Write simple test for pdf generator

Signed-off-by: Álvaro Brey <alvaro.brey@nextcloud.com>

app/src/androidTest/java/com/nextcloud/client/documentscan/GeneratePDFUseCaseTest.kt

@@ -0,0 +1,86 @@
+/*
+ * Nextcloud Android client application
+ *
+ *  @author Álvaro Brey
+ *  Copyright (C) 2023 Álvaro Brey
+ *  Copyright (C) 2023 Nextcloud GmbH
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or 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 AFFERO GENERAL PUBLIC LICENSE for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public
+ * License along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package com.nextcloud.client.documentscan
+
+import android.graphics.pdf.PdfRenderer
+import android.os.ParcelFileDescriptor
+import com.nextcloud.client.logger.Logger
+import com.owncloud.android.AbstractIT
+import io.mockk.MockKAnnotations
+import io.mockk.impl.annotations.MockK
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+import java.io.File
+
+internal class GeneratePDFUseCaseTest : AbstractIT() {
+
+    @MockK
+    private lateinit var logger: Logger
+
+    private lateinit var sut: GeneratePDFUseCase
+
+    @Before
+    fun setUp() {
+        MockKAnnotations.init(this, relaxed = true)
+        sut = GeneratePDFUseCase(logger)
+    }
+
+    @Test
+    fun invalidArguments_shouldReturnFalse() {
+        var result = sut.execute(emptyList(), "/test/foo.pdf")
+        assertFalse("Usecase does not indicate failure with invalid arguments", result)
+        result = sut.execute(listOf("/test.jpg"), "")
+        assertFalse("Usecase does not indicate failure with invalid arguments", result)
+    }
+
+    @Test
+    fun generatePdf_checkPages() {
+        // can't think of how to test the _content_ of the pages
+        val images = listOf(
+            getFile("image.jpg"),
+            getFile("christine.jpg")
+        ).map { it.path }
+
+        val output = "/sdcard/test.pdf"
+
+        val result = sut.execute(images, output)
+
+        assertTrue("Usecase does not indicate success", result)
+
+        val outputFile = File(output)
+
+        assertTrue("Output file does not exist", outputFile.exists())
+
+        ParcelFileDescriptor.open(outputFile, ParcelFileDescriptor.MODE_READ_ONLY).use {
+            PdfRenderer(it).use { renderer ->
+                val pageCount = renderer.pageCount
+                assertTrue("Page count is not correct", pageCount == 2)
+            }
+        }
+
+        // clean up
+        outputFile.delete()
+    }
+}

app/src/androidTest/java/com/nextcloud/client/documentscan/PDFGeneratorTest.kt

@@ -1,28 +0,0 @@
-/*
- * Nextcloud Android client application
- *
- *  @author Álvaro Brey
- *  Copyright (C) 2023 Álvaro Brey
- *  Copyright (C) 2023 Nextcloud GmbH
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
- * License as published by the Free Software Foundation; either
- * version 3 of the License, or 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 AFFERO GENERAL PUBLIC LICENSE for more details.
- *
- * You should have received a copy of the GNU Affero General Public
- * License along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- */
-
-package com.nextcloud.client.documentscan
-
-internal class PDFGeneratorTest {
-
-    // TODO
-}