GODT-2170: Use client-side draft update in integration tests

tests/ctx_test.go

@@ -230,36 +230,28 @@ func (t *testCtx) getMBoxID(userID string, name string) string {
 // getDraftID will return the API ID of draft message with draftIndex, where
 // draftIndex is similar to sequential ID i.e. 1 represents the first message
 // of draft folder sorted by API creation time.
-func (t *testCtx) getDraftID(username string, draftIndex int) string {
-	if draftIndex < 1 {
-		panic(fmt.Sprintf("draft index suppose to be non-zero positive integer, but have %d", draftIndex))
-	}
-
+func (t *testCtx) getDraftID(username string, draftIndex int) (string, error) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
 	var draftID string
 
 	if err := t.withClient(ctx, username, func(ctx context.Context, client *proton.Client) error {
-		messages, err := client.GetMessageMetadata(
-			ctx, proton.MessageFilter{LabelID: proton.DraftsLabel},
-		)
+		messages, err := client.GetMessageMetadata(ctx, proton.MessageFilter{LabelID: proton.DraftsLabel})
 		if err != nil {
-			panic(err)
-		}
-
-		if len(messages) < draftIndex {
-			panic("draft index too high")
+			return fmt.Errorf("failed to get message metadata: %w", err)
+		} else if len(messages) < draftIndex {
+			return fmt.Errorf("draft index %d is out of range", draftIndex)
 		}
 
 		draftID = messages[draftIndex-1].ID
 
 		return nil
 	}); err != nil {
-		panic(err)
+		return "", err
 	}
 
-	return draftID
+	return draftID, nil
 }
 
 func (t *testCtx) getLastCall(method, pathExp string) (server.Call, error) {