Adding upstream version 126.0.upstream/126.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

35 files changed, 3286 insertions, 0 deletions

diff --git a/mobile/android/android-components/components/feature/top-sites/README.md b/mobile/android/android-components/components/feature/top-sites/README.md
new file mode 100644
index 0000000000..43da2f004b
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/README.md
@@ -0,0 +1,19 @@
+# [Android Components](../../../README.md) > Feature > Top Sites
+
+Feature implementation for saving and removing top sites.
+
+## Usage
+
+### Setting up the dependency
+
+Use Gradle to download the library from [maven.mozilla.org](https://maven.mozilla.org/) ([Setup repository](../../../README.md#maven-repository)):
+
+```Groovy
+implementation "org.mozilla.components:feature-top-sites:{latest-version}"
+```
+
+## License
+
+    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/
diff --git a/mobile/android/android-components/components/feature/top-sites/build.gradle b/mobile/android/android-components/components/feature/top-sites/build.gradle
new file mode 100644
index 0000000000..2361376051
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/build.gradle
@@ -0,0 +1,82 @@
+/* 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/. */
+
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
+apply plugin: 'com.google.devtools.ksp'
+
+android {
+    defaultConfig {
+        minSdkVersion config.minSdkVersion
+        compileSdk config.compileSdkVersion
+        targetSdkVersion config.targetSdkVersion
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+
+        ksp {
+            arg("room.schemaLocation", "$projectDir/schemas".toString())
+            arg("room.generateKotlin", "true")
+        }
+
+        javaCompileOptions {
+            annotationProcessorOptions {
+                arguments += ["room.incremental": "true"]
+            }
+        }
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+
+    packagingOptions {
+        exclude 'META-INF/proguard/androidx-annotations.pro'
+    }
+
+    sourceSets {
+        androidTest.assets.srcDirs += files("$projectDir/schemas".toString())
+    }
+
+    namespace 'mozilla.components.feature.top.sites'
+}
+
+dependencies {
+    implementation project(':browser-storage-sync')
+    implementation project(':concept-toolbar')
+    implementation project(':support-ktx')
+    implementation project(':support-base')
+    implementation project(':support-utils')
+
+    implementation ComponentsDependencies.kotlin_coroutines
+
+    implementation ComponentsDependencies.androidx_paging
+    implementation ComponentsDependencies.androidx_lifecycle_livedata
+
+    implementation ComponentsDependencies.androidx_room_runtime
+    ksp ComponentsDependencies.androidx_room_compiler
+
+    testImplementation project(':support-test')
+
+    testImplementation ComponentsDependencies.androidx_test_core
+    testImplementation ComponentsDependencies.androidx_test_junit
+    testImplementation ComponentsDependencies.testing_junit
+    testImplementation ComponentsDependencies.testing_coroutines
+    testImplementation ComponentsDependencies.testing_robolectric
+    testImplementation ComponentsDependencies.kotlin_coroutines
+
+    androidTestImplementation project(':support-android-test')
+
+    androidTestImplementation ComponentsDependencies.androidx_room_testing
+    androidTestImplementation ComponentsDependencies.androidx_arch_core_testing
+    androidTestImplementation ComponentsDependencies.androidx_test_core
+    androidTestImplementation ComponentsDependencies.androidx_test_runner
+    androidTestImplementation ComponentsDependencies.androidx_test_rules
+    androidTestImplementation ComponentsDependencies.testing_coroutines
+}
+
+apply from: '../../../android-lint.gradle'
+apply from: '../../../publish.gradle'
+ext.configurePublish(config.componentsGroupId, archivesBaseName, project.ext.description)
diff --git a/mobile/android/android-components/components/feature/top-sites/proguard-rules.pro b/mobile/android/android-components/components/feature/top-sites/proguard-rules.pro
new file mode 100644
index 0000000000..f1b424510d
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/proguard-rules.pro
@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
diff --git a/mobile/android/android-components/components/feature/top-sites/schemas/mozilla.components.feature.top.sites.db.TopSiteDatabase/1.json b/mobile/android/android-components/components/feature/top-sites/schemas/mozilla.components.feature.top.sites.db.TopSiteDatabase/1.json
new file mode 100644
index 0000000000..5cf0219da6
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/schemas/mozilla.components.feature.top.sites.db.TopSiteDatabase/1.json
@@ -0,0 +1,52 @@
+{
+  "formatVersion": 1,
+  "database": {
+    "version": 1,
+    "identityHash": "ce733d9c47cd10312a1c13de8efb7e8d",
+    "entities": [
+      {
+        "tableName": "top_sites",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `title` TEXT NOT NULL, `url` TEXT NOT NULL, `created_at` INTEGER NOT NULL)",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER",
+            "notNull": false
+          },
+          {
+            "fieldPath": "title",
+            "columnName": "title",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "url",
+            "columnName": "url",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "createdAt",
+            "columnName": "created_at",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "columnNames": [
+            "id"
+          ],
+          "autoGenerate": true
+        },
+        "indices": [],
+        "foreignKeys": []
+      }
+    ],
+    "views": [],
+    "setupQueries": [
+      "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, 'ce733d9c47cd10312a1c13de8efb7e8d')"
+    ]
+  }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/schemas/mozilla.components.feature.top.sites.db.TopSiteDatabase/2.json b/mobile/android/android-components/components/feature/top-sites/schemas/mozilla.components.feature.top.sites.db.TopSiteDatabase/2.json
new file mode 100644
index 0000000000..8bc2effe6e
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/schemas/mozilla.components.feature.top.sites.db.TopSiteDatabase/2.json
@@ -0,0 +1,58 @@
+{
+  "formatVersion": 1,
+  "database": {
+    "version": 2,
+    "identityHash": "4c6cae8272b2580de8cb444de31f27d5",
+    "entities": [
+      {
+        "tableName": "top_sites",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `title` TEXT NOT NULL, `url` TEXT NOT NULL, `is_default` INTEGER NOT NULL, `created_at` INTEGER NOT NULL)",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER",
+            "notNull": false
+          },
+          {
+            "fieldPath": "title",
+            "columnName": "title",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "url",
+            "columnName": "url",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "isDefault",
+            "columnName": "is_default",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "createdAt",
+            "columnName": "created_at",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "columnNames": [
+            "id"
+          ],
+          "autoGenerate": true
+        },
+        "indices": [],
+        "foreignKeys": []
+      }
+    ],
+    "views": [],
+    "setupQueries": [
+      "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '4c6cae8272b2580de8cb444de31f27d5')"
+    ]
+  }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/schemas/mozilla.components.feature.top.sites.db.TopSiteDatabase/3.json b/mobile/android/android-components/components/feature/top-sites/schemas/mozilla.components.feature.top.sites.db.TopSiteDatabase/3.json
new file mode 100644
index 0000000000..e7b4ad010e
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/schemas/mozilla.components.feature.top.sites.db.TopSiteDatabase/3.json
@@ -0,0 +1,58 @@
+{
+  "formatVersion": 1,
+  "database": {
+    "version": 3,
+    "identityHash": "4c6cae8272b2580de8cb444de31f27d5",
+    "entities": [
+      {
+        "tableName": "top_sites",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER PRIMARY KEY AUTOINCREMENT, `title` TEXT NOT NULL, `url` TEXT NOT NULL, `is_default` INTEGER NOT NULL, `created_at` INTEGER NOT NULL)",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER",
+            "notNull": false
+          },
+          {
+            "fieldPath": "title",
+            "columnName": "title",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "url",
+            "columnName": "url",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "isDefault",
+            "columnName": "is_default",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "createdAt",
+            "columnName": "created_at",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "columnNames": [
+            "id"
+          ],
+          "autoGenerate": true
+        },
+        "indices": [],
+        "foreignKeys": []
+      }
+    ],
+    "views": [],
+    "setupQueries": [
+      "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '4c6cae8272b2580de8cb444de31f27d5')"
+    ]
+  }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/androidTest/java/mozilla/components/feature/top/sites/OnDevicePinnedSitesStorageTest.kt b/mobile/android/android-components/components/feature/top-sites/src/androidTest/java/mozilla/components/feature/top/sites/OnDevicePinnedSitesStorageTest.kt
new file mode 100644
index 0000000000..ac5563190d
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/androidTest/java/mozilla/components/feature/top/sites/OnDevicePinnedSitesStorageTest.kt
@@ -0,0 +1,313 @@
+/* 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 mozilla.components.feature.top.sites
+
+import android.content.Context
+import androidx.arch.core.executor.testing.InstantTaskExecutorRule
+import androidx.room.Room
+import androidx.room.testing.MigrationTestHelper
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.platform.app.InstrumentationRegistry
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.runTest
+import mozilla.components.feature.top.sites.db.Migrations
+import mozilla.components.feature.top.sites.db.TopSiteDatabase
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Executors
+
+private const val MIGRATION_TEST_DB = "migration-test"
+
+@ExperimentalCoroutinesApi // for runTest
+@Suppress("LargeClass")
+class OnDevicePinnedSitesStorageTest {
+    private lateinit var context: Context
+    private lateinit var storage: PinnedSiteStorage
+    private lateinit var executor: ExecutorService
+
+    @get:Rule
+    var instantTaskExecutorRule = InstantTaskExecutorRule()
+
+    @get:Rule
+    val helper: MigrationTestHelper = MigrationTestHelper(
+        InstrumentationRegistry.getInstrumentation(),
+        TopSiteDatabase::class.java,
+    )
+
+    @Before
+    fun setUp() {
+        executor = Executors.newSingleThreadExecutor()
+
+        context = ApplicationProvider.getApplicationContext()
+        val database = Room.inMemoryDatabaseBuilder(context, TopSiteDatabase::class.java).build()
+
+        storage = PinnedSiteStorage(context)
+        storage.database = lazy { database }
+    }
+
+    @After
+    fun tearDown() {
+        executor.shutdown()
+    }
+
+    @Test
+    fun testAddingAllDefaultSites() = runTest {
+        val defaultTopSites = listOf(
+            Pair("Mozilla", "https://www.mozilla.org"),
+            Pair("Firefox", "https://www.firefox.com"),
+            Pair("Wikipedia", "https://www.wikipedia.com"),
+            Pair("Pocket", "https://www.getpocket.com"),
+        )
+
+        storage.addAllPinnedSites(defaultTopSites, isDefault = true)
+
+        val topSites = storage.getPinnedSites()
+
+        assertEquals(4, topSites.size)
+        assertEquals(4, storage.getPinnedSitesCount())
+
+        assertEquals("Mozilla", topSites[0].title)
+        assertEquals("https://www.mozilla.org", topSites[0].url)
+        assertTrue(topSites[0] is TopSite.Default)
+        assertEquals("Firefox", topSites[1].title)
+        assertEquals("https://www.firefox.com", topSites[1].url)
+        assertTrue(topSites[1] is TopSite.Default)
+        assertEquals("Wikipedia", topSites[2].title)
+        assertEquals("https://www.wikipedia.com", topSites[2].url)
+        assertTrue(topSites[2] is TopSite.Default)
+        assertEquals("Pocket", topSites[3].title)
+        assertEquals("https://www.getpocket.com", topSites[3].url)
+        assertTrue(topSites[3] is TopSite.Default)
+    }
+
+    @Test
+    fun testAddingPinnedSite() = runTest {
+        storage.addPinnedSite("Mozilla", "https://www.mozilla.org")
+        storage.addPinnedSite("Firefox", "https://www.firefox.com", isDefault = true)
+
+        val topSites = storage.getPinnedSites()
+
+        assertEquals(2, topSites.size)
+        assertEquals(2, storage.getPinnedSitesCount())
+
+        assertEquals("Mozilla", topSites[0].title)
+        assertEquals("https://www.mozilla.org", topSites[0].url)
+        assertTrue(topSites[0] is TopSite.Pinned)
+        assertEquals("Firefox", topSites[1].title)
+        assertEquals("https://www.firefox.com", topSites[1].url)
+        assertTrue(topSites[1] is TopSite.Default)
+    }
+
+    @Test
+    fun testRemovingPinnedSites() = runTest {
