diff --git a/tests/testthat/test-guides.R b/tests/testthat/test-guides.R
index ac704fdf79..9531abfa56 100644
--- a/tests/testthat/test-guides.R
+++ b/tests/testthat/test-guides.R
@@ -178,10 +178,15 @@ test_that("guide merging for guide_legend() works as expected", {
     scales <- scales_list()
     scales$add(scale1)
     scales$add(scale2)
+    scales <- scales$scales
+
+    aesthetics <- lapply(scales, `[[`, "aesthetics")
+    scales <- rep.int(scales, lengths(aesthetics))
+    aesthetics <- unlist(aesthetics, FALSE, FALSE)
 
     guides <- guides_list(NULL)
-    guides <- guides$setup(scales$scales)
-    guides$train(scales$scales, "vertical", labs())
+    guides <- guides$setup(scales, aesthetics)
+    guides$train(scales, "vertical", labs())
     guides$merge()
     guides$params
   }
@@ -279,7 +284,7 @@ test_that("legend reverse argument reverses the key", {
   scale$train(LETTERS[1:4])
 
   guides <- guides_list(NULL)
-  guides <- guides$setup(list(scale))
+  guides <- guides$setup(list(scale), "colour")
 
   guides$params[[1]]$reverse <- FALSE
   guides$train(list(scale), "horizontal", labels = labs())