9 files changed, 373 insertions, 4 deletions

diff --git a/core/build.gradle b/core/build.gradle
index fe130063e..96f0f7f04 100644
--- a/core/build.gradle
+++ b/core/build.gradle
@@ -52,6 +52,12 @@ android {
             dimension "market"
         }
     }
+
+    testOptions {
+        unitTests {
+            includeAndroidResources = true
+        }
+    }
 }
 
 dependencies {
@@ -94,7 +100,9 @@ dependencies {
 
     testImplementation "org.awaitility:awaitility:$awaitilityVersion"
     testImplementation 'junit:junit:4.13'
-    testImplementation 'org.mockito:mockito-core:1.10.19'
+    testImplementation 'org.mockito:mockito-inline:3.5.13'
+    testImplementation 'org.robolectric:robolectric:4.3.1'
+    testImplementation 'javax.inject:javax.inject:1'
     androidTestImplementation "com.jayway.android.robotium:robotium-solo:$robotiumSoloVersion"
     androidTestImplementation "androidx.test.espresso:espresso-core:$espressoVersion"
     androidTestImplementation "androidx.test:runner:$runnerVersion"
diff --git a/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java b/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java
index 142763d75..4c594783a 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/storage/PodDBAdapter.java
@@ -358,6 +358,21 @@ public class PodDBAdapter {
         // do nothing
     }
 