+        storage.addPinnedSite("Mozilla", "https://www.mozilla.org")
+        storage.addPinnedSite("Firefox", "https://www.firefox.com")
+
+        storage.getPinnedSites().let { topSites ->
+            assertEquals(2, topSites.size)
+            assertEquals(2, storage.getPinnedSitesCount())
+
+            storage.removePinnedSite(topSites[0])
+        }
+
+        storage.getPinnedSites().let { topSites ->
+            assertEquals(1, topSites.size)
+            assertEquals(1, storage.getPinnedSitesCount())
+
+            assertEquals("Firefox", topSites[0].title)
+            assertEquals("https://www.firefox.com", topSites[0].url)
+        }
+    }
+
+    @Test
+    fun testGettingPinnedSites() = runTest {
+        storage.addPinnedSite("Mozilla", "https://www.mozilla.org")
+        storage.addPinnedSite("Firefox", "https://www.firefox.com", isDefault = true)
+
+        val topSites = storage.getPinnedSites()
+
+        assertNotNull(topSites)
+        assertEquals(2, topSites.size)
+        assertEquals(2, storage.getPinnedSitesCount())
+
+        with(topSites[0]) {
+            assertEquals("Mozilla", title)
+            assertEquals("https://www.mozilla.org", url)
+            assertTrue(this is TopSite.Pinned)
+        }
+
+        with(topSites[1]) {
+            assertEquals("Firefox", title)
+            assertEquals("https://www.firefox.com", url)
+            assertTrue(this is TopSite.Default)
+        }
+    }
+
+    @Test
+    fun testUpdatingPinnedSites() = runTest {
+        storage.addPinnedSite("Mozilla", "https://www.mozilla.org")
+        var pinnedSites = storage.getPinnedSites()
+
+        assertEquals(1, pinnedSites.size)
+        assertEquals(1, storage.getPinnedSitesCount())
+        assertEquals("https://www.mozilla.org", pinnedSites[0].url)
+        assertEquals("Mozilla", pinnedSites[0].title)
+
+        storage.updatePinnedSite(pinnedSites[0], "", "")
+
+        pinnedSites = storage.getPinnedSites()
+        assertEquals(1, pinnedSites.size)
+        assertEquals(1, storage.getPinnedSitesCount())
+        assertEquals("", pinnedSites[0].url)
+        assertEquals("", pinnedSites[0].title)
+
+        storage.updatePinnedSite(pinnedSites[0], "Mozilla Firefox", "https://www.firefox.com")
+
+        pinnedSites = storage.getPinnedSites()
+        assertEquals(1, pinnedSites.size)
+        assertEquals(1, storage.getPinnedSitesCount())
+        assertEquals("https://www.firefox.com", pinnedSites[0].url)
+        assertEquals("Mozilla Firefox", pinnedSites[0].title)
+    }
+
+    @Test
+    fun migrate1to2() {
+        val dbVersion1 = helper.createDatabase(MIGRATION_TEST_DB, 1).apply {
+            execSQL(
+                "INSERT INTO " +
+                    "top_sites " +
+                    "(title, url, created_at) " +
+                    "VALUES " +
+                    "('Mozilla','mozilla.org',1)," +
+                    "('Top Articles','https://getpocket.com/fenix-top-articles',2)," +
+                    "('Wikipedia','https://www.wikipedia.org/',3)," +
+                    "('YouTube','https://www.youtube.com/',4)",
+            )
+        }
+
+        dbVersion1.query("SELECT * FROM top_sites").use { cursor ->
+            assertEquals(4, cursor.columnCount)
+        }
+
+        val dbVersion2 = helper.runMigrationsAndValidate(
+            MIGRATION_TEST_DB,
+            2,
+            true,
+            Migrations.migration_1_2,
+        ).apply {
+            execSQL(
+                "INSERT INTO " +
+                    "top_sites " +
+                    "(title, url, is_default, created_at) " +
+                    "VALUES " +
+                    "('Firefox','firefox.com',1,5)," +
+                    "('Monitor','https://monitor.firefox.com/',0,5)",
+            )
+        }
+
+        dbVersion2.query("SELECT * FROM top_sites").use { cursor ->
+            assertEquals(5, cursor.columnCount)
+
+            // Check is_default for Mozilla
+            cursor.moveToFirst()
+            assertEquals(0, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+
+            // Check is_default for Top Articles
+            cursor.moveToNext()
+            assertEquals(1, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+
+            // Check is_default for Wikipedia
+            cursor.moveToNext()
+            assertEquals(1, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+
+            // Check is_default for YouTube
+            cursor.moveToNext()
+            assertEquals(1, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+
+            // Check is_default for Firefox
+            cursor.moveToNext()
+            assertEquals(1, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+
+            // Check is_default for Monitor
+            cursor.moveToNext()
+            assertEquals(0, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+        }
+    }
+
+    @Test
+    fun migrate2to3() {
+        val dbVersion2 = helper.createDatabase(MIGRATION_TEST_DB, 2).apply {
+            execSQL(
+                "INSERT INTO " +
+                    "top_sites " +
+                    "(title, url, is_default, created_at) " +
+                    "VALUES " +
+                    "('Mozilla','mozilla.org',0,1)," +
+                    "('Top Articles','https://getpocket.com/fenix-top-articles',0,2)," +
+                    "('Wikipedia','https://www.wikipedia.org/',0,3)," +
+                    "('YouTube','https://www.youtube.com/',0,4)",
+            )
+        }
+
+        dbVersion2.query("SELECT * FROM top_sites").use { cursor ->
+            assertEquals(5, cursor.columnCount)
+        }
+
+        val dbVersion3 = helper.runMigrationsAndValidate(
+            MIGRATION_TEST_DB,
+            3,
+            true,
+            Migrations.migration_2_3,
+        )
+
+        dbVersion3.query("SELECT * FROM top_sites").use { cursor ->
+            assertEquals(5, cursor.columnCount)
+            assertEquals(4, cursor.count)
+
+            // Check isDefault for Mozilla
+            cursor.moveToFirst()
+            assertEquals("Mozilla", cursor.getString(cursor.getColumnIndexOrThrow("title")))
+            assertEquals("mozilla.org", cursor.getString(cursor.getColumnIndexOrThrow("url")))
+            assertEquals(0, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+            assertEquals(1, cursor.getInt(cursor.getColumnIndexOrThrow("created_at")))
+
+            // Check isDefault for Top Articles
+            cursor.moveToNext()
+            assertEquals("Top Articles", cursor.getString(cursor.getColumnIndexOrThrow("title")))
+            assertEquals(
+                "https://getpocket.com/fenix-top-articles",
+                cursor.getString(cursor.getColumnIndexOrThrow("url")),
+            )
+            assertEquals(1, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+            assertEquals(2, cursor.getInt(cursor.getColumnIndexOrThrow("created_at")))
+
+            // Check isDefault for Wikipedia
+            cursor.moveToNext()
+            assertEquals("Wikipedia", cursor.getString(cursor.getColumnIndexOrThrow("title")))
+            assertEquals(
+                "https://www.wikipedia.org/",
+                cursor.getString(cursor.getColumnIndexOrThrow("url")),
+            )
+            assertEquals(1, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+            assertEquals(3, cursor.getInt(cursor.getColumnIndexOrThrow("created_at")))
+
+            // Check isDefault for YouTube
+            cursor.moveToNext()
+            assertEquals("YouTube", cursor.getString(cursor.getColumnIndexOrThrow("title")))
+            assertEquals(
+                "https://www.youtube.com/",
+                cursor.getString(cursor.getColumnIndexOrThrow("url")),
+            )
+            assertEquals(1, cursor.getInt(cursor.getColumnIndexOrThrow("is_default")))
+            assertEquals(4, cursor.getInt(cursor.getColumnIndexOrThrow("created_at")))
+        }
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/androidTest/java/mozilla/components/feature/top/sites/db/PinnedSiteDaoTest.kt b/mobile/android/android-components/components/feature/top-sites/src/androidTest/java/mozilla/components/feature/top/sites/db/PinnedSiteDaoTest.kt
new file mode 100644
index 0000000000..ca146dee82
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/androidTest/java/mozilla/components/feature/top/sites/db/PinnedSiteDaoTest.kt
@@ -0,0 +1,118 @@
+/* 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 mozilla.components.feature.top.sites.db
+
+import android.content.Context
+import androidx.arch.core.executor.testing.InstantTaskExecutorRule
+import androidx.room.Room
+import androidx.test.core.app.ApplicationProvider
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Executors
+
+class PinnedSiteDaoTest {
+    private val context: Context
+        get() = ApplicationProvider.getApplicationContext()
+
+    private lateinit var database: TopSiteDatabase
+    private lateinit var pinnedSiteDao: PinnedSiteDao
+    private lateinit var executor: ExecutorService
+
+    @get:Rule
+    var instantTaskExecutorRule = InstantTaskExecutorRule()
+
+    @Before
+    fun setUp() {
+        database = Room.inMemoryDatabaseBuilder(context, TopSiteDatabase::class.java).build()
+        pinnedSiteDao = database.pinnedSiteDao()
+        executor = Executors.newSingleThreadExecutor()
+    }
+
+    @After
+    fun tearDown() {
+        database.close()
+        executor.shutdown()
+    }
+
+    @Test
+    fun testAddingTopSite() {
+        val topSite = PinnedSiteEntity(
+            title = "Mozilla",
+            url = "https://www.mozilla.org",
+            isDefault = false,
+            createdAt = 200,
+        ).also {
+            it.id = pinnedSiteDao.insertPinnedSite(it)
+        }
+
+        val pinnedSites = pinnedSiteDao.getPinnedSites()
+
+        assertEquals(1, pinnedSites.size)
+        assertEquals(1, pinnedSiteDao.getPinnedSitesCount())
+        assertEquals(topSite, pinnedSites[0])
+    }
+
+    @Test
+    fun testUpdatingTopSite() {
+        val topSite = PinnedSiteEntity(
+            title = "Mozilla",
+            url = "https://www.mozilla.org",
+            isDefault = false,
+            createdAt = 200,
+        ).also {
+            it.id = pinnedSiteDao.insertPinnedSite(it)
+        }
+
+        topSite.title = "Mozilla (IT)"
+        topSite.url = "https://www.mozilla.org/it"
+        pinnedSiteDao.updatePinnedSite(topSite)
+
+        val pinnedSites = pinnedSiteDao.getPinnedSites()
+
+        assertEquals(1, pinnedSites.size)
+        assertEquals(1, pinnedSiteDao.getPinnedSitesCount())
+        assertEquals(topSite, pinnedSites[0])
+        assertEquals(topSite.title, pinnedSites[0].title)
+        assertEquals(topSite.url, pinnedSites[0].url)
+    }
+
+    @Test
+    fun testRemovingTopSite() {
+        val topSite1 = PinnedSiteEntity(
+            title = "Mozilla",
+            url = "https://www.mozilla.org",
+            isDefault = false,
+            createdAt = 200,
+        ).also {
+            it.id = pinnedSiteDao.insertPinnedSite(it)
+        }
+
+        val topSite2 = PinnedSiteEntity(
+            title = "Firefox",
+            url = "https://www.firefox.com",
+            isDefault = false,
+            createdAt = 100,
+        ).also {
+            it.id = pinnedSiteDao.insertPinnedSite(it)
+        }
+
+        var pinnedSites = pinnedSiteDao.getPinnedSites()
+
+        assertEquals(2, pinnedSites.size)
+        assertEquals(2, pinnedSiteDao.getPinnedSitesCount())
+
+        pinnedSiteDao.deletePinnedSite(topSite1)
+
+        pinnedSites = pinnedSiteDao.getPinnedSites()
+
+        assertEquals(1, pinnedSites.size)
+        assertEquals(1, pinnedSiteDao.getPinnedSitesCount())
+        assertEquals(topSite2, pinnedSites[0])
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/AndroidManifest.xml b/mobile/android/android-components/components/feature/top-sites/src/main/AndroidManifest.xml
new file mode 100644
index 0000000000..e16cda1d34
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/AndroidManifest.xml
@@ -0,0 +1,4 @@
+<!-- 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/. -->
+<manifest />
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/DefaultTopSitesStorage.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/DefaultTopSitesStorage.kt
new file mode 100644
index 0000000000..960215abef
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/DefaultTopSitesStorage.kt
@@ -0,0 +1,140 @@
+/* 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 mozilla.components.feature.top.sites
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import mozilla.components.browser.storage.sync.PlacesHistoryStorage
+import mozilla.components.feature.top.sites.ext.hasHost
+import mozilla.components.feature.top.sites.ext.hasUrl
+import mozilla.components.feature.top.sites.ext.toTopSite
+import mozilla.components.feature.top.sites.facts.emitTopSitesCountFact
+import mozilla.components.support.base.log.logger.Logger
+import mozilla.components.support.base.observer.Observable
+import mozilla.components.support.base.observer.ObserverRegistry
+import kotlin.coroutines.CoroutineContext
+
+/**
+ * Default implementation of [TopSitesStorage].
+ *
+ * @param pinnedSitesStorage An instance of [PinnedSiteStorage], used for storing pinned sites.
