso.matcher.ViewMatchers.withClassName
import com.google.common.truth.Truth.assertThat
import org.hamcrest.Matchers
import org.junit.Test
import org.junit.runner.RunWith
import org.robolectric.RobolectricTestRunner
import org.robolectric.annotation.Config
import org.robolectric.annotation.Implementation
import org.robolectric.annotation.Implements
import org.robolectric.annotation.RealObject
import org.robolectric.shadow.api.Shadow
import org.robolectric.shadows.ShadowView

@Implements(className="android.widget.Editor\$InsertionHandleView")
class ShadowInsertionHandleView: ShadowView() { {
  @RealObject
  private lateinit var realInsertionHandleView: Object

  @Suppress("unused", "ProtectedInFinal") // Used by Robolectric and protected recommended to limit api surface.
  @Implementation
  protected fun getCurrentCursorOffset(): Int {
    return try {
      Shadow.directlyOn(
        realInsertionHandleView,
        "android.widget.Editor\$InsertionHandleView",
        "getCurrentCursorOffset"
      )
    } catch (ex: Exception) {
      0
    }
  }
}

/**
 * Class with same class structure as [android.widget.Editor.InsertionHandleView] to demonstrate that inner classes
 * can normally access parent this during construction.
 */
class Editor(val mTextView: EditText) {

  fun onTouchUpEvent() {
    InsertionPointCursorController().show()
  }
  abstract inner class HandleView {

    init {
        updateDrawable(true)
    }

    open fun updateDrawable(updateDrawableWhenDragging: Boolean) {
      println("getCurrentCursorOffset " + getCurrentCursorOffset())
    }

    abstract fun getCurrentCursorOffset(): Int
  }
  inner class InsertionHandleView: HandleView() {
    override fun updateDrawable(updateDrawableWhenDragging: Boolean) {
      super.updateDrawable(updateDrawableWhenDragging)
      println("hi")
    }

    override fun getCurrentCursorOffset(): Int {
      return mTextView.selectionStart
    }
  }

  inner class InsertionPointCursorController  {
    fun show() {
      getHandle()
    }
    fun getHandle(): InsertionHandleView {
      return InsertionHandleView()
    }
  }
}

@RunWith(RobolectricTestRunner::class)
@Config(shadows = [ShadowInsertionHandleView::class])
class EditTextTest {
  @Test
  fun innerClasses_whenUnderConstruction_canAccessParentThis() {
    val scenario = launchFragmentInContainer<TestFragment>()
    scenario.onFragment {
      val underTest = it.view as EditText
      Editor(underTest).onTouchUpEvent()
    }
  }

  @Test
  fun editText_whenClickedOnWithText_doesNotCrash() {
    val scenario = launchFragmentInContainer<TestFragment>()
    scenario.onFragment {
      val underTest = it.view as EditText
      onView(withClassName(Matchers.equalTo(underTest::class.qualifiedName)))
        .perform(typeText("Hello "))
        .perform(typeText("c")) // No crash anymore

      assertThat(underTest.text.toString()).isEqualTo("Hello c")
    }
  }

  class TestFragment : Fragment() {
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
      return EditText(requireContext())
    }
  }
}