diff --git a/Project.toml b/Project.toml
index ae8d2da..a82fe25 100644
--- a/Project.toml
+++ b/Project.toml
@@ -9,7 +9,7 @@ RecursiveArrayTools = "731186ca-8d62-57ce-b412-fbd966d074cd"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 
 [compat]
-IntervalArithmetic = "0.20"
+IntervalArithmetic = "0.20 - 0.21"
 MultivariatePolynomials = "0.4 - 0.5"
 RecursiveArrayTools = "2"
 Reexport = "1.2"
diff --git a/test/runtests.jl b/test/runtests.jl
index dae2626..2033751 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -21,8 +21,8 @@ end
 
 @testset "Univariate monomial, rational" begin
     # exported function
-    @test univariate(x^3, 3, Interval(1 // 1, 2 // 1)) == [1 // 1, 2 // 1, 4 // 1, 8 // 1]
-    @test univariate(x, 5, Interval(0 // 1, 1 // 1)) ==
+    @test univariate(x^3, 3, interval(1 // 1, 2 // 1)) == [1 // 1, 2 // 1, 4 // 1, 8 // 1]
+    @test univariate(x, 5, interval(0 // 1, 1 // 1)) ==
           [0 // 1, 1 // 5, 2 // 5, 3 // 5, 4 // 5, 1 // 1]
 
     # internals