+ * @param historyStorage An instance of [PlacesHistoryStorage], used for retrieving top frecent
+ * sites from history.
+ * @param topSitesProvider An optional instance of [TopSitesProvider], used for retrieving
+ * additional top sites from a provider. The returned top sites are added before pinned sites.
+ * @param defaultTopSites A list containing a title to url pair of default top sites to be added
+ * to the [PinnedSiteStorage].
+ */
+class DefaultTopSitesStorage(
+    private val pinnedSitesStorage: PinnedSiteStorage,
+    private val historyStorage: PlacesHistoryStorage,
+    private val topSitesProvider: TopSitesProvider? = null,
+    private val defaultTopSites: List<Pair<String, String>> = listOf(),
+    coroutineContext: CoroutineContext = Dispatchers.IO,
+) : TopSitesStorage, Observable<TopSitesStorage.Observer> by ObserverRegistry() {
+
+    private var scope = CoroutineScope(coroutineContext)
+    private val logger = Logger("DefaultTopSitesStorage")
+
+    // Cache of the last retrieved top sites
+    var cachedTopSites = listOf<TopSite>()
+
+    init {
+        if (defaultTopSites.isNotEmpty()) {
+            scope.launch {
+                pinnedSitesStorage.addAllPinnedSites(defaultTopSites, isDefault = true)
+            }
+        }
+    }
+
+    override fun addTopSite(title: String, url: String, isDefault: Boolean) {
+        scope.launch {
+            pinnedSitesStorage.addPinnedSite(title, url, isDefault)
+            notifyObservers { onStorageUpdated() }
+        }
+    }
+
+    override fun removeTopSite(topSite: TopSite) {
+        scope.launch {
+            if (topSite is TopSite.Default || topSite is TopSite.Pinned) {
+                pinnedSitesStorage.removePinnedSite(topSite)
+            }
+
+            // Remove the top site from both history and pinned sites storage to avoid having it
+            // show up as a frecent site if it is a pinned site.
+            if (topSite !is TopSite.Provided) {
+                historyStorage.deleteVisitsFor(topSite.url)
+            }
+
+            notifyObservers { onStorageUpdated() }
+        }
+    }
+
+    override fun updateTopSite(topSite: TopSite, title: String, url: String) {
+        scope.launch {
+            if (topSite is TopSite.Default || topSite is TopSite.Pinned) {
+                pinnedSitesStorage.updatePinnedSite(topSite, title, url)
+            }
+
+            notifyObservers { onStorageUpdated() }
+        }
+    }
+
+    @Suppress("ComplexCondition", "TooGenericExceptionCaught")
+    override suspend fun getTopSites(
+        totalSites: Int,
+        frecencyConfig: TopSitesFrecencyConfig?,
+        providerConfig: TopSitesProviderConfig?,
+    ): List<TopSite> {
+        val topSites = ArrayList<TopSite>()
+        val pinnedSites = pinnedSitesStorage.getPinnedSites().take(totalSites)
+        var providerTopSites = emptyList<TopSite>()
+        var numSitesRequired = totalSites - pinnedSites.size
+
+        if (topSitesProvider != null &&
+            providerConfig != null &&
+            providerConfig.showProviderTopSites &&
+            pinnedSites.size < providerConfig.maxThreshold
+        ) {
+            try {
+                providerTopSites = topSitesProvider
+                    .getTopSites(allowCache = true)
+                    .filter { providerConfig.providerFilter?.invoke(it) ?: true }
+                    .take(numSitesRequired)
+                    .take(providerConfig.maxThreshold - pinnedSites.size)
+                topSites.addAll(providerTopSites)
+                numSitesRequired -= providerTopSites.size
+            } catch (e: Exception) {
+                logger.error("Failed to fetch top sites from provider", e)
+            }
+        }
+
+        topSites.addAll(pinnedSites)
+
+        if (frecencyConfig?.frecencyTresholdOption != null && numSitesRequired > 0) {
+            // Get 'totalSites' sites for duplicate entries with
+            // existing pinned sites
+            val frecentSites = historyStorage
+                .getTopFrecentSites(totalSites, frecencyConfig.frecencyTresholdOption)
+                .map { it.toTopSite() }
+                .filter {
+                    !pinnedSites.hasUrl(it.url) &&
+                        !providerTopSites.hasHost(it.url) &&
+                        frecencyConfig.frecencyFilter?.invoke(it) ?: true
+                }
+                .take(numSitesRequired)
+
+            topSites.addAll(frecentSites)
+        }
+
+        if (topSites != cachedTopSites) {
+            emitTopSitesCountFact(pinnedSites.size)
+            cachedTopSites = topSites
+        }
+
+        return topSites
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/PinnedSiteStorage.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/PinnedSiteStorage.kt
new file mode 100644
index 0000000000..d77a599ace
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/PinnedSiteStorage.kt
@@ -0,0 +1,104 @@
+/* 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 mozilla.components.feature.top.sites
+
+import android.content.Context
+import androidx.annotation.VisibleForTesting
+import kotlinx.coroutines.Dispatchers.IO
+import kotlinx.coroutines.withContext
+import mozilla.components.feature.top.sites.db.PinnedSiteEntity
+import mozilla.components.feature.top.sites.db.TopSiteDatabase
+import mozilla.components.feature.top.sites.db.toPinnedSite
+
+/**
+ * A storage implementation for organizing pinned sites.
+ */
+class PinnedSiteStorage(context: Context) {
+
+    @VisibleForTesting
+    internal var currentTimeMillis: () -> Long = { System.currentTimeMillis() }
+
+    @VisibleForTesting
+    internal var database: Lazy<TopSiteDatabase> = lazy { TopSiteDatabase.get(context) }
+    private val pinnedSiteDao by lazy { database.value.pinnedSiteDao() }
+
+    /**
+     * Adds the given list pinned sites.
+     *
+     * @param topSites A list containing a title to url pair of top sites to be added.
+     * @param isDefault Whether or not the pinned site added should be a default pinned site. This
+     * is used to identify pinned sites that are added by the application.
+     */
+    suspend fun addAllPinnedSites(
+        topSites: List<Pair<String, String>>,
+        isDefault: Boolean = false,
+    ) = withContext(IO) {
+        val siteEntities = topSites.map { (title, url) ->
+            PinnedSiteEntity(
+                title = title,
+                url = url,
+                isDefault = isDefault,
+                createdAt = currentTimeMillis(),
+            )
+        }
+        pinnedSiteDao.insertAllPinnedSites(siteEntities)
+    }
+
+    /**
+     * Adds a new pinned site.
+     *
+     * @param title The title string.
+     * @param url The URL string.
+     * @param isDefault Whether or not the pinned site added should be a default pinned site. This
+     * is used to identify pinned sites that are added by the application.
+     */
+    suspend fun addPinnedSite(title: String, url: String, isDefault: Boolean = false) =
+        withContext(IO) {
+            val entity = PinnedSiteEntity(
+                title = title,
+                url = url,
+                isDefault = isDefault,
+                createdAt = currentTimeMillis(),
+            )
+            entity.id = pinnedSiteDao.insertPinnedSite(entity)
+        }
+
+    /**
+     * Returns a list of all the pinned sites.
+     */
+    suspend fun getPinnedSites(): List<TopSite> = withContext(IO) {
+        pinnedSiteDao.getPinnedSites().map { entity -> entity.toTopSite() }
+    }
+
+    /**
+     * Removes the given pinned site.
+     *
+     * @param site The pinned site.
+     */
+    suspend fun removePinnedSite(site: TopSite) = withContext(IO) {
+        pinnedSiteDao.deletePinnedSite(site.toPinnedSite())
+    }
+
+    /**
+     * Updates the given pinned site.
+     *
+     * @param site The pinned site.
+     * @param title The new title for the top site.
+     * @param url The new url for the top site.
+     */
+    suspend fun updatePinnedSite(site: TopSite, title: String, url: String) = withContext(IO) {
+        val pinnedSite = site.toPinnedSite()
+        pinnedSite.title = title
+        pinnedSite.url = url
+        pinnedSiteDao.updatePinnedSite(pinnedSite)
+    }
+
+    /**
+     * Returns a count of pinned sites.
+     */
+    suspend fun getPinnedSitesCount(): Int = withContext(IO) {
+        pinnedSiteDao.getPinnedSitesCount()
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSite.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSite.kt
new file mode 100644
index 0000000000..badc544d8a
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSite.kt
@@ -0,0 +1,90 @@
+/* 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 mozilla.components.feature.top.sites
+
+/**
+ * A top site.
+ */
+sealed class TopSite {
+    abstract val id: Long?
+    abstract val title: String?
+    abstract val url: String
+    abstract val createdAt: Long?
+    abstract val type: String
+
+    /**
+     * This top site was added as a default by the application.
+     *
+     * @property id Unique ID of this top site.
+     * @property title The title of the top site.
+     * @property url The URL of the top site.
+     * @property createdAt The optional date the top site was added.
+     * @property type The type name of the top site.
+     */
+    data class Default(
+        override val id: Long?,
+        override val title: String?,
+        override val url: String,
+        override val createdAt: Long?,
+        override val type: String = "DEFAULT",
+    ) : TopSite()
+
+    /**
+     * This top site was pinned by an user.
+     *
+     * @property id Unique ID of this top site.
+     * @property title The title of the top site.
+     * @property url The URL of the top site.
+     * @property createdAt The optional date the top site was added.
+     * @property type The type name of the top site.
+     */
+    data class Pinned(
+        override val id: Long?,
+        override val title: String?,
+        override val url: String,
+        override val createdAt: Long?,
+        override val type: String = "PINNED",
+    ) : TopSite()
+
+    /**
+     * This top site is auto-generated from the history storage based on the most frecent site.
+     *
+     * @property id Unique ID of this top site.
+     * @property title The title of the top site.
+     * @property url The URL of the top site.
+     * @property createdAt The optional date the top site was added.
+     * @property type The type name of the top site.
+     */
+    data class Frecent(
+        override val id: Long?,
+        override val title: String?,
+        override val url: String,
+        override val createdAt: Long?,
+        override val type: String = "FRECENT",
+    ) : TopSite()
+
+    /**
+     * This top site is provided by the [TopSitesProvider].
+     *
+     * @property id Unique ID of this top site.
+     * @property title The title of the top site.
+     * @property url The URL of the top site.
+     * @property clickUrl The click URL of the top site.
+     * @property imageUrl The image URL of the top site.
+     * @property impressionUrl The URL that needs to be fired when the top site is displayed.
+     * @property createdAt The optional date the top site was added.
+     * @property type The type name of the top site.
+     */
+    data class Provided(
+        override val id: Long?,
+        override val title: String?,
+        override val url: String,
+        val clickUrl: String,
+        val imageUrl: String,
+        val impressionUrl: String,
+        override val createdAt: Long?,
+        override val type: String = "PROVIDED",
+    ) : TopSite()
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesConfig.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesConfig.kt
new file mode 100644
index 0000000000..d9a95bf138
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesConfig.kt
@@ -0,0 +1,50 @@
+/* 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 mozilla.components.feature.top.sites
+
+import mozilla.components.concept.storage.FrecencyThresholdOption
+
+/**
+ * Top sites configuration to specify the number of top sites to display and
+ * whether or not to include top frecent sites in the top sites feature.
+ *
+ * @property totalSites A total number of sites that will be displayed.
+ * @property frecencyConfig An instance of [TopSitesFrecencyConfig] that specifies which top
+ * frecent sites should be included.
+ * @property providerConfig An instance of [TopSitesProviderConfig] that specifies whether or
+ * not to fetch top sites from the [TopSitesProvider].
+ */
+data class TopSitesConfig(
+    val totalSites: Int,
+    val frecencyConfig: TopSitesFrecencyConfig? = null,
+    val providerConfig: TopSitesProviderConfig? = null,
+)
+
+/**
+ * Top sites provider configuration to specify whether or not to fetch top sites from the provider.
+ *
+ * @property showProviderTopSites Whether or not to display the top sites from the provider.
+ * @property maxThreshold Only fetch the top sites from the provider if the number of top sites are
+ * below the maximum threshold.
+ * @property providerFilter Optional function used to filter the top sites from the provider.
+ */
+data class TopSitesProviderConfig(
+    val showProviderTopSites: Boolean,
+    val maxThreshold: Int = Int.MAX_VALUE,
+    val providerFilter: ((TopSite) -> Boolean)? = null,
+)
+
+/**
+ * Top sites frecency configuration used to specify which top frecent sites should be included.
+ *
+ * @property frecencyTresholdOption If [frecencyTresholdOption] is specified, only visited sites with a frecency
+ * score above the given threshold will be returned. Otherwise, frecent top site results are
+ * not included.
