For #14980 - Effectively disable tabs tray STATE_HALF_EXPANDED (#16052)

STATE_HALF_EXPANDED cannot be disabled while also keeping fitToContents = true
based on which the tabs tray layout is currently set.
To work around this we'll set a a minuscule height for the tab tray when in
this state and then immediately advance to STATE_HIDDEN so to make it
imperceptible to the users.
Since I couldn't write unit tests because of InflateExceptions in Robolectric
I've written UI tests to protect against regressions.

app/src/androidTest/java/org/mozilla/fenix/helpers/idlingresource/BottomSheetBehaviorStateIdlingResource.kt

@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.helpers.idlingresource
+
+import android.view.View
+import androidx.test.espresso.IdlingResource
+import androidx.test.espresso.IdlingResource.ResourceCallback
+import com.google.android.material.bottomsheet.BottomSheetBehavior
+import com.google.android.material.bottomsheet.BottomSheetBehavior.BottomSheetCallback
+
+class BottomSheetBehaviorStateIdlingResource(behavior: BottomSheetBehavior<*>) :
+    BottomSheetCallback(), IdlingResource {
+
+    private var isIdle: Boolean
+    private var callback: ResourceCallback? = null
+
+    override fun onStateChanged(bottomSheet: View, newState: Int) {
+        val wasIdle = isIdle
+        isIdle = isIdleState(newState)
+        if (!wasIdle && isIdle && callback != null) {
+            callback!!.onTransitionToIdle()
+        }
+    }
+
+    override fun onSlide(bottomSheet: View, slideOffset: Float) {
+        // no-op
+    }
+
+    override fun getName(): String {
+        return BottomSheetBehaviorStateIdlingResource::class.java.simpleName
+    }
+
+    override fun isIdleNow(): Boolean {
+        return isIdle
+    }
+
+    override fun registerIdleTransitionCallback(callback: ResourceCallback) {
+        this.callback = callback
+    }
+
+    private fun isIdleState(state: Int): Boolean {
+        return state != BottomSheetBehavior.STATE_DRAGGING &&
+            state != BottomSheetBehavior.STATE_SETTLING &&
+            // When detecting STATE_HALF_EXPANDED we immediately transit to STATE_HIDDEN.
+            // Consider this also an intermediary state so not idling.
+            state != BottomSheetBehavior.STATE_HALF_EXPANDED
+    }
+
+    init {
+        behavior.addBottomSheetCallback(this)
+        val state = behavior.state
+        isIdle = isIdleState(state)
+    }
+}

app/src/androidTest/java/org/mozilla/fenix/helpers/matchers/BottomSheetBehaviorMatchers.kt

@@ -0,0 +1,39 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.helpers.matchers
+
+import android.view.View
+import androidx.test.espresso.matcher.BoundedMatcher
+import com.google.android.material.bottomsheet.BottomSheetBehavior
+import org.hamcrest.Description
+
+class BottomSheetBehaviorStateMatcher(private val expectedState: Int) :
+    BoundedMatcher<View, View>(View::class.java) {
+
+    override fun describeTo(description: Description?) {
+        description?.appendText("BottomSheetBehavior in state: \"$expectedState\"")
+    }
+
+    override fun matchesSafely(item: View): Boolean {
+        val behavior = BottomSheetBehavior.from(item)
+        return behavior.state == expectedState
+    }
+}
+
+class BottomSheetBehaviorHalfExpandedMaxRatioMatcher(private val maxHalfExpandedRatio: Float) :
+    BoundedMatcher<View, View>(View::class.java) {
+
+    override fun describeTo(description: Description?) {
+        description?.appendText(
+            "BottomSheetBehavior with an at max halfExpandedRation: " +
+                "$maxHalfExpandedRatio"
+        )
+    }
+
+    override fun matchesSafely(item: View): Boolean {
+        val behavior = BottomSheetBehavior.from(item)
+        return behavior.halfExpandedRatio <= maxHalfExpandedRatio
+    }
+}

app/src/androidTest/java/org/mozilla/fenix/ui/TabbedBrowsingTest.kt

@@ -6,6 +6,7 @@ package org.mozilla.fenix.ui
 
 import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.uiautomator.UiDevice
+import com.google.android.material.bottomsheet.BottomSheetBehavior
 import okhttp3.mockwebserver.MockWebServer
 import org.junit.After
 import org.junit.Before
@@ -254,6 +255,31 @@ class TabbedBrowsingTest {
         }
     }
 
