diff --git a/src/index.js b/src/index.js
index de62076..8dd214f 100644
--- a/src/index.js
+++ b/src/index.js
@@ -5,8 +5,12 @@ function b() {
     console.log('a', eval(window.data));
 }
 
+function c() {
+    console.log('a', eval(window.data));
+}
 
 module.exports = {
     a,
-    b
+    b,
+    c
 }
\ No newline at end of file
diff --git a/tests/index.test.js b/tests/index.test.js
index 734089b..430759e 100644
--- a/tests/index.test.js
+++ b/tests/index.test.js
@@ -6,4 +6,19 @@ describe('a', () => {
         expect(a).toBeInstanceOf(Function)
         expect(a()).toBeUndefined()
     })
+    it('test1', () => {
+        // is function
+        expect(a).toBeInstanceOf(Function)
+        expect(a()).toBeUndefined()
+    })
+    it('test2', () => {
+        // is function
+        expect(a).toBeInstanceOf(Function)
+        expect(a()).toBeUndefined()
+    })
+    it('test3', () => {
+        // is function
+        expect(a).toBeInstanceOf(Function)
+        expect(a()).toBeUndefined()
+    })
 })
\ No newline at end of file