diff --git a/test/Project.toml b/test/Project.toml
index 34df851..0770c5c 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -12,6 +12,7 @@ Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 [compat]
 Distributions = "0.25"
 Documenter = "0.26.3, 0.27"
+InvertedIndices = "1"
 OffsetArrays = "1"
 Setfield = "0.7.1, 0.8, 1"
 julia = "1"