+ * @property frecencyFilter Optional function used to filter the top frecent sites.
+ */
+data class TopSitesFrecencyConfig(
+    val frecencyTresholdOption: FrecencyThresholdOption? = null,
+    val frecencyFilter: ((TopSite) -> Boolean)? = null,
+)
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesFeature.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesFeature.kt
new file mode 100644
index 0000000000..412c1e0666
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesFeature.kt
@@ -0,0 +1,38 @@
+/* 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 mozilla.components.feature.top.sites
+
+import mozilla.components.feature.top.sites.presenter.DefaultTopSitesPresenter
+import mozilla.components.feature.top.sites.presenter.TopSitesPresenter
+import mozilla.components.feature.top.sites.view.TopSitesView
+import mozilla.components.support.base.feature.LifecycleAwareFeature
+
+/**
+ * View-bound feature that updates the UI when the [TopSitesStorage] is updated.
+ *
+ * @param view An implementor of [TopSitesView] that will be notified of changes to the storage.
+ * @param storage The top sites storage that stores pinned and frecent sites.
+ * @param config Lambda expression that returns [TopSitesConfig] which species the number of top
+ * sites to return and whether or not to include frequently visited sites.
+ */
+class TopSitesFeature(
+    private val view: TopSitesView,
+    val storage: TopSitesStorage,
+    val config: () -> TopSitesConfig,
+    private val presenter: TopSitesPresenter = DefaultTopSitesPresenter(
+        view,
+        storage,
+        config,
+    ),
+) : LifecycleAwareFeature {
+
+    override fun start() {
+        presenter.start()
+    }
+
+    override fun stop() {
+        presenter.stop()
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesProvider.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesProvider.kt
new file mode 100644
index 0000000000..4ac8200901
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesProvider.kt
@@ -0,0 +1,20 @@
+/* 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 mozilla.components.feature.top.sites
+
+/**
+ * A contract that indicates how a top sites provider must behave.
+ */
+interface TopSitesProvider {
+
+    /**
+     * Provides a list of top sites.
+     *
+     * @param allowCache Whether or not the result may be provided from a previously
+     * cached response.
+     * @return a list of top sites from the provider.
+     */
+    suspend fun getTopSites(allowCache: Boolean = true): List<TopSite>
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesStorage.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesStorage.kt
new file mode 100644
index 0000000000..b27f8a3ae0
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesStorage.kt
@@ -0,0 +1,65 @@
+/* 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 mozilla.components.feature.top.sites
+
+import mozilla.components.browser.storage.sync.PlacesHistoryStorage
+import mozilla.components.support.base.observer.Observable
+
+/**
+ * Abstraction layer above the [PinnedSiteStorage] and [PlacesHistoryStorage] storages.
+ */
+interface TopSitesStorage : Observable<TopSitesStorage.Observer> {
+    /**
+     * Adds a new top site.
+     *
+     * @param title The title string.
+     * @param url The URL string.
+     * @param isDefault Whether or not the pinned site added should be a default pinned site. This
+     * is used to identify pinned sites that are added by the application.
+     */
+    fun addTopSite(title: String, url: String, isDefault: Boolean = false)
+
+    /**
+     * Removes the given [TopSite].
+     *
+     * @param topSite The top site.
+     */
+    fun removeTopSite(topSite: TopSite)
+
+    /**
+     * Updates the given [TopSite].
+     *
+     * @param topSite The top site.
+     * @param title The new title for the top site.
+     * @param url The new url for the top site.
+     */
+    fun updateTopSite(topSite: TopSite, title: String, url: String)
+
+    /**
+     * Return a unified list of top sites based on the given number of sites desired.
+     * If `frecencyConfig` is specified, fill in any missing top sites with frecent top site results.
+     *
+     * @param totalSites A total number of sites that will be retrieve if possible.
+     * @param frecencyConfig An instance of [TopSitesFrecencyConfig] that specifies which top
+     * frecent sites to be included.
+     * @param providerConfig An instance of [TopSitesProviderConfig] that specifies whether or
+     * not to fetch top sites from the [TopSitesProvider].
+     */
+    suspend fun getTopSites(
+        totalSites: Int,
+        frecencyConfig: TopSitesFrecencyConfig? = null,
+        providerConfig: TopSitesProviderConfig? = null,
+    ): List<TopSite>
+
+    /**
+     * Interface to be implemented by classes that want to observe the top site storage.
+     */
+    interface Observer {
+        /**
+         * Notify the observer when changes are made to the storage.
+         */
+        fun onStorageUpdated()
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesUseCases.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesUseCases.kt
new file mode 100644
index 0000000000..c7eb2f4fe6
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/TopSitesUseCases.kt
@@ -0,0 +1,67 @@
+/* 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 mozilla.components.feature.top.sites
+
+/**
+ * Contains use cases related to the top sites feature.
+ */
+class TopSitesUseCases(topSitesStorage: TopSitesStorage) {
+    /**
+     * Add a pinned site use case.
+     */
+    class AddPinnedSiteUseCase internal constructor(private val storage: TopSitesStorage) {
+        /**
+         * Adds a new [PinnedSite].
+         *
+         * @param title The title string.
+         * @param url The URL string.
+         */
+        operator fun invoke(title: String, url: String, isDefault: Boolean = false) {
+            storage.addTopSite(title, url, isDefault)
+        }
+    }
+
+    /**
+     * Remove a top site use case.
+     */
+    class RemoveTopSiteUseCase internal constructor(private val storage: TopSitesStorage) {
+        /**
+         * Removes the given [TopSite].
+         *
+         * @param topSite The top site.
+         */
+        operator fun invoke(topSite: TopSite) {
+            storage.removeTopSite(topSite)
+        }
+    }
+
+    /**
+     * Update a top site use case.
+     */
+    class UpdateTopSiteUseCase internal constructor(private val storage: TopSitesStorage) {
+        /**
+         * Updates the given [TopSite].
+         *
+         * @param topSite The top site.
+         * @param title The new title for the top site.
+         * @param url The new url for the top site.
+         */
+        operator fun invoke(topSite: TopSite, title: String, url: String) {
+            storage.updateTopSite(topSite, title, url)
+        }
+    }
+
+    val addPinnedSites: AddPinnedSiteUseCase by lazy {
+        AddPinnedSiteUseCase(topSitesStorage)
+    }
+
+    val removeTopSites: RemoveTopSiteUseCase by lazy {
+        RemoveTopSiteUseCase(topSitesStorage)
+    }
+
+    val updateTopSites: UpdateTopSiteUseCase by lazy {
+        UpdateTopSiteUseCase(topSitesStorage)
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/db/PinnedSiteDao.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/db/PinnedSiteDao.kt
new file mode 100644
index 0000000000..02c672b3fd
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/db/PinnedSiteDao.kt
@@ -0,0 +1,48 @@
+/* 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 mozilla.components.feature.top.sites.db
+
+import androidx.annotation.WorkerThread
+import androidx.room.Dao
+import androidx.room.Delete
+import androidx.room.Insert
+import androidx.room.Query
+import androidx.room.Transaction
+import androidx.room.Update
+
+/**
+ * Internal DAO for accessing [PinnedSiteEntity] instances.
+ */
+@Dao
+internal interface PinnedSiteDao {
+    @WorkerThread
+    @Insert
+    fun insertPinnedSite(site: PinnedSiteEntity): Long
+
+    @WorkerThread
+    @Update
+    fun updatePinnedSite(site: PinnedSiteEntity)
+
+    @WorkerThread
+    @Delete
+    fun deletePinnedSite(site: PinnedSiteEntity)
+
+    @WorkerThread
+    @Transaction
+    fun insertAllPinnedSites(sites: List<PinnedSiteEntity>): List<Long> {
+        return sites.map { entity ->
+            val id = insertPinnedSite(entity)
+            entity.id = id
+            id
+        }
+    }
+
+    @WorkerThread
+    @Query("SELECT * FROM top_sites")
+    fun getPinnedSites(): List<PinnedSiteEntity>
+
+    @Query("SELECT COUNT(*) FROM top_sites")
+    fun getPinnedSitesCount(): Int
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/db/PinnedSiteEntity.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/db/PinnedSiteEntity.kt
new file mode 100644
index 0000000000..fb106bf91f
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/db/PinnedSiteEntity.kt
@@ -0,0 +1,59 @@
+/* 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 mozilla.components.feature.top.sites.db
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+import mozilla.components.feature.top.sites.TopSite
+
+/**
+ * Internal entity representing a pinned site.
+ */
+@Entity(tableName = "top_sites")
+internal data class PinnedSiteEntity(
+    @PrimaryKey(autoGenerate = true)
+    @ColumnInfo(name = "id")
+    var id: Long? = null,
+
+    @ColumnInfo(name = "title")
+    var title: String,
+
+    @ColumnInfo(name = "url")
+    var url: String,
+
+    @ColumnInfo(name = "is_default")
+    var isDefault: Boolean = false,
+
+    @ColumnInfo(name = "created_at")
+    var createdAt: Long = System.currentTimeMillis(),
+) {
+    internal fun toTopSite(): TopSite =
+        if (isDefault) {
+            TopSite.Default(
+                id = id,
+                title = title,
+                url = url,
+                createdAt = createdAt,
+            )
+        } else {
+            TopSite.Pinned(
+                id = id,
+                title = title,
+                url = url,
+                createdAt = createdAt,
+            )
+        }
+}
+
+internal fun TopSite.toPinnedSite(): PinnedSiteEntity {
+    return PinnedSiteEntity(
+        id = id,
+        title = title ?: "",
+        url = url,
+        isDefault = this is TopSite.Default,
+        createdAt = createdAt ?: 0,
+    )
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/db/TopSiteDatabase.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/db/TopSiteDatabase.kt
new file mode 100644
index 0000000000..59aa469f54
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/db/TopSiteDatabase.kt
@@ -0,0 +1,107 @@
+/* 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 mozilla.components.feature.top.sites.db
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+import androidx.room.migration.Migration
+import androidx.sqlite.db.SupportSQLiteDatabase
+
+/**
+ * Internal database for storing top sites.
+ */
+@Database(entities = [PinnedSiteEntity::class], version = 3)
+internal abstract class TopSiteDatabase : RoomDatabase() {
+    abstract fun pinnedSiteDao(): PinnedSiteDao
+
+    companion object {
+        @Volatile
+        private var instance: TopSiteDatabase? = null
+
+        @Synchronized
+        fun get(context: Context): TopSiteDatabase {
+            instance?.let { return it }
+
+            return Room.databaseBuilder(
+                context,
+                TopSiteDatabase::class.java,
+                "top_sites",
+            ).addMigrations(
+                Migrations.migration_1_2,
+            ).addMigrations(
+                Migrations.migration_2_3,
+            ).build().also {
+                instance = it
+            }
+        }
+    }
+}
+
+internal object Migrations {
+    val migration_1_2 = object : Migration(1, 2) {
+        override fun migrate(db: SupportSQLiteDatabase) {
+            // Add the new is_default column and set is_default to 0 (false) for every entry.
+            db.execSQL(
+                "ALTER TABLE top_sites ADD COLUMN is_default INTEGER NOT NULL DEFAULT 0",
+            )
+
+            // Prior to version 2, pocket top sites, wikipedia and youtube were added as default
+            // sites in Fenix. Look for these entries and set is_default to 1 (true).
+            db.execSQL(
+                "UPDATE top_sites " +
+                    "SET is_default = 1 " +
+                    "WHERE url IN " +
+                    "('https://getpocket.com/fenix-top-articles', " +
+                    "'https://www.wikipedia.org/', " +
+                    "'https://www.youtube.com/')",
+            )
+        }
+    }
+
+    @Suppress("MagicNumber")
+    val migration_2_3 = object : Migration(2, 3) {
+        override fun migrate(db: SupportSQLiteDatabase) {
+            // Create a temporary top sites table of version 1.
+            db.execSQL(
+                "CREATE TABLE IF NOT EXISTS `top_sites_temp` (" +
+                    "`id` INTEGER PRIMARY KEY AUTOINCREMENT, " +
+                    "`title` TEXT NOT NULL, " +
+                    "`url` TEXT NOT NULL, " +
+                    "`is_default` INTEGER NOT NULL, " +
+                    "`created_at` INTEGER NOT NULL)",
+            )
+
+            // Insert every entry from the old table into the temporary top sites table.
+            db.execSQL(
+                "INSERT INTO top_sites_temp (title, url, created_at, is_default) " +
+                    "SELECT title, url, created_at, 0 FROM top_sites",
+            )
+
+            // Assume there are consumers of version 2 with the mismatched isDefault and is_default
+            // column name. Drop the old table.
