diff --git a/app/src/androidTestKiwix/java/org/kiwix/kiwixmobile/utils/files/FileUtilsTest.java b/app/src/androidTestKiwix/java/org/kiwix/kiwixmobile/utils/files/FileUtilsTest.java
new file mode 100644
index 000000000..74cbaf00a
--- /dev/null
+++ b/app/src/androidTestKiwix/java/org/kiwix/kiwixmobile/utils/files/FileUtilsTest.java
@@ -0,0 +1,83 @@
+/*
+ * Kiwix Android
+ * Copyright (C) 2018  Kiwix <android.kiwix.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.kiwix.kiwixmobile.utils.files;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.support.test.InstrumentationRegistry;
+import java.io.File;
+import java.util.List;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.kiwix.kiwixmobile.library.entity.LibraryNetworkEntity.Book;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.mockito.junit.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class FileUtilsTest {
+
+  private boolean mockInitialized = false;
+  private Context context;
+  //private FileUtils fileUtils;
+
+  @Before
+  public void executeBefore(){
+    if (!mockInitialized) {
+      MockitoAnnotations.initMocks(this);
+      mockInitialized = true;
+    }
+    context = InstrumentationRegistry.getTargetContext();
+    //fileUtils = new FileUtils();
+  }
+
+  @Test
+  public void testGetAllZimParts(){
+    String testId = "8ce5775a-10a9-bbf3-178a-9df69f23263c";
+    String fileName = context.getFilesDir().getAbsolutePath() + File.separator + testId;
+    List<File> files;
+
+    //Test-1 (filename ends with .zim)
+    Book book1 = new Book();
+    book1.file = new File(fileName + ".zim");
+    files = FileUtils.getAllZimParts(book1);
+    assertEquals(1, files.size());
+    assertEquals(book1.file.getPath() + ".part", files.get(0).getPath());
+
+    //Test-2 (filename ends with .zim.part)
+    Book book2 = new Book();
+    book2.file = new File(fileName + ".zim.part");
+    files = FileUtils.getAllZimParts(book2);
+    assertEquals(1, files.size());
+    assertEquals(book2.file.getPath() + ".part", files.get(0).getPath());
+
+    //Test-3 (filename ends with .zimXX)
+    Book book3 = new Book();
+    book3.file = new File(fileName + ".zimab");
+    files = FileUtils.getAllZimParts(book3);
+    assertEquals(0, files.size());
+
+    //TODO : find a way to stub the file.exist() method and add more tests
+  }
+
+}
\ No newline at end of file
diff --git a/app/src/main/java/org/kiwix/kiwixmobile/utils/files/FileUtils.java b/app/src/main/java/org/kiwix/kiwixmobile/utils/files/FileUtils.java
index 69e07aafe..e65fbb485 100644
--- a/app/src/main/java/org/kiwix/kiwixmobile/utils/files/FileUtils.java
+++ b/app/src/main/java/org/kiwix/kiwixmobile/utils/files/FileUtils.java
@@ -211,7 +211,7 @@ public class FileUtils {
     return readCsv(content);
   }
 
-  private static List<File> getAllZimParts(Book book) {
+  public static List<File> getAllZimParts(Book book) {
     List<File> files = new ArrayList<>();
     if(book.file.getPath().endsWith(".zim") || book.file.getPath().endsWith(".zim.part")) {
       if(book.file.exists()) {