diff --git a/R/simulate_choices.R b/R/simulate_choices.R
index def513d0d9e40ebc27e1c4d6f0348b8f55f9aeef..5ec9b25bc14219afd361675bee829a466993eea6 100644
--- a/R/simulate_choices.R
+++ b/R/simulate_choices.R
@@ -42,7 +42,7 @@ simulate_choices <- function(data=datadet, utility =utils, setspp) {  #the part
   if(exists("decisiongroups"))  {     ### create a new variable to classify decision groups.
 
     data = dplyr::mutate(data,group = as.numeric(cut(dplyr::row_number(),
-                                              breaks = decisiongroups * n(),
+                                              breaks = decisiongroups * dplyr::n(),
                                               labels = seq_along(decisiongroups[-length(decisiongroups)]),
                                               include.lowest = TRUE)))
 
diff --git a/tests/manual-tests/SE_Drive.R b/tests/manual-tests/SE_Drive.R
new file mode 100644
index 0000000000000000000000000000000000000000..b4d977b687245988ff069d80753e821549c3774b
--- /dev/null
+++ b/tests/manual-tests/SE_Drive.R
@@ -0,0 +1,57 @@
+
+
+rm(list=ls())
+devtools::load_all()
+
+
+library(rlang)
+
+designpath<- system.file("extdata","SE_DRIVE" ,package = "simulateDCE")
+
+resps =120  # number of respondents
+nosim= 2 # number of simulations to run (about 500 is minimum)
+
+
+
+
+
+
+# bpreis = -0.036
+# blade  = -0.034
+# bwarte = -0.049
+
+
+decisiongroups=c(0,0.7,1)
+
+# wrong parameters
+
+#
+bpreis = -0.01
+blade = -0.07
+bwarte = 0.02
+
+manipulations = list(alt1.x2=     expr(alt1.x2/10),
+                     alt1.x3=     expr(alt1.x3/10),
+                     alt2.x2=     expr(alt2.x2/10),
+                     alt2.x3=     expr(alt2.x3/10)
+)
+
+
+#place your utility functions here
+u<-list( u1 =
+
+           list(
+             v1 =V.1~  bpreis * alt1.x1 + blade*alt1.x2 + bwarte*alt1.x3   ,
+             v2 =V.2~  bpreis * alt2.x1 + blade*alt2.x2 + bwarte*alt2.x3
+           )
+
+         ,
+         u2 = list(  v1 =V.1~  bpreis * alt1.x1    ,
+                     v2 =V.2~  bpreis * alt2.x1)
+
+)
+
+
+destype="ngene"
+
+sedrive <- sim_all()