Added unit test cases for testing this functionality with all possibl…

…e scenarios e.g. "Download Failed", "Download Successfull", "When no reader application is installed in device", "File opens in external reader application", "When user clicks on NO Thanks button".

app/src/androidTest/java/org/kiwix/kiwixmobile/utils/DownloadOrOpenEpubAndPdfHandlerTest.kt

@@ -0,0 +1,201 @@
+/*
+ * 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.utils
+
+import android.app.Activity
+import android.webkit.WebResourceResponse
+import android.widget.Toast
+import io.mockk.every
+import io.mockk.justRun
+import io.mockk.mockk
+import io.mockk.mockkStatic
+import io.mockk.slot
+import io.mockk.verify
+import org.junit.Before
+import org.junit.Test
+import org.kiwix.kiwixmobile.core.R
+import org.kiwix.kiwixmobile.core.extensions.toast
+import org.kiwix.kiwixmobile.core.reader.ZimReaderContainer
+import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
+import org.kiwix.kiwixmobile.core.utils.dialog.AlertDialogShower
+import org.kiwix.kiwixmobile.core.utils.dialog.DownloadOrOpenEpubAndPdfHandler
+import org.kiwix.kiwixmobile.core.utils.dialog.KiwixDialog
+import java.io.File
+import java.io.InputStream
+
+class DownloadOrOpenEpubAndPdfHandlerTest {
+  private val demoUrl = "content://demoPdf.pdf"
+  private val demoFileName = "demoPdf.pdf"
+  private val sharedPreferenceUtil: SharedPreferenceUtil = mockk()
+  private val zimReaderContainer: ZimReaderContainer = mockk()
+  private val alertDialogShower: AlertDialogShower = mockk(relaxed = true)
+  private val savedFile: File = mockk(relaxed = true)
+  private val activity: Activity = mockk()
+  private val webResourceResponse: WebResourceResponse = mockk()
+  private val inputStream: InputStream = mockk()
+  private val downloadOrOpenEpubAndPdfHandler = DownloadOrOpenEpubAndPdfHandler(
+    activity,
+    sharedPreferenceUtil,
+    alertDialogShower,
+    zimReaderContainer
+  )
+
+  @Before
+  fun before() {
+    every { savedFile.name } returns demoFileName
+    every { sharedPreferenceUtil.isPlayStoreBuildWithAndroid11OrAbove() } returns true
+    every { inputStream.read(array()) } returns 1024
+    every { webResourceResponse.data } returns inputStream
+    every {
+      zimReaderContainer.load(
+        demoUrl,
+        emptyMap()
+      )
+    } returns webResourceResponse
+    every { activity.packageManager } returns mockk()
+    every { activity.packageName } returns "org.kiwix.kiwixmobile"
+    every {
+      activity.getString(
+        R.string.save_media_saved,
+        demoFileName
+      )
+    } returns "Saved media as $demoFileName to Downloads/org.kiwix…/"
+    every { savedFile.path } returns "Emulated/0/Downloads/$demoFileName"
+    every { savedFile.exists() } returns true
+    downloadOrOpenEpubAndPdfHandler.intent = mockk()
+    every { downloadOrOpenEpubAndPdfHandler.intent.setDataAndType(any(), any()) } returns mockk()
+    every { downloadOrOpenEpubAndPdfHandler.intent.setFlags(any()) } returns mockk()
+    every { downloadOrOpenEpubAndPdfHandler.intent.addFlags(any()) } returns mockk()
+  }
+
+  @Test
+  fun testOpeningFileInExternalReaderApplication() {
+    every {
+      downloadOrOpenEpubAndPdfHandler.intent.resolveActivity(activity.packageManager)
+    } returns mockk()
+    every { activity.startActivity(downloadOrOpenEpubAndPdfHandler.intent) } returns mockk()
+    val lambdaSlot = slot<() -> Unit>()
+    downloadOrOpenEpubAndPdfHandler.showDownloadOrOpenEpubAndPdfDialog(demoUrl, "application/pdf")
+    verify {
+      alertDialogShower.show(
+        KiwixDialog.DownloadOrOpenEpubAndPdf,
+        capture(lambdaSlot),
+        any(),
+        any()
+      )
+    }
+    lambdaSlot.captured.invoke()
+    verify {
+      activity.startActivity(downloadOrOpenEpubAndPdfHandler.intent)
+    }
+  }
+
+  @Test
+  fun testOpeningFileWhenNoReaderApplicationInstalled() {
+    every {
+      downloadOrOpenEpubAndPdfHandler.intent.resolveActivity(activity.packageManager)
+    } returns null
+    mockkStatic(Toast::class)
+    justRun {
+      Toast.makeText(activity, R.string.no_reader_application_installed, Toast.LENGTH_LONG).show()
+    }
+    val lambdaSlot = slot<() -> Unit>()
+    downloadOrOpenEpubAndPdfHandler.showDownloadOrOpenEpubAndPdfDialog(demoUrl, "application/pdf")
+    verify {
+      alertDialogShower.show(
+        KiwixDialog.DownloadOrOpenEpubAndPdf,
+        capture(lambdaSlot),
+        any(),
+        any()
+      )
+    }
+    lambdaSlot.captured.invoke()
+    verify { activity.toast(R.string.no_reader_application_installed) }
+  }
+
+  @Test
+  fun testFileDownloadingSuccessfull() {
+    val toastMessage = activity.getString(R.string.save_media_saved, savedFile.name)
+    mockkStatic(Toast::class)
+    justRun {
+      Toast.makeText(
+        activity,
+        toastMessage,
+        Toast.LENGTH_LONG
+      ).show()
+    }
+    val lambdaSlot = slot<() -> Unit>()
+    downloadOrOpenEpubAndPdfHandler.showDownloadOrOpenEpubAndPdfDialog(
+      demoUrl,
+      "application/pdf"
+    )
+    verify {
+      alertDialogShower.show(
+        KiwixDialog.DownloadOrOpenEpubAndPdf,
+        any(),
+        capture(lambdaSlot),
+        any()
+      )
+    }
+    lambdaSlot.captured.invoke()
+    verify { activity.toast(toastMessage) }
+  }
+
+  @Test
+  fun testUserClicksOnNoThanksButton() {
+    val lambdaSlot = slot<() -> Unit>()
+    downloadOrOpenEpubAndPdfHandler.showDownloadOrOpenEpubAndPdfDialog(demoUrl, "application/pdf")
+    verify {
+      alertDialogShower.show(
+        KiwixDialog.DownloadOrOpenEpubAndPdf,
+        any(),
+        any(),
+        capture(lambdaSlot)
+      )
+    }
+    lambdaSlot.captured.invoke()
+    verify(exactly = 0) { activity.startActivity(any()) }
+  }
+
+  @Test
+  fun testIfDownloadFailed() {
+    val downloadOrOpenEpubAndPdfHandler = DownloadOrOpenEpubAndPdfHandler(
+      activity,
+      sharedPreferenceUtil,
+      alertDialogShower,
+      zimReaderContainer
+    )
+    mockkStatic(Toast::class)
+    justRun {
+      Toast.makeText(activity, R.string.save_media_error, Toast.LENGTH_LONG).show()
+    }
+    val lambdaSlot = slot<() -> Unit>()
+    downloadOrOpenEpubAndPdfHandler.showDownloadOrOpenEpubAndPdfDialog(null, "application/pdf")
+    verify {
+      alertDialogShower.show(
+        KiwixDialog.DownloadOrOpenEpubAndPdf,
+        any(),
+        capture(lambdaSlot),
+        any()
+      )
+    }
+    lambdaSlot.captured.invoke()
+    verify { activity.toast(R.string.save_media_error) }
+  }
+}

