diff --git a/test/runtests.jl b/test/runtests.jl
index c44ec71..406a7c0 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -169,6 +169,14 @@ end
                         "JULIA_DEPOT_PATH" => DEPOT_PATH[1],
                     ),
                 )
+
+                # The `each_version` might not be the `julia_version`.
+                manifest_toml_file = joinpath(project, "Manifest.toml")
+                @test isfile(manifest_toml_file)
+                manifest_toml = TOML.parsefile(manifest_toml_file)
+                resolved_version = manifest_toml["julia_version"]
+                run(`juliaup add $resolved_version`)
+
                 output = readchomp(
                     addenv(
                         `julia +$each_version --startup-file=no --project=$project -e "import TestPackage; TestPackage.greet()"`,