diff --git a/test/test_tree_2d_eulermulti.jl b/test/test_tree_2d_eulermulti.jl
index 0996da0f676..053cb9bce64 100644
--- a/test/test_tree_2d_eulermulti.jl
+++ b/test/test_tree_2d_eulermulti.jl
@@ -19,6 +19,7 @@ EXAMPLES_DIR = pkgdir(Trixi, "examples", "tree_2d_dgsem")
     u = [-1.7433292819144075, 0.8844413258376495, 0.6050737175812364, 0.8261998359817043, 1.0801186290896465, 0.505654488367698, 0.6364415555805734, 0.851669392285058, 0.31219606420306223, 1.0930477805612038]
     w = cons2entropy(u, equations)
     @test w ≈ ForwardDiff.gradient(u -> Trixi.total_entropy(u, equations), u)
+    # test that `entropy2cons` is the inverse of `cons2entropy`
     @test entropy2cons(w, equations) ≈ u  
 end