+    @Test
+    fun verifyTabTrayNotShowingStateHalfExpanded() {
+        homeScreen { }.dismissOnboarding()
+
+        navigationToolbar {
+        }.openTabTray {
+            verifyNoTabsOpened()
+            // With no tabs opened the state should be STATE_COLLAPSED.
+            verifyBehaviorState(BottomSheetBehavior.STATE_COLLAPSED)
+            // Need to ensure the halfExpandedRatio is very small so that when in STATE_HALF_EXPANDED
+            // the tabTray will actually have a very small height (for a very short time) akin to being hidden.
+            verifyHalfExpandedRatio()
+        }.clickTopBar {
+        }.waitForTabTrayBehaviorToIdle {
+            // Touching the topBar would normally advance the tabTray to the next state.
+            // We don't want that.
+            verifyBehaviorState(BottomSheetBehavior.STATE_COLLAPSED)
+        }.advanceToHalfExpandedState {
+        }.waitForTabTrayBehaviorToIdle {
+            // TabTray should not be displayed in STATE_HALF_EXPANDED.
+            // When advancing to this state it should immediately be hidden.
+            verifyTabTrayIsClosed()
+        }
+    }
+
     @Test
     fun verifyEmptyTabTray() {
         homeScreen { }.dismissOnboarding()

app/src/androidTest/java/org/mozilla/fenix/ui/robots/TabDrawerRobot.kt

@@ -7,13 +7,17 @@
 package org.mozilla.fenix.ui.robots
 
 import android.content.Context
+import android.view.View
 import androidx.recyclerview.widget.RecyclerView
 import androidx.test.core.app.ApplicationProvider
 import androidx.test.espresso.Espresso
 import androidx.test.espresso.Espresso.onView
 import androidx.test.espresso.NoMatchingViewException
+import androidx.test.espresso.UiController
+import androidx.test.espresso.ViewAction
 import androidx.test.espresso.action.ViewActions
 import androidx.test.espresso.action.ViewActions.click
+import androidx.test.espresso.assertion.ViewAssertions.doesNotExist
 import androidx.test.espresso.assertion.ViewAssertions.matches
 import androidx.test.espresso.contrib.RecyclerViewActions
 import androidx.test.espresso.matcher.ViewMatchers
@@ -28,14 +32,19 @@ import androidx.test.uiautomator.By.text
 import androidx.test.uiautomator.UiDevice
 import androidx.test.uiautomator.Until
 import androidx.test.uiautomator.Until.findObject
+import com.google.android.material.bottomsheet.BottomSheetBehavior
 import org.hamcrest.CoreMatchers.allOf
 import org.hamcrest.CoreMatchers.anyOf
 import org.hamcrest.CoreMatchers.containsString
+import org.hamcrest.Matcher
 import org.mozilla.fenix.R
 import org.mozilla.fenix.helpers.TestAssetHelper
 import org.mozilla.fenix.helpers.TestAssetHelper.waitingTime
 import org.mozilla.fenix.helpers.click
 import org.mozilla.fenix.helpers.ext.waitNotNull
+import org.mozilla.fenix.helpers.idlingresource.BottomSheetBehaviorStateIdlingResource
+import org.mozilla.fenix.helpers.matchers.BottomSheetBehaviorHalfExpandedMaxRatioMatcher
+import org.mozilla.fenix.helpers.matchers.BottomSheetBehaviorStateMatcher
 
 /**
  * Implementation of Robot Pattern for the home screen menu.
@@ -52,6 +61,10 @@ class TabDrawerRobot {
     fun verifyNewTabButton() = assertNewTabButton()
     fun verifyTabTrayOverflowMenu(visibility: Boolean) = assertTabTrayOverflowButton(visibility)
 
+    fun verifyTabTrayIsClosed() = assertTabTrayDoesNotExist()
+    fun verifyHalfExpandedRatio() = assertMinisculeHalfExpandedRatio()
+    fun verifyBehaviorState(expectedState: Int) = assertBehaviorState(expectedState)
+
     fun closeTab() {
         closeTabButton().click()
     }
@@ -126,9 +139,7 @@ class TabDrawerRobot {
         fun closeTabDrawer(interact: BrowserRobot.() -> Unit): BrowserRobot.Transition {
             mDevice.waitForIdle(waitingTime)
 