+            db.execSQL(
+                "DROP TABLE top_sites",
+            )
+
+            // Rename the temporary table to top_sites.
+            db.execSQL(
+                "ALTER TABLE top_sites_temp RENAME TO top_sites",
+            )
+
+            // Prior to version 2, pocket top sites, wikipedia and youtube were added as default
+            // sites in Fenix. Look for these entries and set isDefault to 1 (true).
+            db.execSQL(
+                "UPDATE top_sites " +
+                    "SET is_default = 1 " +
+                    "WHERE url IN " +
+                    "('https://getpocket.com/fenix-top-articles', " +
+                    "'https://www.wikipedia.org/', " +
+                    "'https://www.youtube.com/')",
+            )
+        }
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/ext/TopFrecentSiteInfo.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/ext/TopFrecentSiteInfo.kt
new file mode 100644
index 0000000000..9fa513d6de
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/ext/TopFrecentSiteInfo.kt
@@ -0,0 +1,21 @@
+/* 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 mozilla.components.feature.top.sites.ext
+
+import mozilla.components.concept.storage.TopFrecentSiteInfo
+import mozilla.components.feature.top.sites.TopSite
+import mozilla.components.support.ktx.kotlin.tryGetHostFromUrl
+
+/**
+ * Returns a [TopSite] for the given [TopFrecentSiteInfo].
+ */
+fun TopFrecentSiteInfo.toTopSite(): TopSite {
+    return TopSite.Frecent(
+        id = null,
+        title = this.title?.takeIf(String::isNotBlank) ?: this.url.tryGetHostFromUrl(),
+        url = this.url,
+        createdAt = null,
+    )
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/ext/TopSite.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/ext/TopSite.kt
new file mode 100644
index 0000000000..c9d703484c
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/ext/TopSite.kt
@@ -0,0 +1,34 @@
+/* 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 mozilla.components.feature.top.sites.ext
+
+import mozilla.components.feature.top.sites.TopSite
+import mozilla.components.support.ktx.kotlin.getRepresentativeSnippet
+import mozilla.components.support.ktx.util.URLStringUtils
+
+/**
+ * Returns true if the given url is in the list top site and false otherwise.
+ *
+ * @param url The URL string.
+ */
+fun List<TopSite>.hasUrl(url: String): Boolean {
+    for (topSite in this) {
+        // Strip the https/http and WWW prefixes from the urls.
+        if (URLStringUtils.toDisplayUrl(topSite.url) == URLStringUtils.toDisplayUrl(url)) {
+            return true
+        }
+    }
+
+    return false
+}
+
+/**
+ * Returns true if the given url host/domain is in the list top site and false otherwise.
+ *
+ * @param url The URL string.
+ */
+fun List<TopSite>.hasHost(url: String): Boolean {
+    return this.any { it.url.getRepresentativeSnippet().equals(url.getRepresentativeSnippet(), true) }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/facts/TopSitesFacts.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/facts/TopSitesFacts.kt
new file mode 100644
index 0000000000..c667613d65
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/facts/TopSitesFacts.kt
@@ -0,0 +1,31 @@
+/* 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 mozilla.components.feature.top.sites.facts
+
+import mozilla.components.support.base.Component
+import mozilla.components.support.base.facts.Action
+import mozilla.components.support.base.facts.Fact
+import mozilla.components.support.base.facts.collect
+
+/**
+ * Facts emitted for telemetry related to [TopSitesFeature]
+ */
+class TopSitesFacts {
+    /**
+     * Items that specify which portion of the [TopSitesFeature] was interacted with
+     */
+    object Items {
+        const val COUNT = "count"
+    }
+}
+
+internal fun emitTopSitesCountFact(count: Int) {
+    Fact(
+        Component.FEATURE_TOP_SITES,
+        Action.INTERACTION,
+        TopSitesFacts.Items.COUNT,
+        count.toString(),
+    ).collect()
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/presenter/DefaultTopSitesPresenter.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/presenter/DefaultTopSitesPresenter.kt
new file mode 100644
index 0000000000..f1d9adb7fc
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/presenter/DefaultTopSitesPresenter.kt
@@ -0,0 +1,58 @@
+/* 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 mozilla.components.feature.top.sites.presenter
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import mozilla.components.feature.top.sites.TopSitesConfig
+import mozilla.components.feature.top.sites.TopSitesStorage
+import mozilla.components.feature.top.sites.view.TopSitesView
+import kotlin.coroutines.CoroutineContext
+
+/**
+ * Default implementation of [TopSitesPresenter]. Connects the [TopSitesView] with the
+ * [TopSitesStorage] to update the view whenever the storage is updated.
+ *
+ * @param view An implementor of [TopSitesView] that will be notified of changes to the storage.
+ * @param storage The top sites storage that stores pinned and frecent sites.
+ * @param config Lambda expression that returns [TopSitesConfig] which species the number of top
+ * sites to return and whether or not to include frequently visited sites.
+ */
+internal class DefaultTopSitesPresenter(
+    override val view: TopSitesView,
+    override val storage: TopSitesStorage,
+    private val config: () -> TopSitesConfig,
+    coroutineContext: CoroutineContext = Dispatchers.IO,
+) : TopSitesPresenter, TopSitesStorage.Observer {
+
+    private val scope = CoroutineScope(coroutineContext)
+
+    override fun start() {
+        onStorageUpdated()
+
+        storage.register(this)
+    }
+
+    override fun stop() {
+        storage.unregister(this)
+    }
+
+    override fun onStorageUpdated() {
+        val innerConfig = config.invoke()
+
+        scope.launch {
+            val topSites = storage.getTopSites(
+                totalSites = innerConfig.totalSites,
+                frecencyConfig = innerConfig.frecencyConfig,
+                providerConfig = innerConfig.providerConfig,
+            )
+
+            scope.launch(Dispatchers.Main) {
+                view.displayTopSites(topSites)
+            }
+        }
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/presenter/TopSitesPresenter.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/presenter/TopSitesPresenter.kt
new file mode 100644
index 0000000000..92d03492bb
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/presenter/TopSitesPresenter.kt
@@ -0,0 +1,17 @@
+/* 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 mozilla.components.feature.top.sites.presenter
+
+import mozilla.components.feature.top.sites.TopSitesStorage
+import mozilla.components.feature.top.sites.view.TopSitesView
+import mozilla.components.support.base.feature.LifecycleAwareFeature
+
+/**
+ * A presenter that connects the [TopSitesView] with the [TopSitesStorage].
+ */
+interface TopSitesPresenter : LifecycleAwareFeature {
+    val view: TopSitesView
+    val storage: TopSitesStorage
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/view/TopSitesView.kt b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/view/TopSitesView.kt
new file mode 100644
index 0000000000..58c62fff6d
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/main/java/mozilla/components/feature/top/sites/view/TopSitesView.kt
@@ -0,0 +1,17 @@
+/* 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 mozilla.components.feature.top.sites.view
+
+import mozilla.components.feature.top.sites.TopSite
+
+/**
+ * Implemented by the application for displaying onto the UI.
+ */
+interface TopSitesView {
+    /**
+     * Updates the UI with new list of top sites.
+     */
+    fun displayTopSites(topSites: List<TopSite>)
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/DefaultTopSitesStorageTest.kt b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/DefaultTopSitesStorageTest.kt
new file mode 100644
index 0000000000..db650a1b6b
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/DefaultTopSitesStorageTest.kt
@@ -0,0 +1,1169 @@
+/* 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 mozilla.components.feature.top.sites
+
+import android.net.Uri
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import mozilla.components.browser.storage.sync.PlacesHistoryStorage
+import mozilla.components.concept.storage.FrecencyThresholdOption
+import mozilla.components.concept.storage.TopFrecentSiteInfo
+import mozilla.components.feature.top.sites.ext.toTopSite
+import mozilla.components.support.test.any
+import mozilla.components.support.test.mock
+import mozilla.components.support.test.rule.MainCoroutineRule
+import mozilla.components.support.test.rule.runTestOnMain
+import mozilla.components.support.test.whenever
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.Mockito.anyInt
+import org.mockito.Mockito.never
+import org.mockito.Mockito.verify
+
+@ExperimentalCoroutinesApi
+@RunWith(AndroidJUnit4::class)
+class DefaultTopSitesStorageTest {
+
+    @get:Rule
+    val coroutinesTestRule = MainCoroutineRule()
+
+    private val pinnedSitesStorage: PinnedSiteStorage = mock()
+    private val historyStorage: PlacesHistoryStorage = mock()
+    private val topSitesProvider: TopSitesProvider = mock()
+
+    @Test
+    fun `default top sites are added to pinned site storage on init`() = runTestOnMain {
+        val defaultTopSites = listOf(
+            Pair("Mozilla", "https://mozilla.com"),
+            Pair("Firefox", "https://firefox.com"),
+        )
+
+        DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            defaultTopSites = defaultTopSites,
+            coroutineContext = coroutineContext,
+        )
+
+        verify(pinnedSitesStorage).addAllPinnedSites(defaultTopSites, isDefault = true)
+    }
+
+    @Test
+    fun `addPinnedSite`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        defaultTopSitesStorage.addTopSite("Mozilla", "https://mozilla.com", isDefault = false)
+
+        verify(pinnedSitesStorage).addPinnedSite(
+            "Mozilla",
+            "https://mozilla.com",
+            isDefault = false,
+        )
+    }
+
+    @Test
+    fun `removeTopSite`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val frecentSite = TopSite.Frecent(
+            id = 1,
+            title = "Mozilla",
+            url = "https://mozilla.com",
+            createdAt = 1,
+        )
+
+        defaultTopSitesStorage.removeTopSite(frecentSite)
+
+        verify(historyStorage).deleteVisitsFor(frecentSite.url)
+
+        val pinnedSite = TopSite.Pinned(
+            id = 2,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 2,
+        )
+
+        defaultTopSitesStorage.removeTopSite(pinnedSite)
+
+        verify(pinnedSitesStorage).removePinnedSite(pinnedSite)
+        verify(historyStorage).deleteVisitsFor(pinnedSite.url)
+
+        val defaultSite = TopSite.Default(
+            id = 3,
+            title = "Wikipedia",
+            url = "https://wikipedia.com",
+            createdAt = 3,
+        )
+
+        defaultTopSitesStorage.removeTopSite(defaultSite)
+
+        verify(pinnedSitesStorage).removePinnedSite(defaultSite)
+        verify(historyStorage).deleteVisitsFor(defaultSite.url)
+    }
+
+    @Test
+    fun `updateTopSite`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val defaultSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+
+        defaultTopSitesStorage.updateTopSite(defaultSite, "Mozilla Firefox", "https://mozilla.com")
+
+        verify(pinnedSitesStorage).updatePinnedSite(defaultSite, "Mozilla Firefox", "https://mozilla.com")
+
+        val pinnedSite = TopSite.Pinned(
+            id = 2,
+            title = "Wikipedia",
+            url = "https://wikipedia.com",
+            createdAt = 2,
+        )
+
+        defaultTopSitesStorage.updateTopSite(pinnedSite, "Wiki", "https://en.wikipedia.org/wiki/Wiki")
+
+        verify(pinnedSitesStorage).updatePinnedSite(pinnedSite, "Wiki", "https://en.wikipedia.org/wiki/Wiki")
+
+        val frecentSite = TopSite.Frecent(
+            id = 1,
+            title = "Mozilla",
+            url = "https://mozilla.com",
+            createdAt = 1,
+        )
+
+        defaultTopSitesStorage.updateTopSite(frecentSite, "Moz", "")
+
+        verify(pinnedSitesStorage, never()).updatePinnedSite(frecentSite, "Moz", "")
+    }
+
+    @Test
+    fun `GIVEN frecencyConfig and providerConfig are null WHEN getTopSites is called THEN only default and pinned sites are returned`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val defaultSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite = TopSite.Pinned(
+            id = 2,
+            title = "Wikipedia",
+            url = "https://wikipedia.com",
+            createdAt = 2,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSite,
+                pinnedSite,
+            ),
+        )
+        whenever(pinnedSitesStorage.getPinnedSitesCount()).thenReturn(2)
+
+        var topSites = defaultTopSitesStorage.getTopSites(totalSites = 0)
+
+        assertTrue(topSites.isEmpty())
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(totalSites = 1)
+
+        assertEquals(1, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(totalSites = 2)
+
+        assertEquals(2, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(totalSites = 5)
+
+        assertEquals(2, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+
+    @Test
+    fun `GIVEN providerConfig is specified WHEN getTopSites is called THEN default, pinned and provided top sites are returned`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            topSitesProvider = topSitesProvider,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val defaultSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite = TopSite.Pinned(
+            id = 2,
+            title = "Wikipedia",
