diff --git a/inst/tests/tests.Rraw b/inst/tests/tests.Rraw
index 508bf6aa0..f144532cf 100644
--- a/inst/tests/tests.Rraw
+++ b/inst/tests/tests.Rraw
@@ -21517,6 +21517,6 @@ dt_melt = data.table(a = 1:2, b = 3:4)
 test(2365.1, melt(df_melt, id.vars=1:2), melt(dt_melt, id.vars=1:2))
 
 # test for data.frame reshape for dcast
-df_dcast = data.frame(a = c("x", "y"), b = 1:2, v = 3:4)
+df_dcast = data.frame(a = c("x", "y"), b = 1:2, v = 3:4, stringsAsFactors = FALSE)
 dt_dcast = data.table(a = c("x", "y"), b = 1:2, v = 3:4)
 test(2365.2, dcast(df_dcast, a ~ b, value.var = "v"), dcast(dt_dcast, a ~ b, value.var = "v"))