diff --git a/tests/functional/flakes/dubious-query.sh b/tests/functional/flakes/dubious-query.sh
new file mode 100644
index 000000000000..0f885bde9d4c
--- /dev/null
+++ b/tests/functional/flakes/dubious-query.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+source ./common.sh
+
+requireGit
+
+nixpkgsDir="$TEST_ROOT/nixpkgs"
+createGitRepo "$nixpkgsDir"
+createSimpleGitFlake "$nixpkgsDir"
+
+# Check that a flakeref without a query is accepted correctly.
+expectStderr 0 nix --offline build --dry-run "git+file://$nixpkgsDir#foo"
+
+# Check that a flakeref with a good query is accepted correctly.
+expectStderr 0 nix --offline build --dry-run "git+file://$nixpkgsDir?foo=bar#foo"
+
+# Check that we get the dubious query warning, when passing in a query without an equal sign.
+expectStderr 0 nix --offline build --dry-run "git+file://$nixpkgsDir?bar#foo" \
+  | grepQuiet "warning: dubious URI query 'bar' is missing equal sign '=', ignoring"
+
+# Check that the anchor (#) is taken as a whole, not split, and throws an error.
+expectStderr 1 nix --offline build --dry-run "git+file://$nixpkgsDir#foo?bar" \
+  | grepQuiet "error: flake 'git+file://$nixpkgsDir' does not provide attribute 'packages.$system.foo?bar', 'legacyPackages.$system.foo?bar' or 'foo?bar'"
diff --git a/tests/functional/flakes/local.mk b/tests/functional/flakes/local.mk
index 71e50ad073fc..a37840240f96 100644
--- a/tests/functional/flakes/local.mk
+++ b/tests/functional/flakes/local.mk
@@ -19,6 +19,7 @@ flake-tests := \
   $(d)/eval-cache.sh \
   $(d)/search-root.sh \
   $(d)/config.sh \
-  $(d)/show.sh
+  $(d)/show.sh \
+  $(d)/dubious-query.sh
 
 install-tests-groups += flake
diff --git a/tests/functional/flakes/meson.build b/tests/functional/flakes/meson.build
index 8c1afd6ff051..4f455fcce7b9 100644
--- a/tests/functional/flakes/meson.build
+++ b/tests/functional/flakes/meson.build
@@ -23,6 +23,7 @@ suites += {
     'search-root.sh',
     'config.sh',
     'show.sh',
+    'dubious-query.sh',
   ],
   'workdir': meson.current_build_dir(),
 }