+            url = "https://wikipedia.com",
+            createdAt = 2,
+        )
+        val providedSite = TopSite.Provided(
+            id = 3,
+            title = "Mozilla",
+            url = "https://mozilla.com",
+            clickUrl = "https://mozilla.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 3,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSite,
+                pinnedSite,
+            ),
+        )
+        whenever(topSitesProvider.getTopSites()).thenReturn(listOf(providedSite))
+
+        var topSites = defaultTopSitesStorage.getTopSites(totalSites = 0)
+
+        assertTrue(topSites.isEmpty())
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 1,
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        assertEquals(1, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 2,
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        assertEquals(2, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        assertEquals(3, topSites.size)
+        assertEquals(providedSite, topSites[0])
+        assertEquals(defaultSite, topSites[1])
+        assertEquals(pinnedSite, topSites[2])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = false,
+            ),
+        )
+
+        assertEquals(2, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+                maxThreshold = 8,
+            ),
+        )
+
+        assertEquals(3, topSites.size)
+        assertEquals(providedSite, topSites[0])
+        assertEquals(defaultSite, topSites[1])
+        assertEquals(pinnedSite, topSites[2])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+                maxThreshold = 2,
+            ),
+        )
+
+        assertEquals(2, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+
+    @Test
+    fun `GIVEN providerConfig with maxThreshold is specified WHEN getTopSites is called THEN the correct number of provided top sites are returned`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            topSitesProvider = topSitesProvider,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val defaultSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite1 = TopSite.Pinned(
+            id = 2,
+            title = "Wikipedia",
+            url = "https://wikipedia.com",
+            createdAt = 2,
+        )
+        val pinnedSite2 = TopSite.Pinned(
+            id = 3,
+            title = "Example",
+            url = "https://example.com",
+            createdAt = 3,
+        )
+        val providedSite1 = TopSite.Provided(
+            id = 4,
+            title = "Mozilla",
+            url = "https://mozilla.com",
+            clickUrl = "https://mozilla.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 3,
+        )
+        val providedSite2 = TopSite.Provided(
+            id = 5,
+            title = "Pocket",
+            url = "https://pocket.com",
+            clickUrl = "https://mozilla.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 3,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSite,
+                pinnedSite1,
+                pinnedSite2,
+                defaultSite,
+                pinnedSite1,
+                pinnedSite2,
+            ),
+        )
+        whenever(topSitesProvider.getTopSites()).thenReturn(listOf(providedSite1, providedSite2))
+
+        var topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 8,
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+                maxThreshold = 8,
+            ),
+        )
+
+        assertEquals(8, topSites.size)
+        assertEquals(providedSite1, topSites[0])
+        assertEquals(providedSite2, topSites[1])
+        assertEquals(defaultSite, topSites[2])
+        assertEquals(pinnedSite1, topSites[3])
+        assertEquals(pinnedSite2, topSites[4])
+        assertEquals(defaultSite, topSites[5])
+        assertEquals(pinnedSite1, topSites[6])
+        assertEquals(pinnedSite2, topSites[7])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSite,
+                pinnedSite1,
+                pinnedSite2,
+                defaultSite,
+                pinnedSite1,
+                pinnedSite2,
+                defaultSite,
+            ),
+        )
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 8,
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+                maxThreshold = 8,
+            ),
+        )
+
+        assertEquals(8, topSites.size)
+        assertEquals(providedSite1, topSites[0])
+        assertEquals(defaultSite, topSites[1])
+        assertEquals(pinnedSite1, topSites[2])
+        assertEquals(pinnedSite2, topSites[3])
+        assertEquals(defaultSite, topSites[4])
+        assertEquals(pinnedSite1, topSites[5])
+        assertEquals(pinnedSite2, topSites[6])
+        assertEquals(defaultSite, topSites[7])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSite,
+                pinnedSite1,
+                pinnedSite2,
+                defaultSite,
+                pinnedSite1,
+                pinnedSite2,
+                defaultSite,
+                pinnedSite1,
+            ),
+        )
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 8,
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+                maxThreshold = 8,
+            ),
+        )
+
+        assertEquals(8, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite1, topSites[1])
+        assertEquals(pinnedSite2, topSites[2])
+        assertEquals(defaultSite, topSites[3])
+        assertEquals(pinnedSite1, topSites[4])
+        assertEquals(pinnedSite2, topSites[5])
+        assertEquals(defaultSite, topSites[6])
+        assertEquals(pinnedSite1, topSites[7])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+
+    @Test
+    fun `GIVEN frecencyConfig and providerConfig are specified WHEN getTopSites is called THEN default, pinned, provided and frecent top sites are returned`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            topSitesProvider = topSitesProvider,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val defaultSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite = TopSite.Pinned(
+            id = 2,
+            title = "Wikipedia",
+            url = "https://wikipedia.com",
+            createdAt = 2,
+        )
+        val providedSite = TopSite.Provided(
+            id = 3,
+            title = "Mozilla",
+            url = "https://mozilla.com",
+            clickUrl = "https://mozilla.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 3,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSite,
+                pinnedSite,
+            ),
+        )
+        whenever(topSitesProvider.getTopSites()).thenReturn(listOf(providedSite))
+
+        val frecentSite1 = TopFrecentSiteInfo("https://getpocket.com", "Pocket")
+        whenever(historyStorage.getTopFrecentSites(anyInt(), any())).thenReturn(listOf(frecentSite1))
+
+        var topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 0,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        assertTrue(topSites.isEmpty())
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 1,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        assertEquals(1, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 2,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        assertEquals(2, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 3,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        assertEquals(3, topSites.size)
+        assertEquals(providedSite, topSites[0])
+        assertEquals(defaultSite, topSites[1])
+        assertEquals(pinnedSite, topSites[2])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        assertEquals(4, topSites.size)
+        assertEquals(providedSite, topSites[0])
+        assertEquals(defaultSite, topSites[1])
+        assertEquals(pinnedSite, topSites[2])
+        assertEquals(frecentSite1.toTopSite(), topSites[3])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+
+    @Test
+    fun `getTopSites returns pinned and frecent sites when frecencyConfig is specified`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val defaultSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite = TopSite.Pinned(
+            id = 2,
+            title = "Wikipedia",
+            url = "https://wikipedia.com",
+            createdAt = 2,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSite,
+                pinnedSite,
+            ),
+        )
+        whenever(pinnedSitesStorage.getPinnedSitesCount()).thenReturn(2)
+
+        val frecentSite1 = TopFrecentSiteInfo("https://mozilla.com", "Mozilla")
+        whenever(historyStorage.getTopFrecentSites(anyInt(), any())).thenReturn(listOf(frecentSite1))
+
+        var topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 0,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+        )
+
+        assertTrue(topSites.isEmpty())
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 1,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+        )
+
+        assertEquals(1, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 2,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+        )
+
+        assertEquals(2, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+        )
+
+        assertEquals(3, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(frecentSite1.toTopSite(), topSites[2])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        val frecentSite2 = TopFrecentSiteInfo("https://example.com", "Example")
+        val frecentSite3 = TopFrecentSiteInfo("https://getpocket.com", "Pocket")
+        whenever(historyStorage.getTopFrecentSites(anyInt(), any())).thenReturn(
+            listOf(
+                frecentSite1,
+                frecentSite2,
+                frecentSite3,
+            ),
+        )
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+        )
+
+        assertEquals(5, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(frecentSite1.toTopSite(), topSites[2])
+        assertEquals(frecentSite2.toTopSite(), topSites[3])
+        assertEquals(frecentSite3.toTopSite(), topSites[4])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        val frecentSite4 = TopFrecentSiteInfo("https://example2.com", "Example2")
+        whenever(historyStorage.getTopFrecentSites(anyInt(), any())).thenReturn(
+            listOf(
+                frecentSite1,
+                frecentSite2,
+                frecentSite3,
+                frecentSite4,
+            ),
+        )
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+        )
+
+        assertEquals(5, topSites.size)
+        assertEquals(defaultSite, topSites[0])
+        assertEquals(pinnedSite, topSites[1])
+        assertEquals(frecentSite1.toTopSite(), topSites[2])
+        assertEquals(frecentSite2.toTopSite(), topSites[3])
+        assertEquals(frecentSite3.toTopSite(), topSites[4])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+
+    @Test
+    fun `getTopSites filters out frecent sites that already exist in pinned sites`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val defaultSiteFirefox = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite1 = TopSite.Pinned(
+            id = 2,
+            title = "Wikipedia",
+            url = "https://wikipedia.com",
+            createdAt = 2,
+        )
+        val pinnedSite2 = TopSite.Pinned(
+            id = 3,
+            title = "Example",
+            url = "https://example.com",
+            createdAt = 3,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSiteFirefox,
+                pinnedSite1,
+                pinnedSite2,
+            ),
+        )
+        whenever(pinnedSitesStorage.getPinnedSitesCount()).thenReturn(3)
+
+        val frecentSiteWithNoTitle = TopFrecentSiteInfo("https://mozilla.com", "")
+        val frecentSiteFirefox = TopFrecentSiteInfo("https://firefox.com", "Firefox")
+        val frecentSite1 = TopFrecentSiteInfo("https://getpocket.com", "Pocket")
+        val frecentSite2 = TopFrecentSiteInfo("https://www.example.com", "Example")
+
+        whenever(historyStorage.getTopFrecentSites(anyInt(), any())).thenReturn(
+            listOf(
+                frecentSiteWithNoTitle,
+                frecentSiteFirefox,
+                frecentSite1,
+                frecentSite2,
+            ),
+        )
+
+        val topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+        )
+
+        verify(historyStorage).getTopFrecentSites(5, frecencyThreshold = FrecencyThresholdOption.NONE)
+
+        assertEquals(5, topSites.size)
+        assertEquals(defaultSiteFirefox, topSites[0])
+        assertEquals(pinnedSite1, topSites[1])
+        assertEquals(pinnedSite2, topSites[2])
+        assertEquals(frecentSiteWithNoTitle.toTopSite(), topSites[3])
+        assertEquals(frecentSite1.toTopSite(), topSites[4])
+        assertEquals("mozilla.com", frecentSiteWithNoTitle.toTopSite().title)
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+
+    @Test
+    fun `GIVEN providerFilter is set WHEN getTopSites is called THEN the provided top sites are filtered`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            topSitesProvider = topSitesProvider,
+            coroutineContext = coroutineContext,
+        )
+
+        val filteredUrl = "https://test.com"
+
+        val providerConfig = TopSitesProviderConfig(
+            showProviderTopSites = true,
+            providerFilter = { topSite -> topSite.url != filteredUrl },
+        )
+
+        val defaultSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite = TopSite.Pinned(
+            id = 2,
+            title = "Test",
+            url = filteredUrl,
+            createdAt = 2,
+        )
+        val providedSite = TopSite.Provided(
+            id = 3,
+            title = "Mozilla",
+            url = "https://mozilla.com",
+            clickUrl = "https://mozilla.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 3,
+        )
+        val providedFilteredSite = TopSite.Provided(
