diff --git a/inst/tests/test-rbind.r b/inst/tests/test-rbind.r
index 2d23c6db..3d655cde 100644
--- a/inst/tests/test-rbind.r
+++ b/inst/tests/test-rbind.r
@@ -90,7 +90,7 @@ test_that("time zones are preserved", {
 
   get_tz <- function(x) attr(as.POSIXlt(x), "tz")
 
-  tzs <- c("", "CET", "UTC")
+  tzs <- c("CET", "UTC")
   for(tz in tzs) {
     start <- data.frame(x = as.POSIXct(dstart, tz = tz))
     end <- data.frame(x = as.POSIXct(dstop, tz = tz))