diff --git a/tests/__helpers.ts b/tests/__helpers.ts
index ce8197008..5db399fd7 100644
--- a/tests/__helpers.ts
+++ b/tests/__helpers.ts
@@ -43,7 +43,7 @@ export function setupTestServer() {
 
   afterEach(() => {
     // https://stackoverflow.com/questions/10378690/remove-route-mappings-in-nodejs-express/28369539#28369539
-    ctx.server._router.stack.forEach((item, i) => {
+    ctx.server._router.stack.forEach((item: any, i: number) => {
       if (item.name === 'mock') ctx.server._router.stack.splice(i, 1)
     })
   })
diff --git a/tests/tsconfig.json b/tests/tsconfig.json
new file mode 100644
index 000000000..859eb7735
--- /dev/null
+++ b/tests/tsconfig.json
@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "target": "esnext",
+    "moduleResolution": "node",
+    "esModuleInterop": true,
+    "rootDir": "..",
+    "strict": true,
+    "noEmit": true
+  },
+  "include": [".."]
+}