Sort files returned by getFiles by time (oldest first).

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxApi.java

@@ -11,6 +11,7 @@ import java.io.IOException;
 import java.util.Collection;
 import java.util.List;
 
+import javax.annotation.Nonnull;
 import javax.annotation.concurrent.Immutable;
 
 interface MailboxApi {
@@ -130,7 +131,7 @@ interface MailboxApi {
 	}
 
 	@JsonSerialize
-	class MailboxFile {
+	class MailboxFile implements Comparable<MailboxFile> {
 		public final MailboxId name;
 		public final long time;
 
@@ -138,6 +139,13 @@ interface MailboxApi {
 			this.name = name;
 			this.time = time;
 		}
+
+		@Override
+		public int compareTo(@Nonnull MailboxApi.MailboxFile mailboxFile) {
+			//noinspection UseCompareMethod
+			return time < mailboxFile.time ? -1 :
+					(time == mailboxFile.time ? 0 : 1);
+		}
 	}
 
 	@Immutable

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxApiImpl.java

@@ -17,6 +17,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 
 import javax.inject.Inject;
@@ -200,6 +201,7 @@ class MailboxApiImpl implements MailboxApi {
 				if (time < 1) throw new ApiException();
 				list.add(new MailboxFile(MailboxId.fromString(name), time));
 			}
+			Collections.sort(list);
 			return list;
 		} catch (JacksonException e) {
 			throw new ApiException();

bramble-core/src/test/java/org/briarproject/bramble/mailbox/MailboxIntegrationTest.java

@@ -194,14 +194,10 @@ public class MailboxIntegrationTest extends BrambleTestCase {
 				file3downloaded);
 		byte[] downloadedBytes2 = readBytes(file2downloaded);
 		byte[] downloadedBytes3 = readBytes(file3downloaded);
-		// file order is not preserved, so we don't know what file is which
-		if (downloadedBytes2.length == bytes2.length) {
-			assertArrayEquals(bytes2, downloadedBytes2);
-			assertArrayEquals(bytes3, downloadedBytes3);
-		} else {
-			assertArrayEquals(bytes2, downloadedBytes3);
-			assertArrayEquals(bytes3, downloadedBytes2);
-		}
+		// file order is preserved (sorted by time),
+		// so we know what file is which
+		assertArrayEquals(bytes2, downloadedBytes2);
+		assertArrayEquals(bytes3, downloadedBytes3);
 
 		// contact can't download files again, even if knowing name
 		File file2forbidden = folder.newFile();