+    /**
+     * <p>Resets all database connections to ensure new database connections for
+     * the next test case. Call method only for unit tests.</p>
+     *
+     * <p>That's a workaround for a Robolectric issue in ShadowSQLiteConnection
+     * that leads to an error <tt>IllegalStateException: Illegal connection
+     * pointer</tt> if several threads try to use the same database connection.
+     * For more information see
+     * <a href="https://github.com/robolectric/robolectric/issues/1890">robolectric/robolectric#1890</a>.</p>
+     */
+    public static void tearDownTests() {
+        db = null;
+        SingletonHolder.dbHelper.close();
+    }
+
     public static boolean deleteDatabase() {
         PodDBAdapter adapter = getInstance();
         adapter.open();
diff --git a/core/src/test/assets/local-feed1/track1.mp3 b/core/src/test/assets/local-feed1/track1.mp3
new file mode 100644
index 000000000..b1f993c3f
--- /dev/null
+++ b/core/src/test/assets/local-feed1/track1.mp3
diff --git a/core/src/test/assets/local-feed2/folder.png b/core/src/test/assets/local-feed2/folder.png
new file mode 100644
index 000000000..9e522a986
--- /dev/null
+++ b/core/src/test/assets/local-feed2/folder.png
diff --git a/core/src/test/assets/local-feed2/track1.mp3 b/core/src/test/assets/local-feed2/track1.mp3
new file mode 100644
index 000000000..b1f993c3f
--- /dev/null
+++ b/core/src/test/assets/local-feed2/track1.mp3
diff --git a/core/src/test/assets/local-feed2/track2.mp3 b/core/src/test/assets/local-feed2/track2.mp3
new file mode 100644
index 000000000..310cddd6b
--- /dev/null
+++ b/core/src/test/assets/local-feed2/track2.mp3
diff --git a/core/src/test/java/androidx/documentfile/provider/AssetsDocumentFile.java b/core/src/test/java/androidx/documentfile/provider/AssetsDocumentFile.java
new file mode 100644
index 000000000..8a8205c10
--- /dev/null
+++ b/core/src/test/java/androidx/documentfile/provider/AssetsDocumentFile.java
@@ -0,0 +1,138 @@
+package androidx.documentfile.provider;
+
+import android.content.res.AssetManager;
+import android.net.Uri;
+import android.webkit.MimeTypeMap;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import java.io.IOException;
+
+/**
+ * <p>Wraps an Android assets file or folder as a DocumentFile object.</p>
+ *
+ * <p>This is used to emulate access to the external storage.</p>
+ */
+public class AssetsDocumentFile extends DocumentFile {
+
+    /**
+     * Absolute file path in the assets folder.
+     */
+    @NonNull
+    private final String fileName;
+
+    @NonNull
+    private final AssetManager assetManager;
+
+    public AssetsDocumentFile(@NonNull String fileName, @NonNull AssetManager assetManager) {
+        super(null);
+        this.fileName = fileName;
+        this.assetManager = assetManager;
+    }
+
+    @Nullable
+    @Override
+    public DocumentFile createFile(@NonNull String mimeType, @NonNull String displayName) {
+        return null;
+    }
+
+    @Nullable
+    @Override
+    public DocumentFile createDirectory(@NonNull String displayName) {
+        return null;
+    }
+
+    @NonNull
+    @Override
+    public Uri getUri() {
+        return Uri.parse(fileName);
+    }
+
+    @Nullable
+    @Override
+    public String getName() {
+        int pos = fileName.indexOf('/');
+        if (pos >= 0) {
+            return fileName.substring(pos + 1);
+        } else {
+            return fileName;
+        }
+    }
+
+    @Nullable
+    @Override
+    public String getType() {
+        String extension = MimeTypeMap.getFileExtensionFromUrl(fileName);
+        return MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
+    }
+
+    @Override
+    public boolean isDirectory() {
+        return false;
+    }
+
+    @Override
+    public boolean isFile() {
+        return true;
+    }
+
+    @Override
+    public boolean isVirtual() {
+        return false;
+    }
+
+    @Override
+    public long lastModified() {
+        return 0;
+    }
+
+    @Override
+    public long length() {
+        return 0;
+    }
+
+    @Override
+    public boolean canRead() {
+        return true;
+    }
+
+    @Override
+    public boolean canWrite() {
+        return false;
+    }
+
+    @Override
+    public boolean delete() {
+        return false;
+    }
+
+    @Override
+    public boolean exists() {
+        return true;
+    }
+
+    @NonNull
+    @Override
+    public DocumentFile[] listFiles() {
+        try {
+            String[] files = assetManager.list(fileName);
+            if (files == null) {
+                return new DocumentFile[0];
+            }
+            DocumentFile[] result = new DocumentFile[files.length];
+            for (int i = 0; i < files.length; i++) {
+                String subFileName = fileName + '/' + files[i];
