diff --git a/app/src/androidTest/java/org/kiwix/kiwixmobile/utils/files/FileUtilsInstrumentationTest.kt b/app/src/androidTest/java/org/kiwix/kiwixmobile/utils/files/FileUtilsInstrumentationTest.kt
index 56c863241..bbb899772 100644
--- a/app/src/androidTest/java/org/kiwix/kiwixmobile/utils/files/FileUtilsInstrumentationTest.kt
+++ b/app/src/androidTest/java/org/kiwix/kiwixmobile/utils/files/FileUtilsInstrumentationTest.kt
@@ -23,9 +23,11 @@ import org.junit.After
 import org.junit.Assert
 import org.junit.Before
 import org.junit.Test
+import org.junit.jupiter.api.Assertions
 import org.kiwix.kiwixmobile.core.utils.files.FileUtils.getAllZimParts
 import org.kiwix.kiwixmobile.core.utils.files.FileUtils.hasPart
 import org.kiwix.kiwixmobile.core.entity.LibraryNetworkEntity
+import org.kiwix.kiwixmobile.core.utils.files.FileUtils
 import java.io.File
 import java.io.IOException
 import java.util.Random
@@ -199,4 +201,50 @@ class FileUtilsInstrumentationTest {
       it.delete()
     }
   }
+
+  @Test
+  fun testDecodeFileName() {
+    val dummyUrlArray = listOf(
+      DummyUrlData(
+        "https://kiwix.org/contributors/contributors_list.pdf",
+        "contributors_list.pdf"
+      ),
+      DummyUrlData(
+        "https://kiwix.org/contributors/",
+        null
+      ),
+      DummyUrlData(
+        "android_tutorials.pdf",
+        null
+      ),
+      DummyUrlData(
+        null,
+        null
+      ),
+      DummyUrlData(
+        "/html/images/test.png",
+        "test.png"
+      ),
+      DummyUrlData(
+        "/html/images/",
+        null
+      ),
+      DummyUrlData(
+        "https://kiwix.org/contributors/images/wikipedia.png",
+        "wikipedia.png"
+      ),
+      DummyUrlData(
+        "https://kiwix.org/contributors/images/wikipedia",
+        null
+      )
+    )
+    dummyUrlArray.forEach {
+      Assertions.assertEquals(
+        FileUtils.getDecodedFileName(it.url),
+        it.expectedFileName
+      )
+    }
+  }
+
+  data class DummyUrlData(val url: String?, val expectedFileName: String?)
 }
diff --git a/buildSrc/src/main/kotlin/Versions.kt b/buildSrc/src/main/kotlin/Versions.kt
index b19dcf2ce..8c3d0c458 100644
--- a/buildSrc/src/main/kotlin/Versions.kt
+++ b/buildSrc/src/main/kotlin/Versions.kt
@@ -42,7 +42,7 @@ object Versions {
 
   const val io_objectbox: String = "3.5.0"
 
-  const val io_mockk: String = "1.12.0"
+  const val io_mockk: String = "1.13.4"
 
   const val android_arch_lifecycle_extensions: String = "1.1.1"
 
diff --git a/core/src/main/java/org/kiwix/kiwixmobile/core/utils/NetworkUtils.kt b/core/src/main/java/org/kiwix/kiwixmobile/core/utils/NetworkUtils.kt
index f0fee1dd0..7af62299c 100644
--- a/core/src/main/java/org/kiwix/kiwixmobile/core/utils/NetworkUtils.kt
+++ b/core/src/main/java/org/kiwix/kiwixmobile/core/utils/NetworkUtils.kt
@@ -22,6 +22,7 @@ import android.net.ConnectivityManager
 import android.net.NetworkInfo
 import android.os.Build
 import android.util.Log
+import androidx.annotation.VisibleForTesting
 import org.kiwix.kiwixmobile.core.R
 import java.lang.Exception
 import java.util.UUID
@@ -41,6 +42,9 @@ object NetworkUtils {
   fun isNetworkConnectionOK(networkInfo: NetworkInfo): Boolean =
     networkInfo.state == NetworkInfo.State.CONNECTED
 
+  @VisibleForTesting
+  internal var sdkVersionForTesting = Build.VERSION.SDK_INT
+
   /**
    * check if network of type WIFI is connected
    *
@@ -52,7 +56,7 @@ object NetworkUtils {
   fun isWiFi(context: Context): Boolean {
     val connectivity = context
       .getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
-    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+    return if (sdkVersionForTesting >= Build.VERSION_CODES.M) {
       val networkInfo = connectivity.activeNetworkInfo ?: return false
       networkInfo.type == ConnectivityManager.TYPE_WIFI && networkInfo.isConnected
     } else {
diff --git a/core/src/test/java/org/kiwix/kiwixmobile/core/utils/NetworkUtilsTest.kt b/core/src/test/java/org/kiwix/kiwixmobile/core/utils/NetworkUtilsTest.kt
index aca82a2f9..fd098a0e6 100644
--- a/core/src/test/java/org/kiwix/kiwixmobile/core/utils/NetworkUtilsTest.kt
+++ b/core/src/test/java/org/kiwix/kiwixmobile/core/utils/NetworkUtilsTest.kt
@@ -21,8 +21,6 @@ package org.kiwix.kiwixmobile.core.utils
 import android.content.Context
 import android.net.ConnectivityManager
 import android.net.NetworkInfo
-import android.os.Build
-import android.util.Log
 import io.mockk.every
 import io.mockk.mockk
 import io.mockk.verify
@@ -31,8 +29,6 @@ import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
 import org.junit.jupiter.api.Test
 import org.kiwix.kiwixmobile.core.R
-import java.lang.reflect.Field
-import java.lang.reflect.Modifier
 import java.util.regex.Pattern
 
 class NetworkUtilsTest {
@@ -79,11 +75,7 @@ class NetworkUtilsTest {
     every { (connectivity.activeNetworkInfo) } returns networkInfo
 