+            id = 3,
+            title = "Filtered",
+            url = filteredUrl,
+            clickUrl = "https://test.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 3,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSite,
+                pinnedSite,
+            ),
+        )
+        whenever(topSitesProvider.getTopSites()).thenReturn(listOf(providedSite, providedFilteredSite))
+
+        val frecentSite1 = TopFrecentSiteInfo("https://getpocket.com", "Pocket")
+        whenever(historyStorage.getTopFrecentSites(anyInt(), any())).thenReturn(listOf(frecentSite1))
+
+        var topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 3,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+            providerConfig = providerConfig,
+        )
+
+        assertEquals(3, topSites.size)
+        assertEquals(providedSite, topSites[0])
+        assertEquals(defaultSite, topSites[1])
+        assertEquals(pinnedSite, topSites[2])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 4,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+            providerConfig = providerConfig,
+        )
+
+        assertEquals(4, topSites.size)
+        assertEquals(providedSite, topSites[0])
+        assertEquals(defaultSite, topSites[1])
+        assertEquals(pinnedSite, topSites[2])
+        assertEquals(frecentSite1.toTopSite(), topSites[3])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+
+    @Test
+    fun `GIVEN frecent top sites exist as a pinned or provided site WHEN top sites are retrieved THEN filters out frecent sites that already exist in pinned or provided sites`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            topSitesProvider = topSitesProvider,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val defaultSiteFirefox = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite1 = TopSite.Pinned(
+            id = 2,
+            title = "Wikipedia",
+            url = "https://wikipedia.com",
+            createdAt = 2,
+        )
+        val pinnedSite2 = TopSite.Pinned(
+            id = 3,
+            title = "Example",
+            url = "https://example.com",
+            createdAt = 3,
+        )
+        val providedSite = TopSite.Provided(
+            id = 3,
+            title = "Firefox",
+            url = "https://getfirefox.com",
+            clickUrl = "https://getfirefox.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 3,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSiteFirefox,
+                pinnedSite1,
+                pinnedSite2,
+            ),
+        )
+        whenever(pinnedSitesStorage.getPinnedSitesCount()).thenReturn(3)
+        whenever(topSitesProvider.getTopSites()).thenReturn(listOf(providedSite))
+
+        val frecentSiteWithNoTitle = TopFrecentSiteInfo("https://mozilla.com", "")
+        val frecentSiteFirefox = TopFrecentSiteInfo("https://firefox.com", "Firefox")
+        val frecentSite1 = TopFrecentSiteInfo("https://getpocket.com", "Pocket")
+        val frecentSite2 = TopFrecentSiteInfo("https://www.example.com", "Example")
+        val frecentSite3 = TopFrecentSiteInfo("https://www.getfirefox.com", "Firefox")
+
+        whenever(historyStorage.getTopFrecentSites(anyInt(), any())).thenReturn(
+            listOf(
+                frecentSiteWithNoTitle,
+                frecentSiteFirefox,
+                frecentSite1,
+                frecentSite2,
+                frecentSite3,
+            ),
+        )
+
+        val topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 10,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        verify(historyStorage).getTopFrecentSites(10, frecencyThreshold = FrecencyThresholdOption.NONE)
+
+        assertEquals(6, topSites.size)
+        assertEquals(providedSite, topSites[0])
+        assertEquals(defaultSiteFirefox, topSites[1])
+        assertEquals(pinnedSite1, topSites[2])
+        assertEquals(pinnedSite2, topSites[3])
+        assertEquals(frecentSiteWithNoTitle.toTopSite(), topSites[4])
+        assertEquals(frecentSite1.toTopSite(), topSites[5])
+        assertEquals("mozilla.com", frecentSiteWithNoTitle.toTopSite().title)
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+
+    @Test
+    fun `GIVEN frecencyFilter is set WHEN getTopSites is called THEN the frecent top sites are filtered`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            topSitesProvider = topSitesProvider,
+            coroutineContext = coroutineContext,
+        )
+
+        val filterMethod: ((TopSite) -> Boolean) = { topSite ->
+            val uri = Uri.parse(topSite.url)
+            if (!uri.queryParameterNames.contains("key")) {
+                true
+            } else {
+                uri.getQueryParameter("key") != "value"
+            }
+        }
+
+        val filteredUrl = "https://test.com/?key=value"
+
+        val frecencyConfig = TopSitesFrecencyConfig(
+            frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            frecencyFilter = filterMethod,
+        )
+
+        val defaultSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite = TopSite.Pinned(
+            id = 2,
+            title = "Test",
+            url = "https://test.com",
+            createdAt = 2,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSite,
+                pinnedSite,
+            ),
+        )
+
+        val providedFilteredSite = TopSite.Provided(
+            id = 3,
+            title = "Filtered",
+            url = "https://test.com",
+            clickUrl = "https://test.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 3,
+        )
+
+        whenever(topSitesProvider.getTopSites()).thenReturn(
+            listOf(
+                providedFilteredSite,
+            ),
+        )
+
+        val frecentSite = TopFrecentSiteInfo("https://getpocket.com", "Pocket")
+
+        val frecentFilteredSite = TopFrecentSiteInfo(filteredUrl, "testSearch")
+
+        whenever(historyStorage.getTopFrecentSites(anyInt(), any())).thenReturn(
+            listOf(
+                frecentSite,
+                frecentFilteredSite,
+            ),
+        )
+
+        var topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 4,
+            frecencyConfig = frecencyConfig,
+            providerConfig = TopSitesProviderConfig(showProviderTopSites = true),
+        )
+
+        assertEquals(4, topSites.size)
+        assertTrue(topSites.contains(frecentSite.toTopSite()))
+        assertTrue(topSites.contains(providedFilteredSite))
+        assertTrue(topSites.contains(defaultSite))
+        assertTrue(topSites.contains(pinnedSite))
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+
+        topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 5,
+            frecencyConfig = frecencyConfig,
+            providerConfig = TopSitesProviderConfig(showProviderTopSites = true),
+        )
+
+        assertEquals(4, topSites.size)
+        assertTrue(topSites.contains(frecentSite.toTopSite()))
+        assertTrue(topSites.contains(providedFilteredSite))
+        assertTrue(topSites.contains(defaultSite))
+        assertTrue(topSites.contains(pinnedSite))
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+
+    @Test
+    fun `GIVEN frecent top sites host exist as a provided site WHEN top sites are retrieved THEN filters out frecent sites with host that already exist in provided sites`() = runTestOnMain {
+        val defaultTopSitesStorage = DefaultTopSitesStorage(
+            pinnedSitesStorage = pinnedSitesStorage,
+            historyStorage = historyStorage,
+            topSitesProvider = topSitesProvider,
+            defaultTopSites = listOf(),
+            coroutineContext = coroutineContext,
+        )
+
+        val defaultSiteFirefox = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+        val pinnedSite1 = TopSite.Pinned(
+            id = 2,
+            title = "Google",
+            url = "https://google.com",
+            createdAt = 2,
+        )
+        val providedSite1 = TopSite.Provided(
+            id = 3,
+            title = "Amazon",
+            url = "https://www.amazon.com/?tag=sponsored-shortcut",
+            clickUrl = "https://www.amazon.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 3,
+        )
+        val providedSite2 = TopSite.Provided(
+            id = 4,
+            title = "UnderArmour",
+            url = "https://www.underarmour.com/?tag=sponsored-shortcut",
+            clickUrl = "https://www.underarmour.com/click",
+            imageUrl = "https://test.com/image2.jpg",
+            impressionUrl = "https://example.com",
+            createdAt = 4,
+        )
+
+        whenever(pinnedSitesStorage.getPinnedSites()).thenReturn(
+            listOf(
+                defaultSiteFirefox,
+                pinnedSite1,
+            ),
+        )
+        whenever(pinnedSitesStorage.getPinnedSitesCount()).thenReturn(2)
+        whenever(topSitesProvider.getTopSites()).thenReturn(
+            listOf(
+                providedSite1,
+                providedSite2,
+            ),
+        )
+
+        val frecentSite1 = TopFrecentSiteInfo("https://www.amazon.com", "Amazon")
+        val frecentSite2 = TopFrecentSiteInfo("https://www.amazon.com/Wireless-Charging-Station-Charger-AirPods/dp/B09KTY5GM7?pf_rd_r=NCJV8SPRQ2K43XM6WWKS&pf_rd_p=7b590888-dba4-4742-b2f2-7b20b1700e00&pd_rd_r=4fbaf1df-96be-470a-9811-0bc2aa8b415f&pd_rd_w=Viqqz&pd_rd_wg=9Emfa", "Amazon")
+        val frecentSite3 = TopFrecentSiteInfo("https://www.underarmour.com", "UnderArmour")
+        val frecentSite4 = TopFrecentSiteInfo("https://www.underarmour.com/en-us/p/curry_brand_shoes_and_gear/mens_curry_sour_then_sweet_crewneck/195253758836.html", "UnderArmour")
+        val frecentSite5 = TopFrecentSiteInfo("https://www.example.com", "Example")
+        val frecentSite6 = TopFrecentSiteInfo("https://www.getfirefox.com", "Firefox")
+
+        whenever(historyStorage.getTopFrecentSites(anyInt(), any())).thenReturn(
+            listOf(
+                frecentSite1,
+                frecentSite2,
+                frecentSite3,
+                frecentSite4,
+                frecentSite5,
+                frecentSite6,
+            ),
+        )
+
+        val topSites = defaultTopSitesStorage.getTopSites(
+            totalSites = 10,
+            frecencyConfig = TopSitesFrecencyConfig(
+                frecencyTresholdOption = FrecencyThresholdOption.NONE,
+            ),
+            providerConfig = TopSitesProviderConfig(
+                showProviderTopSites = true,
+            ),
+        )
+
+        verify(historyStorage).getTopFrecentSites(10, frecencyThreshold = FrecencyThresholdOption.NONE)
+
+        assertEquals(6, topSites.size)
+        assertEquals(providedSite1, topSites[0])
+        assertEquals(providedSite2, topSites[1])
+        assertFalse(topSites.contains(frecentSite1.toTopSite()))
+        assertFalse(topSites.contains(frecentSite2.toTopSite()))
+        assertFalse(topSites.contains(frecentSite3.toTopSite()))
+        assertFalse(topSites.contains(frecentSite4.toTopSite()))
+        assertEquals(defaultSiteFirefox, topSites[2])
+        assertEquals(pinnedSite1, topSites[3])
+        assertEquals(defaultTopSitesStorage.cachedTopSites, topSites)
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/PinnedSitesStorageTest.kt b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/PinnedSitesStorageTest.kt
new file mode 100644
index 0000000000..69c30de8d9
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/PinnedSitesStorageTest.kt
@@ -0,0 +1,135 @@
+/* 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 mozilla.components.feature.top.sites
+
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.runTest
+import mozilla.components.feature.top.sites.db.PinnedSiteDao
+import mozilla.components.feature.top.sites.db.PinnedSiteEntity
+import mozilla.components.feature.top.sites.db.TopSiteDatabase
+import mozilla.components.support.test.mock
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Test
+import org.mockito.Mockito.verify
+import org.mockito.Mockito.`when`
+
+@ExperimentalCoroutinesApi // for runTest
+class PinnedSitesStorageTest {
+
+    @Test
+    fun addAllDefaultSites() = runTest {
+        val storage = PinnedSiteStorage(mock())
+        val dao = mockDao(storage)
+
+        storage.currentTimeMillis = { 42 }
+
+        storage.addAllPinnedSites(
+            listOf(
+                Pair("Mozilla", "https://www.mozilla.org"),
+                Pair("Firefox", "https://www.firefox.com"),
+                Pair("Wikipedia", "https://www.wikipedia.com"),
+                Pair("Pocket", "https://www.getpocket.com"),
+            ),
+            isDefault = true,
+        )
+
+        verify(dao).insertAllPinnedSites(
+            listOf(
+                PinnedSiteEntity(title = "Mozilla", url = "https://www.mozilla.org", isDefault = true, createdAt = 42),
+                PinnedSiteEntity(title = "Firefox", url = "https://www.firefox.com", isDefault = true, createdAt = 42),
+                PinnedSiteEntity(title = "Wikipedia", url = "https://www.wikipedia.com", isDefault = true, createdAt = 42),
+                PinnedSiteEntity(title = "Pocket", url = "https://www.getpocket.com", isDefault = true, createdAt = 42),
+            ),
+        )
+
+        Unit
+    }
+
+    @Test
+    fun addPinnedSite() = runTest {
+        val storage = PinnedSiteStorage(mock())
+        val dao = mockDao(storage)
+
+        storage.currentTimeMillis = { 3 }
+
+        storage.addPinnedSite("Mozilla", "https://www.mozilla.org")
+        storage.addPinnedSite("Firefox", "https://www.firefox.com", isDefault = true)
+
+        // PinnedSiteDao.insertPinnedSite is actually called with "id = null", but due to an
+        // extraneous assignment ("entity.id = ") in PinnedSiteStorage.addPinnedSite we can for now
+        // only verify the call with "id = 0". See issue #9708.