+                result[i] = new AssetsDocumentFile(subFileName, assetManager);
+            }
+            return result;
+        } catch (IOException e) {
+            return new DocumentFile[0];
+        }
+    }
+
+    @Override
+    public boolean renameTo(@NonNull String displayName) {
+        return false;
+    }
+}
diff --git a/core/src/test/java/de/danoeh/antennapod/core/feed/LocalFeedUpdaterTest.java b/core/src/test/java/de/danoeh/antennapod/core/feed/LocalFeedUpdaterTest.java
new file mode 100644
index 000000000..90bf59e92
--- /dev/null
+++ b/core/src/test/java/de/danoeh/antennapod/core/feed/LocalFeedUpdaterTest.java
@@ -0,0 +1,208 @@
+package de.danoeh.antennapod.core.feed;
+
+import android.app.Application;
+import android.content.Context;
+import android.media.MediaMetadataRetriever;
+import android.webkit.MimeTypeMap;
+
+import androidx.annotation.NonNull;
+import androidx.documentfile.provider.AssetsDocumentFile;
+import androidx.documentfile.provider.DocumentFile;
+import androidx.test.platform.app.InstrumentationRegistry;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.MockedStatic;
+import org.mockito.Mockito;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.shadows.ShadowMediaMetadataRetriever;
+
+import java.io.IOException;
+import java.util.List;
+
+import de.danoeh.antennapod.core.ApplicationCallbacks;
+import de.danoeh.antennapod.core.ClientConfig;
+import de.danoeh.antennapod.core.R;
+import de.danoeh.antennapod.core.preferences.UserPreferences;
+import de.danoeh.antennapod.core.storage.DBReader;
+import de.danoeh.antennapod.core.storage.PodDBAdapter;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static org.robolectric.Shadows.shadowOf;
+
+/**
+ * Test local feeds handling in class LocalFeedUpdater.
+ */
+@RunWith(RobolectricTestRunner.class)
+public class LocalFeedUpdaterTest {
+
+    /**
+     * URL to locate the local feed media files on the external storage (SD card).
+     * The exact URL doesn't matter here as access to external storage is mocked
+     * (seems not to be supported by Robolectric).
+     */
+    private static final String FEED_URL =
+            "content://com.android.externalstorage.documents/tree/primary%3ADownload%2Flocal-feed";
+    private static final String LOCAL_FEED_DIR1 = "local-feed1";
+    private static final String LOCAL_FEED_DIR2 = "local-feed2";
+
+    private Context context;
+
+    @Before
+    public void setUp() throws Exception {
+        // Initialize environment
+        context = InstrumentationRegistry.getInstrumentation().getContext();
+        UserPreferences.init(context);
+
+        Application app = (Application) context;
+        ClientConfig.applicationCallbacks = mock(ApplicationCallbacks.class);
+        when(ClientConfig.applicationCallbacks.getApplicationInstance()).thenReturn(app);
+
+        // Initialize database
+        PodDBAdapter.init(context);
+        PodDBAdapter.deleteDatabase();
+        PodDBAdapter adapter = PodDBAdapter.getInstance();
+        adapter.open();
+        adapter.close();
+
+        mapDummyMetadata(LOCAL_FEED_DIR1);
+        mapDummyMetadata(LOCAL_FEED_DIR2);
+        shadowOf(MimeTypeMap.getSingleton()).addExtensionMimeTypMapping("mp3", "audio/mp3");
+    }
+
+    @After
+    public void tearDown() {
+        PodDBAdapter.tearDownTests();
+    }
+
+    /**
+     * Test adding a new local feed.
+     */
+    @Test
+    public void testUpdateFeed_AddNewFeed() {
+        // check for empty database
+        List<Feed> feedListBefore = DBReader.getFeedList();
+        assertTrue(feedListBefore.isEmpty());
+
+        callUpdateFeed(LOCAL_FEED_DIR2);
+
+        // verify new feed in database
+        verifySingleFeedInDatabaseAndItemCount(2);
+        Feed feedAfter = verifySingleFeedInDatabase();
+        assertEquals(FEED_URL, feedAfter.getDownload_url());
+    }
+
+    /**
+     * Test adding further items to an existing local feed.
+     */
+    @Test
+    public void testUpdateFeed_AddMoreItems() {
+        // add local feed with 1 item (localFeedDir1)
+        callUpdateFeed(LOCAL_FEED_DIR1);
+
+        // now add another item (by changing to local feed folder localFeedDir2)
+        callUpdateFeed(LOCAL_FEED_DIR2);
+
+        verifySingleFeedInDatabaseAndItemCount(2);
+    }
+
+    /**
+     * Test removing items from an existing local feed without a corresponding media file.
+     */
+    @Test
+    public void testUpdateFeed_RemoveItems() {
+        // add local feed with 2 items (localFeedDir1)
+        callUpdateFeed(LOCAL_FEED_DIR2);
+
+        // now remove an item (by changing to local feed folder localFeedDir1)
+        callUpdateFeed(LOCAL_FEED_DIR1);
+
+        verifySingleFeedInDatabaseAndItemCount(1);
+    }
+
+    /**
+     * Test feed icon defined in the local feed media folder.