core/src/main/java/org/kiwix/kiwixmobile/core/utils/dialog/DownloadOrOpenEpubAndPdfHandler.kt

@@ -36,8 +36,9 @@ class DownloadOrOpenEpubAndPdfHandler @Inject constructor(
   private val alertDialogShower: AlertDialogShower,
   private val zimReaderContainer: ZimReaderContainer
 ) {
+  var intent: Intent = Intent(Intent.ACTION_VIEW)
 
-  fun showDownloadOrOpenEpubAndPdfDialog(url: String, documentType: String?) {
+  fun showDownloadOrOpenEpubAndPdfDialog(url: String?, documentType: String?) {
     alertDialogShower.show(
       KiwixDialog.DownloadOrOpenEpubAndPdf,
       { openOrDownloadFile(url, documentType, true) },
@@ -46,7 +47,7 @@ class DownloadOrOpenEpubAndPdfHandler @Inject constructor(
     )
   }
 
-  private fun openOrDownloadFile(url: String, documentType: String?, openFile: Boolean) {
+  private fun openOrDownloadFile(url: String?, documentType: String?, openFile: Boolean) {
     downloadFileFromUrl(
       url,
       null,
@@ -72,7 +73,7 @@ class DownloadOrOpenEpubAndPdfHandler @Inject constructor(
         "${activity.packageName}.fileprovider",
         savedFile
       )
-      val intent = Intent(Intent.ACTION_VIEW).apply {
+      intent.apply {
         setDataAndType(uri, documentType)
         flags = Intent.FLAG_ACTIVITY_NO_HISTORY
         addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)