[fenix] For https://github.com/mozilla-mobile/fenix/issues/4776: Added Unit tests for About Page.

app/src/main/java/org/mozilla/fenix/settings/about/AboutPageAdapter.kt

@@ -6,12 +6,14 @@ package org.mozilla.fenix.settings.about
 
 import android.view.LayoutInflater
 import android.view.ViewGroup
+import androidx.annotation.VisibleForTesting
 import androidx.recyclerview.widget.RecyclerView
 import org.mozilla.fenix.settings.about.viewholders.AboutItemViewHolder
 
 class AboutPageAdapter(private val listener: AboutPageListener) : RecyclerView.Adapter<AboutItemViewHolder>() {
 
-    private var aboutList: List<AboutPageItem>? = null
+    @VisibleForTesting
+    var aboutList: List<AboutPageItem>? = null
 
     fun updateData(items: List<AboutPageItem>) {
         this.aboutList = items

app/src/test/java/org/mozilla/fenix/settings/about/AboutPageAdapterTest.kt

@@ -0,0 +1,101 @@
+/* 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.settings.about
+
+import android.view.ViewGroup
+import android.widget.TextView
+import assertk.assertThat
+import assertk.assertions.isEqualTo
+import io.mockk.Runs
+import io.mockk.every
+import io.mockk.just
+import io.mockk.mockk
+import io.mockk.spyk
+import io.mockk.verify
+import kotlinx.android.synthetic.main.about_list_item.view.*
+import mozilla.components.support.test.robolectric.testContext
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mozilla.fenix.TestApplication
+import org.mozilla.fenix.settings.about.viewholders.AboutItemViewHolder
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+@RunWith(RobolectricTestRunner::class)
+@Config(application = TestApplication::class)
+class AboutPageAdapterTest {
+    private var aboutList: List<AboutPageItem> =
+        mutableListOf(
+            AboutPageItem.Item(
+                AboutItem.ExternalLink(
+                    AboutItemType.WHATS_NEW,
+                    "https://mozilla.org"
+                ), "Libraries"
+            ),
+            AboutPageItem.Item(AboutItem.Libraries, "Libraries")
+        )
+    private val listener: AboutPageListener = mockk(relaxed = true)
+
+    @Test
+    fun `updateData should set the new data and call notifyDataSetChanged()`() {
+        val adapter = spyk(AboutPageAdapter(listener), recordPrivateCalls = true)
+        every { adapter.notifyDataSetChanged() } just Runs
+
+        adapter.updateData(aboutList)
+
+        // Wasn't able to test in verify block the 'adapter.aboutList' setter from the updateData method
+        assertThat(adapter.aboutList).isEqualTo(aboutList)
+        verify {
+            adapter.notifyDataSetChanged()
+        }
+    }
+
+    @Test
+    fun `getItemCount on a default instantiated Adapter should return 0`() {
+        val adapter = AboutPageAdapter(listener)
+
+        assertThat(adapter.itemCount).isEqualTo(0)
+    }
+
+    @Test
+    fun `getItemCount after updateData() call should return the correct list size`() {
+        val adapter = AboutPageAdapter(listener)
+
+        adapter.updateData(aboutList)
+
+        assertThat(adapter.itemCount).isEqualTo(2)
+    }
+
+    @Test
+    fun `the adapter uses AboutItemViewHolder`() {
+        val adapter = AboutPageAdapter(listener)
+        val parentView: ViewGroup = mockk(relaxed = true)
+        every { parentView.context } returns testContext
+
+        val viewHolder = adapter.onCreateViewHolder(parentView, AboutItemViewHolder.LAYOUT_ID)
+
+        assertThat(viewHolder::class).isEqualTo(AboutItemViewHolder::class)
+    }
+
+    @Test
+    fun `the adapter binds the right item to a ViewHolder`() {
+        val adapter = AboutPageAdapter(listener)
+        val parentView: ViewGroup = mockk(relaxed = true)
+        every { parentView.about_item_title } returns TextView(testContext)
+        val viewHolder = spyk(AboutItemViewHolder(parentView, mockk()))
+        every {
+            adapter.onCreateViewHolder(
+                parentView,
+                AboutItemViewHolder.LAYOUT_ID
+            )
+        } returns viewHolder
+        every { viewHolder.bind(any()) } just Runs
+
+        adapter.updateData(aboutList)
+        adapter.bindViewHolder(viewHolder, 1)
+
+        verify { viewHolder.bind(adapter.aboutList?.get(1) as AboutPageItem.Item) }
+    }
+}