diff --git a/test/.eslintrc.json b/test/.eslintrc.json
index 99eee4b4..c8e3c4a0 100644
--- a/test/.eslintrc.json
+++ b/test/.eslintrc.json
@@ -6,6 +6,7 @@
     "no-global-assign": 0,
     "no-empty": ["error", { "allowEmptyCatch": true }],
     "no-shadow": "error",
+    "prefer-const": "error",
     "es5/no-block-scoping": 0,
     "es5/no-arrow-functions": 0,
     "es5/no-template-literals": 0,
diff --git a/test/module_test.js b/test/module_test.js
index 0ea97646..1aba4522 100644
--- a/test/module_test.js
+++ b/test/module_test.js
@@ -258,9 +258,9 @@ describe("control flow", () => {
     let didc = false;
     let didx = false;
 
-    let conda = derivable.atom("a");
-    let condb = derivable.atom("b");
-    let condc = derivable.atom("c");
+    const conda = derivable.atom("a");
+    const condb = derivable.atom("b");
+    const condc = derivable.atom("c");
 
     const chooseAPath = switcheroo.switch(
       conda,