5161: Fix repeating images in peer review (#5170)

* fix API call to fetch the latest changes

* add database table to keep a track of reviewed and skipped images

* fix repeating reviewed or skipped images

* add removed newline again

* add necessary comments

* change from timber.e to timber.i in case there is no exception

* reintroduce the parameter rctag in the API URL

* modify API URL to retrieve latest uploads

* remove unused imports and code

* modify ReviewHelperTest and add new unit tests

* modify tests in ReviewHelperTest.kt

* add comments about the value of gcmlimit

app/src/androidTest/java/fr/free/nrw/commons/ReviewDaoTest.java

@@ -0,0 +1,74 @@
+package fr.free.nrw.commons;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import android.content.Context;
+import androidx.room.Room;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import fr.free.nrw.commons.db.AppDatabase;
+import fr.free.nrw.commons.review.ReviewDao;
+import fr.free.nrw.commons.review.ReviewEntity;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+public class ReviewDaoTest {
+
+    private ReviewDao reviewDao;
+    private AppDatabase database;
+
+    /**
+     * Set up the application database
+     */
+    @Before
+    public void createDb() {
+        Context context = ApplicationProvider.getApplicationContext();
+        database = Room.inMemoryDatabaseBuilder(
+                context, AppDatabase.class)
+            .allowMainThreadQueries()
+            .build();
+        reviewDao = database.ReviewDao();
+    }
+
+    /**
+     * Close the database
+     */
+    @After
+    public void closeDb() {
+        database.close();
+    }
+
+    /**
+     * Test insertion
+     * Also checks isReviewedAlready():
+     * Case 1: When image has been reviewed/skipped by the user
+     */
+    @Test
+    public void insert() {
+        // Insert data
+        String imageId = "1234";
+        ReviewEntity reviewEntity = new ReviewEntity(imageId);
+        reviewDao.insert(reviewEntity);
+
+        // Check insertion
+        // Covers the case where the image exists in the database
+        // And isReviewedAlready() returns true
+        Boolean isInserted = reviewDao.isReviewedAlready(imageId);
+        assertThat(isInserted, equalTo(true));
+    }
+
+    /**
+     * Test review status of the image
+     * Case 2: When image has not been reviewed/skipped
+     */
+    @Test
+    public void isReviewedAlready(){
+        String imageId = "5856";
+        Boolean isInserted = reviewDao.isReviewedAlready(imageId);
+        assertThat(isInserted, equalTo(false));
+    }
+}