Support directly selecting signalbackup.

app/src/test/java/org/thoughtcrime/securesms/backup/v2/local/ArchiveFileSystemTest.kt

@@ -0,0 +1,109 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.backup.v2.local
+
+import android.app.Application
+import android.content.Context
+import androidx.documentfile.provider.DocumentFile
+import androidx.test.core.app.ApplicationProvider
+import assertk.assertThat
+import assertk.assertions.isFalse
+import assertk.assertions.isNotNull
+import assertk.assertions.isNull
+import assertk.assertions.isTrue
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TemporaryFolder
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+@RunWith(RobolectricTestRunner::class)
+@Config(manifest = Config.NONE, application = Application::class)
+class ArchiveFileSystemTest {
+
+  @get:Rule
+  val temporaryFolder = TemporaryFolder()
+
+  private val context: Context = ApplicationProvider.getApplicationContext()
+
+  @Test
+  fun `openForRestore succeeds when given the parent directory`() {
+    val parent = temporaryFolder.newFolder()
+    buildSignalBackupsStructure(parent)
+
+    val result = ArchiveFileSystem.openForRestore(context, DocumentFile.fromFile(parent))
+
+    assertThat(result).isNotNull()
+  }
+
+  @Test
+  fun `openForRestore isRootedAtSignalBackups is false when given the parent directory`() {
+    val parent = temporaryFolder.newFolder()
+    buildSignalBackupsStructure(parent)
+
+    val result = ArchiveFileSystem.openForRestore(context, DocumentFile.fromFile(parent))!!
+
+    assertThat(result.isRootedAtSignalBackups).isFalse()
+  }
+
+  @Test
+  fun `openForRestore succeeds when given the SignalBackups directory directly`() {
+    val parent = temporaryFolder.newFolder()
+    val signalBackups = buildSignalBackupsStructure(parent)
+
+    val result = ArchiveFileSystem.openForRestore(context, DocumentFile.fromFile(signalBackups))
+
+    assertThat(result).isNotNull()
+  }
+
+  @Test
+  fun `openForRestore isRootedAtSignalBackups is true when given the SignalBackups directory directly`() {
+    val parent = temporaryFolder.newFolder()
+    val signalBackups = buildSignalBackupsStructure(parent)
+
+    val result = ArchiveFileSystem.openForRestore(context, DocumentFile.fromFile(signalBackups))!!
+
+    assertThat(result.isRootedAtSignalBackups).isTrue()
+  }
+
+  @Test
+  fun `openForRestore isRootedAtSignalBackups is false when parent is named SignalBackups but contains a real SignalBackups subfolder`() {
+    val outerSignalBackups = temporaryFolder.newFolder(ArchiveFileSystem.MAIN_DIRECTORY_NAME)
+    buildSignalBackupsStructure(outerSignalBackups)
+
+    val result = ArchiveFileSystem.openForRestore(context, DocumentFile.fromFile(outerSignalBackups))!!
+
+    assertThat(result.isRootedAtSignalBackups).isFalse()
+  }
+
+  @Test
+  fun `openForRestore returns null for a directory named SignalBackups without expected structure`() {
+    val fakeSignalBackups = temporaryFolder.newFolder(ArchiveFileSystem.MAIN_DIRECTORY_NAME)
+
+    val result = ArchiveFileSystem.openForRestore(context, DocumentFile.fromFile(fakeSignalBackups))
+
+    assertThat(result).isNull()
+  }
+
+  @Test
+  fun `openForRestore returns null for an unrelated directory`() {
+    val unrelated = temporaryFolder.newFolder("SomeOtherFolder")
+
+    val result = ArchiveFileSystem.openForRestore(context, DocumentFile.fromFile(unrelated))
+
+    assertThat(result).isNull()
+  }
+
+  /**
+   * Creates the SignalBackups directory structure inside [parent] and returns the SignalBackups directory.
+   */
+  private fun buildSignalBackupsStructure(parent: java.io.File): java.io.File {
+    val signalBackups = parent.resolve(ArchiveFileSystem.MAIN_DIRECTORY_NAME).also { it.mkdir() }
+    signalBackups.resolve("files").mkdir()
+    return signalBackups
+  }
+}