R Under development (unstable) (2023-11-02 r85465 ucrt) -- "Unsuffered Consequences"
Copyright (C) 2023 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> if (.Platform$OS.type != "windows") {
+     library(lme4)
+     library(testthat)
+     fm1 <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy)
+     expect_equal(colnames(model.frame(fm1)),c("Reaction","Days","Subject"))
+     expect_equal(colnames(model.frame(fm1,fixed.only=TRUE)),c("Reaction","Days"))
+     expect_equal(formula(fm1),Reaction ~ Days + (Days | Subject))
+     expect_equal(formula(fm1,fixed.only=TRUE),Reaction ~ Days)
+ 
+     ## ugly example: model frame with compound elements
+     fm2 <- lmer(log(Reaction) ~ splines::ns(Days,3) +
+                     + I(1+Days^3) + (Days|Subject), sleepstudy)
+     expect_equal(names(model.frame(fm2)),
+                  c("log(Reaction)", "splines::ns(Days, 3)",
+                    "I(1 + Days^3)", "Days", "Subject"))
+     expect_equal(names(model.frame(fm2,fixed.only=TRUE)),
+                  c("log(Reaction)", "splines::ns(Days, 3)",
+                    "I(1 + Days^3)"))
+ 
+ } ## skip on windows (for speed)
> 
> proc.time()
   user  system elapsed 
   0.18    0.09    0.26