diff --git a/test/controller.js b/test/controller.js
index a96e2bd..62b3e43 100644
--- a/test/controller.js
+++ b/test/controller.js
@@ -22,8 +22,8 @@
 
 
 import { Controller } from '../src/estraverse.js';
-import Dumper from './dumper';
-import checkDump from './checkDump';
+import Dumper from './dumper.js';
+import checkDump from './checkDump.js';
 
 describe('controller', function() {
     it('traverse', function() {
diff --git a/test/es6.js b/test/es6.js
index 47e0fac..e3ce920 100644
--- a/test/es6.js
+++ b/test/es6.js
@@ -22,8 +22,8 @@
 //  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
-import Dumper from './dumper';
-import checkDump from './checkDump';
+import Dumper from './dumper.js';
+import checkDump from './checkDump.js';
 import { parse as esprima } from 'esprima';
 import { parse as espree } from 'espree';
 
diff --git a/test/traverse.js b/test/traverse.js
index ae1323c..827a3db 100644
--- a/test/traverse.js
+++ b/test/traverse.js
@@ -21,8 +21,8 @@
 // THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
-import Dumper from './dumper';
-import checkDump from './checkDump';
+import Dumper from './dumper.js';
+import checkDump from './checkDump.js';
 import { traverse } from '../src/estraverse.js';
 
 describe('object expression', function() {