diff --git a/tests/functional/eval-store.sh b/tests/functional/eval-store.sh
index 202e7b004..92faa4005 100755
--- a/tests/functional/eval-store.sh
+++ b/tests/functional/eval-store.sh
@@ -52,3 +52,7 @@ rm -rf "$eval_store"
 [[ $(nix eval --eval-store "$eval_store?require-sigs=false" --impure --raw --file ./ifd.nix) = hi ]]
 ls $NIX_STORE_DIR/*dependencies-top/foobar
 (! ls $eval_store/nix/store/*dependencies-top/foobar)
+
+# Can't write .drv by default
+(! nix-instantiate dependencies.nix --eval-store "dummy://")
+nix-instantiate dependencies.nix --eval-store "dummy://?read-only=false"
diff --git a/tests/functional/flakes/flakes.sh b/tests/functional/flakes/flakes.sh
index 7b5be112e..97d238654 100755
--- a/tests/functional/flakes/flakes.sh
+++ b/tests/functional/flakes/flakes.sh
@@ -406,6 +406,7 @@ nix flake update flake1 flake2/flake1 --flake "$flake3Dir"
 
 # Test 'nix flake metadata --json'.
 nix flake metadata "$flake3Dir" --json | jq .
+nix flake metadata "$flake3Dir" --json --eval-store "dummy://?read-only=false" | jq .
 
 # Test flake in store does not evaluate.
 rm -rf $badFlakeDir
diff --git a/tests/nixos/github-flakes.nix b/tests/nixos/github-flakes.nix
index 91fd6b062..d14cd9d0c 100644
--- a/tests/nixos/github-flakes.nix
+++ b/tests/nixos/github-flakes.nix
@@ -219,6 +219,7 @@ in
 
       client.succeed("nix registry pin nixpkgs")
       client.succeed("nix flake metadata nixpkgs --tarball-ttl 0 >&2")
+      client.succeed("nix eval nixpkgs#hello --eval-store dummy://?read-only=false >&2")
 
       # Test fetchTree on a github URL.
       hash = client.succeed(f"nix eval --no-trust-tarballs-from-git-forges --raw --expr '(fetchTree {info['url']}).narHash'")