+     */
+    @Test
+    public void testUpdateFeed_FeedIconFromFolder() {
+        callUpdateFeed(LOCAL_FEED_DIR2);
+
+        Feed feedAfter = verifySingleFeedInDatabase();
+        assertTrue(feedAfter.getImageUrl().contains("local-feed2/folder.png"));
+    }
+
+    /**
+     * Test default feed icon if there is no matching file in the local feed media folder.
+     */
+    @Test
+    public void testUpdateFeed_FeedIconDefault() {
+        callUpdateFeed(LOCAL_FEED_DIR1);
+
+        Feed feedAfter = verifySingleFeedInDatabase();
+        String resourceEntryName = context.getResources().getResourceEntryName(R.raw.local_feed_default_icon);
+        assertTrue(feedAfter.getImageUrl().contains(resourceEntryName));
+    }
+
+    /**
+     * Fill ShadowMediaMetadataRetriever with dummy duration and title.
+     *
+     * @param localFeedDir assets local feed folder with media files
+     */
+    private void mapDummyMetadata(@NonNull String localFeedDir) throws IOException {
+        String[] fileNames = context.getAssets().list(localFeedDir);
+        for (String fileName : fileNames) {
+            String path = localFeedDir + '/' + fileName;
+            ShadowMediaMetadataRetriever.addMetadata(path,
+                    MediaMetadataRetriever.METADATA_KEY_DURATION, "10");
+            ShadowMediaMetadataRetriever.addMetadata(path,
+                    MediaMetadataRetriever.METADATA_KEY_TITLE, fileName);
+        }
+
+    }
+
+    /**
+     * Calls the method {@link LocalFeedUpdater#updateFeed(Feed, Context)} with
+     * the given local feed folder.
+     *
+     * @param localFeedDir assets local feed folder with media files
+     */
+    private void callUpdateFeed(@NonNull String localFeedDir) {
+        DocumentFile documentFile = new AssetsDocumentFile(localFeedDir, context.getAssets());
+        try (MockedStatic<DocumentFile> dfMock = Mockito.mockStatic(DocumentFile.class)) {
+            // mock external storage
+            dfMock.when(() -> DocumentFile.fromTreeUri(any(), any())).thenReturn(documentFile);
+
+            // call method to test
+            Feed feed = new Feed(FEED_URL, null);
+            LocalFeedUpdater.updateFeed(feed, context);
+        }
+    }
+
+    /**
+     * Verify that the database contains exactly one feed and return that feed.
+     */
+    @NonNull
+    private static Feed verifySingleFeedInDatabase() {
+        List<Feed> feedListAfter = DBReader.getFeedList();
+        assertEquals(1, feedListAfter.size());
+        return feedListAfter.get(0);
+    }
+
+    /**
+     * Verify that the database contains exactly one feed and the number of
+     * items in the feed.
+     *
+     * @param expectedItemCount expected number of items in the feed
+     */
+    private static void verifySingleFeedInDatabaseAndItemCount(int expectedItemCount) {
+        Feed feed = verifySingleFeedInDatabase();
+        List<FeedItem> feedItems = DBReader.getFeedItemList(feed);
+        assertEquals(expectedItemCount, feedItems.size());
+    }
+}
diff --git a/core/src/test/java/de/danoeh/antennapod/core/storage/ItemEnqueuePositionCalculatorTest.java b/core/src/test/java/de/danoeh/antennapod/core/storage/ItemEnqueuePositionCalculatorTest.java
index ed7d2fa75..6c5a9daf1 100644
--- a/core/src/test/java/de/danoeh/antennapod/core/storage/ItemEnqueuePositionCalculatorTest.java
+++ b/core/src/test/java/de/danoeh/antennapod/core/storage/ItemEnqueuePositionCalculatorTest.java
@@ -32,7 +32,7 @@ import static java.util.Collections.emptyList;
 import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.stub;
+import static org.mockito.Mockito.when;
 
 public class ItemEnqueuePositionCalculatorTest {
 
@@ -189,7 +189,7 @@ public class ItemEnqueuePositionCalculatorTest {
             //
             ItemEnqueuePositionCalculator calculator = new ItemEnqueuePositionCalculator(options);
             DownloadStateProvider stubDownloadStateProvider = mock(DownloadStateProvider.class);
-            stub(stubDownloadStateProvider.isDownloadingFile(any(FeedMedia.class))).toReturn(false);
+            when(stubDownloadStateProvider.isDownloadingFile(any(FeedMedia.class))).thenReturn(false);
             calculator.downloadStateProvider = stubDownloadStateProvider;
 
             // Setup initial data
@@ -232,7 +232,7 @@ public class ItemEnqueuePositionCalculatorTest {
 
         private static FeedItem setAsDownloading(FeedItem item, DownloadStateProvider stubDownloadStateProvider,
                                                  boolean isDownloading) {
-            stub(stubDownloadStateProvider.isDownloadingFile(item.getMedia())).toReturn(isDownloading);
+            when(stubDownloadStateProvider.isDownloadingFile(item.getMedia())).thenReturn(isDownloading);
             return item;
         }