     // SDK >= 23
-    try {
-      setSDKVersion(Build.VERSION::class.java.getField("SDK_INT"), 23)
-    } catch (e: Exception) {
-      Log.d("NetworkUtilsTest", "Unable to set Build SDK Version")
-    }
+    NetworkUtils.sdkVersionForTesting = 23
 
     // on Mobile Data
     every { (networkInfo.type) } returns ConnectivityManager.TYPE_MOBILE
@@ -110,11 +102,7 @@ class NetworkUtilsTest {
     verify(exactly = 0) { connectivity.getNetworkInfo(ConnectivityManager.TYPE_WIFI) }
 
     // SDK < 23
-    try {
-      setSDKVersion(Build.VERSION::class.java.getField("SDK_INT"), 22)
-    } catch (e: Exception) {
-      Log.d("NetworkUtilsTest", "Unable to set Build SDK Version")
-    }
+    NetworkUtils.sdkVersionForTesting = 22
 
     // WIFI connected
     every { (connectivity.getNetworkInfo(ConnectivityManager.TYPE_WIFI)) } returns networkInfo
@@ -236,17 +224,4 @@ class NetworkUtilsTest {
       )
     )
   }
-
-  // Sets the Build SDK version
-  @Throws(Exception::class)
-  private fun setSDKVersion(
-    field: Field,
-    newValue: Any
-  ) {
-    field.isAccessible = true
-    val modifiersField = Field::class.java.getDeclaredField("modifiers")
-    modifiersField.isAccessible = true
-    modifiersField.setInt(field, field.modifiers and Modifier.FINAL.inv())
-    field.set(null, newValue)
-  }
 }
diff --git a/app/src/androidTest/java/org/kiwix/kiwixmobile/utils/files/FileUtilsTest.kt b/core/src/test/java/org/kiwix/kiwixmobile/core/utils/files/FileUtilsTest.kt
similarity index 61%
rename from app/src/androidTest/java/org/kiwix/kiwixmobile/utils/files/FileUtilsTest.kt
rename to core/src/test/java/org/kiwix/kiwixmobile/core/utils/files/FileUtilsTest.kt
index 38924553c..e271728a8 100644
--- a/app/src/androidTest/java/org/kiwix/kiwixmobile/utils/files/FileUtilsTest.kt
+++ b/core/src/test/java/org/kiwix/kiwixmobile/core/utils/files/FileUtilsTest.kt
@@ -16,42 +16,25 @@
  *
  */
 
-package org.kiwix.kiwixmobile.utils.files
+package org.kiwix.kiwixmobile.core.utils.files
 
-import androidx.core.content.edit
-import androidx.preference.PreferenceManager
-import androidx.test.platform.app.InstrumentationRegistry
-import androidx.test.uiautomator.UiDevice
 import io.mockk.clearMocks
 import io.mockk.every
 import io.mockk.mockk
-import org.junit.Before
-import org.junit.Test
+import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.BeforeEach
-import org.kiwix.kiwixmobile.BaseActivityTest
 import org.kiwix.kiwixmobile.core.CoreApp
 import org.kiwix.kiwixmobile.core.entity.LibraryNetworkEntity.Book
-import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
-import org.kiwix.kiwixmobile.core.utils.files.FileUtils
 import java.io.File
 
-class FileUtilsTest : BaseActivityTest() {
+class FileUtilsTest {
 
   private val mockFile: File = mockk()
   private val testBook = Book().apply { file = mockFile }
   private val testId = "8ce5775a-10a9-bbf3-178a-9df69f23263c"
   private val fileName = "/data/user/0/org.kiwix.kiwixmobile/files${File.separator}$testId"
 
-  @Before
-  override fun waitForIdle() {
-    UiDevice.getInstance(InstrumentationRegistry.getInstrumentation()).waitForIdle()
-    PreferenceManager.getDefaultSharedPreferences(context).edit {
-      putBoolean(SharedPreferenceUtil.PREF_SHOW_INTRO, false)
-      putBoolean(SharedPreferenceUtil.PREF_WIFI_ONLY, false)
-    }
-  }
-
   @BeforeEach
   fun init() {
     clearMocks(mockFile)
@@ -117,50 +100,4 @@ class FileUtilsTest : BaseActivityTest() {
     every { mockFile.path } returns "$fileName$extension"
     every { mockFile.exists() } returns fileExists
   }
-
-  @Test
-  fun testDecodeFileName() {
-    val dummyUrlArray = listOf(
-      DummyUrlData(
-        "https://kiwix.org/contributors/contributors_list.pdf",
-        "contributors_list.pdf"
-      ),
-      DummyUrlData(
-        "https://kiwix.org/contributors/",
-        null
-      ),
-      DummyUrlData(
-        "android_tutorials.pdf",
-        null
-      ),
-      DummyUrlData(
-        null,
-        null
-      ),
-      DummyUrlData(
-        "/html/images/test.png",
-        "test.png"
-      ),
-      DummyUrlData(
-        "/html/images/",
-        null
-      ),
-      DummyUrlData(
-        "https://kiwix.org/contributors/images/wikipedia.png",
-        "wikipedia.png"
-      ),
-      DummyUrlData(
-        "https://kiwix.org/contributors/images/wikipedia",
-        null
-      )
-    )
-    dummyUrlArray.forEach {
-      assertEquals(
-        FileUtils.getDecodedFileName(it.url),
-        it.expectedFileName
-      )
-    }
-  }
-
-  data class DummyUrlData(val url: String?, val expectedFileName: String?)
 }