-            // Dismisses the tab tray bottom sheet with 2 handle clicks
             onView(withId(R.id.handle)).perform(
-                click(),
                 click()
             )
             BrowserRobot().interact()
@@ -169,6 +180,52 @@ class TabDrawerRobot {
             BrowserRobot().interact()
             return BrowserRobot.Transition()
         }
+
+        fun clickTopBar(interact: TabDrawerRobot.() -> Unit): Transition {
+            onView(withId(R.id.topBar)).click()
+            TabDrawerRobot().interact()
+            return Transition()
+        }
+
+        fun advanceToHalfExpandedState(interact: TabDrawerRobot.() -> Unit): Transition {
+            onView(withId(R.id.tab_wrapper)).perform(object : ViewAction {
+                override fun getDescription(): String {
+                    return "Advance a BottomSheetBehavior to STATE_HALF_EXPANDED"
+                }
+
+                override fun getConstraints(): Matcher<View> {
+                    return ViewMatchers.isAssignableFrom(View::class.java)
+                }
+
+                override fun perform(uiController: UiController?, view: View?) {
+                    val behavior = BottomSheetBehavior.from(view!!)
+                    behavior.state = BottomSheetBehavior.STATE_HALF_EXPANDED
+                }
+            })
+            TabDrawerRobot().interact()
+            return Transition()
+        }
+
+        fun waitForTabTrayBehaviorToIdle(interact: TabDrawerRobot.() -> Unit): Transition {
+            var behavior: BottomSheetBehavior<*>? = null
+            onView(withId(R.id.tab_wrapper)).perform(object : ViewAction {
+                override fun getDescription(): String {
+                    return "Postpone actions to after the BottomSheetBehavior has settled"
+                }
+
+                override fun getConstraints(): Matcher<View> {
+                    return ViewMatchers.isAssignableFrom(View::class.java)
+                }
+
+                override fun perform(uiController: UiController?, view: View?) {
+                    behavior = BottomSheetBehavior.from(view!!)
+                }
+            })
+            runWithIdleRes(BottomSheetBehaviorStateIdlingResource(behavior!!)) {
+                TabDrawerRobot().interact()
+            }
+            return Transition()
+        }
     }
 }
 
@@ -239,6 +296,21 @@ private fun assertTabTrayOverflowButton(visible: Boolean) =
     onView(withId(R.id.tab_tray_overflow))
         .check(matches(withEffectiveVisibility(visibleOrGone(visible))))
 
+private fun assertTabTrayDoesNotExist() {
+    onView(withId(R.id.tab_wrapper))
+        .check(doesNotExist())
+}
+
+private fun assertMinisculeHalfExpandedRatio() {
+    onView(withId(R.id.tab_wrapper))
+        .check(matches(BottomSheetBehaviorHalfExpandedMaxRatioMatcher(0.001f)))
+}
+
+private fun assertBehaviorState(expectedState: Int) {
+    onView(withId(R.id.tab_wrapper))
+        .check(matches(BottomSheetBehaviorStateMatcher(expectedState)))
+}
+
 private fun tab(title: String) =
     onView(
         allOf(

app/src/main/java/org/mozilla/fenix/tabtray/TabTrayView.kt

@@ -117,6 +117,9 @@ class TabTrayView(
 
         toggleFabText(isPrivate)
 
+        view.topBar.setOnClickListener {
+            // no-op, consume the touch event to prevent it advancing the tray to the next state.
+        }
         behavior.addBottomSheetCallback(object : BottomSheetBehavior.BottomSheetCallback() {
             override fun onSlide(bottomSheet: View, slideOffset: Float) {
                 if (interactor.onModeRequested() is Mode.Normal && !hasAccessibilityEnabled) {
@@ -133,6 +136,10 @@ class TabTrayView(
                     components.analytics.metrics.track(Event.TabsTrayClosed)
                     interactor.onTabTrayDismissed()
                 }
+                // We only support expanded and collapsed states. Don't allow STATE_HALF_EXPANDED.
+                else if (newState == BottomSheetBehavior.STATE_HALF_EXPANDED) {
+                    behavior.state = BottomSheetBehavior.STATE_HIDDEN
+                }
             }
         })
 

app/src/main/res/values/styles.xml

@@ -624,7 +624,8 @@
         <item name="behavior_fitToContents">false</item>
         <item name="behavior_expandedOffset">80</item>
         <item name="behavior_skipCollapsed">false</item>
-        <item name="behavior_halfExpandedRatio">0.4</item>
+        <!-- Effectively disable STATE_HALF_EXPANDED by having the tray have a minuscule height in this state -->
+        <item name="behavior_halfExpandedRatio">0.001</item>
     </style>
 
     <style name="TopSite.Favicon" parent="Mozac.Widgets.Favicon">