+        verify(dao).insertPinnedSite(PinnedSiteEntity(id = 0, title = "Mozilla", url = "https://www.mozilla.org", isDefault = false, createdAt = 3))
+        verify(dao).insertPinnedSite(PinnedSiteEntity(id = 0, title = "Firefox", url = "https://www.firefox.com", isDefault = true, createdAt = 3))
+
+        Unit
+    }
+
+    @Test
+    fun removePinnedSite() = runTest {
+        val storage = PinnedSiteStorage(mock())
+        val dao = mockDao(storage)
+
+        storage.removePinnedSite(TopSite.Pinned(1, "Mozilla", "https://www.mozilla.org", 1))
+        storage.removePinnedSite(TopSite.Default(2, "Firefox", "https://www.firefox.com", 1))
+
+        verify(dao).deletePinnedSite(PinnedSiteEntity(1, "Mozilla", "https://www.mozilla.org", false, 1))
+        verify(dao).deletePinnedSite(PinnedSiteEntity(2, "Firefox", "https://www.firefox.com", true, 1))
+    }
+
+    @Test
+    fun getPinnedSites() = runTest {
+        val storage = PinnedSiteStorage(mock())
+        val dao = mockDao(storage)
+
+        `when`(dao.getPinnedSites()).thenReturn(
+            listOf(
+                PinnedSiteEntity(1, "Mozilla", "https://www.mozilla.org", false, 10),
+                PinnedSiteEntity(2, "Firefox", "https://www.firefox.com", true, 10),
+            ),
+        )
+        `when`(dao.getPinnedSitesCount()).thenReturn(2)
+
+        val topSites = storage.getPinnedSites()
+        val topSitesCount = storage.getPinnedSitesCount()
+
+        assertNotNull(topSites)
+        assertEquals(2, topSites.size)
+        assertEquals(2, topSitesCount)
+
+        with(topSites[0]) {
+            assertEquals(1L, id)
+            assertEquals("Mozilla", title)
+            assertEquals("https://www.mozilla.org", url)
+            assertEquals(10L, createdAt)
+        }
+
+        with(topSites[1]) {
+            assertEquals(2L, id)
+            assertEquals("Firefox", title)
+            assertEquals("https://www.firefox.com", url)
+            assertEquals(10L, createdAt)
+        }
+    }
+
+    @Test
+    fun updatePinnedSite() = runTest {
+        val storage = PinnedSiteStorage(mock())
+        val dao = mockDao(storage)
+
+        val site = TopSite.Pinned(1, "Mozilla", "https://www.mozilla.org", 1)
+        storage.updatePinnedSite(site, "Mozilla (IT)", "https://www.mozilla.org/it")
+
+        verify(dao).updatePinnedSite(PinnedSiteEntity(1, "Mozilla (IT)", "https://www.mozilla.org/it", false, 1))
+    }
+
+    private fun mockDao(storage: PinnedSiteStorage): PinnedSiteDao {
+        val db = mock<TopSiteDatabase>()
+        storage.database = lazy { db }
+        val dao = mock<PinnedSiteDao>()
+        `when`(db.pinnedSiteDao()).thenReturn(dao)
+        return dao
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/TopSitesFeatureTest.kt b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/TopSitesFeatureTest.kt
new file mode 100644
index 0000000000..21d7274e7c
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/TopSitesFeatureTest.kt
@@ -0,0 +1,34 @@
+/* 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 mozilla.components.feature.top.sites
+
+import mozilla.components.feature.top.sites.presenter.TopSitesPresenter
+import mozilla.components.feature.top.sites.view.TopSitesView
+import mozilla.components.support.test.mock
+import org.junit.Test
+import org.mockito.Mockito.verify
+
+class TopSitesFeatureTest {
+
+    private val view: TopSitesView = mock()
+    private val storage: TopSitesStorage = mock()
+    private val presenter: TopSitesPresenter = mock()
+    private val config: () -> TopSitesConfig = mock()
+    private val feature: TopSitesFeature = TopSitesFeature(view, storage, config, presenter)
+
+    @Test
+    fun start() {
+        feature.start()
+
+        verify(presenter).start()
+    }
+
+    @Test
+    fun stop() {
+        feature.stop()
+
+        verify(presenter).stop()
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/TopSitesUseCasesTest.kt b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/TopSitesUseCasesTest.kt
new file mode 100644
index 0000000000..6c100cdb57
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/TopSitesUseCasesTest.kt
@@ -0,0 +1,65 @@
+/* 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 mozilla.components.feature.top.sites
+
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.runTest
+import mozilla.components.support.test.mock
+import org.junit.Test
+import org.mockito.Mockito.verify
+
+@ExperimentalCoroutinesApi // for runTest
+
+class TopSitesUseCasesTest {
+
+    @Test
+    fun `AddPinnedSiteUseCase`() = runTest {
+        val topSitesStorage: TopSitesStorage = mock()
+        val useCases = TopSitesUseCases(topSitesStorage)
+
+        useCases.addPinnedSites("Mozilla", "https://www.mozilla.org", isDefault = true)
+        verify(topSitesStorage).addTopSite(
+            "Mozilla",
+            "https://www.mozilla.org",
+            isDefault = true,
+        )
+    }
+
+    @Test
+    fun `RemoveTopSiteUseCase`() = runTest {
+        val topSitesStorage: TopSitesStorage = mock()
+        val topSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+
+        val useCases = TopSitesUseCases(topSitesStorage)
+
+        useCases.removeTopSites(topSite)
+
+        verify(topSitesStorage).removeTopSite(topSite)
+    }
+
+    @Test
+    fun `UpdateTopSiteUseCase`() = runTest {
+        val topSitesStorage: TopSitesStorage = mock()
+        val topSite = TopSite.Default(
+            id = 1,
+            title = "Firefox",
+            url = "https://firefox.com",
+            createdAt = 1,
+        )
+
+        val useCases = TopSitesUseCases(topSitesStorage)
+
+        val title = "New title"
+        val url = "https://www.example.com/new-url"
+        useCases.updateTopSites(topSite, title, url)
+
+        verify(topSitesStorage).updateTopSite(topSite, title, url)
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/ext/TopSiteTest.kt b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/ext/TopSiteTest.kt
new file mode 100644
index 0000000000..210c6e0b09
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/ext/TopSiteTest.kt
@@ -0,0 +1,108 @@
+/* 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 mozilla.components.feature.top.sites.ext
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import mozilla.components.feature.top.sites.TopSite
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class TopSiteTest {
+
+    @Test
+    fun hasUrl() {
+        val topSites = listOf(
+            TopSite.Frecent(
+                id = 1,
+                title = "Mozilla",
+                url = "https://mozilla.com",
+                createdAt = 1,
+            ),
+        )
+
+        assertTrue(topSites.hasUrl("https://mozilla.com"))
+        assertTrue(topSites.hasUrl("https://www.mozilla.com"))
+        assertTrue(topSites.hasUrl("http://mozilla.com"))
+        assertTrue(topSites.hasUrl("http://www.mozilla.com"))
+        assertTrue(topSites.hasUrl("mozilla.com"))
+        assertTrue(topSites.hasUrl("https://mozilla.com/"))
+
+        assertFalse(topSites.hasUrl("https://m.mozilla.com"))
+        assertFalse(topSites.hasUrl("https://mozilla.com/path"))
+        assertFalse(topSites.hasUrl("https://firefox.com"))
+        assertFalse(topSites.hasUrl("https://mozilla.com/path/is/long"))
+        assertFalse(topSites.hasUrl("https://mozilla.com/path#anchor"))
+    }
+
+    @Test
+    fun hasHostOneItem() {
+        val topSites = listOf(
+            TopSite.Frecent(
+                id = 1,
+                title = "Amazon",
+                url = "https://amazon.com/playstation",
+                createdAt = 1,
+            ),
+        )
+
+        assertTrue(topSites.hasHost("https://amazon.com"))
+        assertTrue(topSites.hasHost("https://www.amazon.com"))
+        assertTrue(topSites.hasHost("http://amazon.com"))
+        assertTrue(topSites.hasHost("http://www.amazon.com"))
+        assertTrue(topSites.hasHost("amazon.com"))
+        assertTrue(topSites.hasHost("https://amazon.com/"))
+        assertTrue(topSites.hasHost("HTTPS://AMAZON.COM/"))
+        assertFalse(topSites.hasHost("https://amzn.com/"))
+        assertFalse(topSites.hasHost("https://aws.amazon.com/"))
+        assertFalse(topSites.hasHost("https://youtube.com/"))
+    }
+
+    @Test
+    fun hasHostNoItem() {
+        val topSites = emptyList<TopSite.Frecent>()
+
+        assertFalse(topSites.hasHost("https://amazon.com"))
+        assertFalse(topSites.hasHost("https://www.amazon.com"))
+        assertFalse(topSites.hasHost("http://amazon.com"))
+        assertFalse(topSites.hasHost("http://www.amazon.com"))
+        assertFalse(topSites.hasHost("amazon.com"))
+        assertFalse(topSites.hasHost("https://amazon.com/"))
+        assertFalse(topSites.hasHost("HTTPS://AMAZON.COM/"))
+        assertFalse(topSites.hasHost("https://amzn.com/"))
+        assertFalse(topSites.hasHost("https://aws.amazon.com/"))
+    }
+
+    @Test
+    fun hasHostMultipleItems() {
+        val topSites = listOf(
+            TopSite.Frecent(
+                id = 1,
+                title = "Amazon",
+                url = "https://amazon.com/playstation",
+                createdAt = 1,
+            ),
+            TopSite.Frecent(
+                id = 2,
+                title = "Hotels",
+                url = "https://www.hotels.com/",
+                createdAt = 2,
+            ),
+            TopSite.Frecent(
+                id = 3,
+                title = "eBay",
+                url = "https://www.ebay.com/n/all-categories",
+                createdAt = 3,
+            ),
+        )
+
+        assertTrue(topSites.hasHost("https://amazon.com"))
+        assertTrue(topSites.hasHost("https://hotels.com"))
+        assertTrue(topSites.hasHost("http://ebay.com"))
+        assertFalse(topSites.hasHost("http://google.com"))
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/fact/TopSitesFactsTest.kt b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/fact/TopSitesFactsTest.kt
new file mode 100644
index 0000000000..a8ab8eded8
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/fact/TopSitesFactsTest.kt
@@ -0,0 +1,44 @@
+/* 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 mozilla.components.feature.top.sites.fact
+
+import mozilla.components.feature.top.sites.facts.TopSitesFacts
+import mozilla.components.feature.top.sites.facts.emitTopSitesCountFact
+import mozilla.components.support.base.Component
+import mozilla.components.support.base.facts.Action
+import mozilla.components.support.base.facts.processor.CollectionProcessor
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class TopSitesFactsTest {
+
+    @Test
+    fun `Emits facts for current state`() {
+        CollectionProcessor.withFactCollection { facts ->
+
+            assertEquals(0, facts.size)
+
+            emitTopSitesCountFact(5)
+
+            assertEquals(1, facts.size)
+            facts[0].apply {
+                assertEquals(Component.FEATURE_TOP_SITES, component)
+                assertEquals(Action.INTERACTION, action)
+                assertEquals(TopSitesFacts.Items.COUNT, item)
+                assertEquals(5, value?.toInt())
+            }
+
+            emitTopSitesCountFact(1)
+
+            assertEquals(2, facts.size)
+            facts[1].apply {
+                assertEquals(Component.FEATURE_TOP_SITES, component)
+                assertEquals(Action.INTERACTION, action)
+                assertEquals(TopSitesFacts.Items.COUNT, item)
+                assertEquals(1, value?.toInt())
+            }
+        }
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/presenter/DefaultTopSitesPresenterTest.kt b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/presenter/DefaultTopSitesPresenterTest.kt
new file mode 100644
index 0000000000..eb4a14ac24
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/test/java/mozilla/components/feature/top/sites/presenter/DefaultTopSitesPresenterTest.kt
@@ -0,0 +1,37 @@
+/* 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 mozilla.components.feature.top.sites.presenter
+
+import mozilla.components.feature.top.sites.DefaultTopSitesStorage
+import mozilla.components.feature.top.sites.TopSitesConfig
+import mozilla.components.feature.top.sites.view.TopSitesView
+import mozilla.components.support.test.mock
+import org.junit.Test
+import org.mockito.Mockito.spy
+import org.mockito.Mockito.verify
+
+class DefaultTopSitesPresenterTest {
+
+    private val view: TopSitesView = mock()
+    private val storage: DefaultTopSitesStorage = mock()
+    private val config: () -> TopSitesConfig = mock()
+    private val presenter: DefaultTopSitesPresenter =
+        spy(DefaultTopSitesPresenter(view, storage, config))
+
+    @Test
+    fun start() {
+        presenter.start()
+
+        verify(presenter).onStorageUpdated()
+        verify(storage).register(presenter)
+    }
+
+    @Test
+    fun stop() {
+        presenter.stop()
+
+        verify(storage).unregister(presenter)
+    }
+}
diff --git a/mobile/android/android-components/components/feature/top-sites/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker b/mobile/android/android-components/components/feature/top-sites/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker
new file mode 100644
index 0000000000..cf1c399ea8
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker
@@ -0,0 +1,2 @@
+mock-maker-inline
+// This allows mocking final classes (classes are final by default in Kotlin)
diff --git a/mobile/android/android-components/components/feature/top-sites/src/test/resources/robolectric.properties b/mobile/android/android-components/components/feature/top-sites/src/test/resources/robolectric.properties
new file mode 100644
index 0000000000..932b01b9eb
--- /dev/null
+++ b/mobile/android/android-components/components/feature/top-sites/src/test/resources/robolectric.properties
@@ -0,0 +1 @@
+sdk=28