Test that cjs tests still work when using es-modules.

Adds an integration test that uses cjs modules but is called with
the --es-modules flag.

test/integration/es-modules.spec.js

@@ -35,4 +35,21 @@ describe('esModules', function () {
       });
     });
   });
+
+  describe('loading of cjs tests when running with --experimental-modules and --dynamic-import', function () {
+    it('should load cjs test', function (done) {
+      this.timeout(1000);
+      run('es-modules/cjs-test.fixture.js', ['--es-modules', '--experimental-modules', '--harmony-dynamic-import'], function (err, res) {
+        if (err) {
+          done(err);
+          return;
+        }
+        assert.equal(res.pending, 0);
+        assert.equal(res.passing, 1);
+        assert.equal(res.failing, 0);
+        assert.equal(res.code, 0);
+        done();
+      });
+    });
+  });
 });

test/integration/fixtures/es-modules/cjs-module.js

@@ -0,0 +1,3 @@
+'use strict';
+
+exports.cjs = 'cjs';

test/integration/fixtures/es-modules/cjs-test.fixture.js

@@ -0,0 +1,8 @@
+var cjs = require('./cjs-module').cjs;
+
+
+describe('testing common js require', function () {
+  it('should be able to require cjs modules', function () {
+    assert(cjs, 'cjs');
+  });
+});