[Test Week] Add ViewCacheTest

Number of new tested methods: 3

Bug: 353303621
Test: This is the unit test
Flag: NONE - unit test
Change-Id: I235ba375db12b9f3fac6f204018b32e692835eab

src/com/android/launcher3/util/ViewCache.java

@@ -21,6 +21,8 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.annotation.VisibleForTesting;
+
 import com.android.launcher3.R;
 
 /**
@@ -67,7 +69,8 @@ public class ViewCache {
         }
     }
 
-    private static class CacheEntry {
+    @VisibleForTesting
+    static class CacheEntry {
 
         final int mMaxSize;
         final View[] mViews;

tests/src/com/android/launcher3/util/ViewCacheTest.kt

@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.launcher3.util
+
+import android.view.View
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
+import com.android.launcher3.R
+import com.android.launcher3.util.ViewCache.CacheEntry
+import com.google.common.truth.Truth.assertThat
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class ViewCacheTest {
+
+    private lateinit var underTest: ViewCache
+
+    private val context = InstrumentationRegistry.getInstrumentation().context
+    private val layoutId =
+        context.run { resources.getIdentifier("test_layout_appwidget_blue", "layout", packageName) }
+
+    @Before
+    fun setUp() {
+        underTest = ViewCache()
+        underTest.setCacheSize(layoutId, 5)
+    }
+
+    @Test
+    fun get_view_from_empty_cache() {
+        val view: View = underTest.getView(layoutId, context, null)
+
+        val cacheEntry = view.getTag(R.id.cache_entry_tag_id) as ViewCache.CacheEntry
+        assertThat(cacheEntry).isNotNull()
+        assertThat(cacheEntry.mMaxSize).isEqualTo(5)
+        assertThat(cacheEntry.mCurrentSize).isEqualTo(0)
+        assertThat(cacheEntry.mViews[0]).isNull()
+    }
+
+    @Test
+    fun recyclerView() {
+        val view: View = underTest.getView(layoutId, context, null)
+        val cacheEntry = view.getTag(R.id.cache_entry_tag_id) as ViewCache.CacheEntry
+
+        underTest.recycleView(layoutId, view)
+
+        assertThat(cacheEntry.mMaxSize).isEqualTo(5)
+        assertThat(cacheEntry.mCurrentSize).isEqualTo(1)
+        assertThat(cacheEntry.mViews[0]).isSameInstanceAs(view)
+    }
+
+    @Test
+    fun get_view_from_cache() {
+        val view: View = underTest.getView(layoutId, context, null)
+        underTest.recycleView(layoutId, view)
+
+        val newView = underTest.getView<View>(layoutId, context, null)
+
+        assertThat(view).isSameInstanceAs(newView)
+    }
+
+    @Test
+    fun change_tag_id_recyclerView_noOp() {
+        val view: View = underTest.getView(layoutId, context, null)
+        val cacheEntry = view.getTag(R.id.cache_entry_tag_id) as ViewCache.CacheEntry
+
+        view.setTag(R.id.cache_entry_tag_id, CacheEntry(3))
+        underTest.recycleView(layoutId, view)
+
+        assertThat(cacheEntry.mMaxSize).isEqualTo(5)
+        assertThat(cacheEntry.mCurrentSize).isEqualTo(0)
+        assertThat(cacheEntry.mViews[0]).isNull()
+    }
+}