Error on opening a split zim file on external storage.

 * Added test cases for testing that the ZimFileReader can open the splitted zim file or not.

app/src/androidTest/java/org/kiwix/kiwixmobile/page/history/NavigationHistoryRobot.kt

@@ -70,6 +70,17 @@ class NavigationHistoryRobot : BaseRobot() {
       .perform(webClick())
   }
 
+  fun assertZimFileLoaded() {
+    pauseForBetterTestPerformance()
+    onWebView()
+      .withElement(
+        findElement(
+          Locator.XPATH,
+          "//*[contains(text(), 'Android_(operating_system)')]"
+        )
+      )
+  }
+
   fun longClickOnBackwardButton() {
     pauseForBetterTestPerformance()
     longClickOn(ViewId(R.id.bottom_toolbar_arrow_back))

app/src/androidTest/java/org/kiwix/kiwixmobile/reader/ZimFileReaderWithSplittedZimFileTest.kt

@@ -0,0 +1,148 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2024 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.reader
+
+import androidx.core.content.ContextCompat
+import androidx.core.content.edit
+import androidx.core.net.toUri
+import androidx.lifecycle.Lifecycle
+import androidx.preference.PreferenceManager
+import androidx.test.core.app.ActivityScenario
+import androidx.test.internal.runner.junit4.statement.UiThreadStatement
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.uiautomator.UiDevice
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import org.junit.jupiter.api.fail
+import org.kiwix.kiwixmobile.BaseActivityTest
+import org.kiwix.kiwixmobile.R
+import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
+import org.kiwix.kiwixmobile.main.KiwixMainActivity
+import org.kiwix.kiwixmobile.nav.destination.library.LocalLibraryFragmentDirections
+import org.kiwix.kiwixmobile.page.history.navigationHistory
+import org.kiwix.kiwixmobile.testutils.RetryRule
+import org.kiwix.kiwixmobile.testutils.TestUtils
+import java.io.File
+import java.io.FileOutputStream
+import java.io.OutputStream
+
+class ZimFileReaderWithSplittedZimFileTest : BaseActivityTest() {
+
+  @Rule
+  @JvmField
+  var retryRule = RetryRule()
+
+  private lateinit var kiwixMainActivity: KiwixMainActivity
+
+  @Before
+  override fun waitForIdle() {
+    UiDevice.getInstance(InstrumentationRegistry.getInstrumentation()).apply {
+      if (TestUtils.isSystemUINotRespondingDialogVisible(this)) {
+        TestUtils.closeSystemDialogs(context, this)
+      }
+      waitForIdle()
+    }
+    PreferenceManager.getDefaultSharedPreferences(context).edit {
+      putBoolean(SharedPreferenceUtil.PREF_SHOW_INTRO, false)
+      putBoolean(SharedPreferenceUtil.PREF_WIFI_ONLY, false)
+      putBoolean(SharedPreferenceUtil.PREF_PLAY_STORE_RESTRICTION, false)
+    }
+    activityScenario = ActivityScenario.launch(KiwixMainActivity::class.java).apply {
+      moveToState(Lifecycle.State.RESUMED)
+    }
+  }
+
+  @Test
+  fun testZimFileReaderWithSplittedZimFile() {
+    activityScenario.onActivity {
+      kiwixMainActivity = it
+      kiwixMainActivity.navigate(R.id.libraryFragment)
+    }
+    createAndGetSplitedZimFile()?.let {
+      UiThreadStatement.runOnUiThread {
+        kiwixMainActivity.navigate(
+          LocalLibraryFragmentDirections.actionNavigationLibraryToNavigationReader()
+            .apply { zimFileUri = it.toUri().toString() }
+        )
+      }
+
+      navigationHistory {
+        checkZimFileLoadedSuccessful(R.id.readerFragment)
+        assertZimFileLoaded() // check if the zim file successfully loaded
+        clickOnAndroidArticle()
+      }
+    } ?: kotlin.run {
+      // error in creating the zim file chunk
+      fail("Couldn't create the zim file chunk")
+    }
+  }
+
+  private fun createAndGetSplitedZimFile(): File? {
+    val loadFileStream =
+      EncodedUrlTest::class.java.classLoader.getResourceAsStream("testzim.zim")
+    val storageDir = ContextCompat.getExternalFilesDirs(context, null)[0]
+
+    // Delete existing parts if they exist
+    (1..3)
+      .asSequence()
+      .map { File(storageDir, "testzim.zima${('a' + it - 1).toChar()}") }
+      .filter(File::exists)
+      .forEach(File::delete)
+
+    // Calculate the size of each part
+    val totalFileSize = loadFileStream.available().toLong()
+    val partSize = totalFileSize / 3 // convert into 3 parts
+    var partNumber = 1
+
+    // Read the input stream in chunks and write to smaller files
+    loadFileStream.use { inputStream ->
+      var bytesRead: Long = 0
+      var currentPartSize: Long = 0
+      val buffer = ByteArray(1024)
+      var length: Int
+      var outputStream: OutputStream
+
+      while (inputStream.read(buffer).also { length = it } > 0) {
+        // If current part size exceeds or equals partSize, move to the next part
+        if (currentPartSize >= partSize || bytesRead == 0L) {
+          outputStream = FileOutputStream(
+            File(storageDir, "testzim.zima${('a' + partNumber - 1).toChar()}")
+          )
+          partNumber++
+          currentPartSize = 0
+        } else {
+          outputStream = FileOutputStream(
+            File(storageDir, "testzim.zima${('a' + partNumber - 2).toChar()}"),
+            true
+          )
+        }
+
+        outputStream.use {
+          it.write(buffer, 0, length)
+        }
+
+        bytesRead += length
+        currentPartSize += length
+      }
+    }
+    val splittedZimFile = File(storageDir, "testzim.zimaa")
+    return if (splittedZimFile.exists()) splittedZimFile else null
+  }
+}