diff --git a/test/.eslintrc.json b/test/.eslintrc.json
index 47e71e3e..34849ebf 100644
--- a/test/.eslintrc.json
+++ b/test/.eslintrc.json
@@ -1,4 +1,7 @@
 {
+  "parserOptions": {
+    "ecmaVersion": 8
+  },
   "rules": {
     "no-unused-vars": 0
   },
@@ -34,6 +37,7 @@
     "_fixture": false,
     "gemini": false,
     "flush": false,
-    "ShadyDOM": false
+    "ShadyDOM": false,
+    "nextRender": false
   }
 }
diff --git a/test/helpers.html b/test/helpers.html
new file mode 100644
index 00000000..a65a4e8a
--- /dev/null
+++ b/test/helpers.html
@@ -0,0 +1,14 @@
+<!doctype html>
+
+<head>
+  <link rel="import" href="../../polymer/polymer.html">
+</head>
+<body>
+<script>
+  window.nextRender = (element) => {
+    return new Promise(resolve => {
+      Polymer.RenderStatus.afterNextRender(element, resolve);
+    });
+  };
+</script>
+</body>
\ No newline at end of file
diff --git a/test/test-suites.js b/test/test-suites.js
index ec165a9e..b7ad4f7d 100644
--- a/test/test-suites.js
+++ b/test/test-suites.js
@@ -17,7 +17,8 @@ window.VaadinComboBoxSuites = [
   'item-renderer.html',
   'item-template.html',
   'vaadin-combo-box-dropdown.html',
-  'lazy-loading.html'
+  'lazy-loading.html',
+  'validation.html'
 ];
 
 if (isPolymer2) {
diff --git a/test/validation.html b/test/validation.html
new file mode 100644
index 00000000..e5e79ff1
--- /dev/null
+++ b/test/validation.html
@@ -0,0 +1,55 @@
+<!doctype html>
+<html>
+
+<head>
+  <meta charset="UTF-8">
+  <title>vaadin-combo-box validation tests</title>
+
+  <script src="../../web-component-tester/browser.js"></script>
+  <script src='../../webcomponentsjs/webcomponents-lite.js'></script>
+  <link rel="import" href="../src/vaadin-combo-box.html">
+  <link rel="import" href="helpers.html">
+</head>
+
+<body>
+  <script>
+  describe('initial validation', () => {
+    let comboBox;
+    let validateSpy;
+
+    beforeEach(() => {
+      comboBox = document.createElement('vaadin-combo-box');
+      comboBox.allowCustomValue = true;
+      validateSpy = sinon.spy(comboBox, 'validate');
+    });
+
+    afterEach(() => {
+      comboBox.remove();
+    });
+
+    it('should not validate by default', async() => {
+      document.body.appendChild(comboBox);
+      await nextRender();
+      expect(validateSpy.called).to.be.false;
+    });
+
+    it('should not validate when the field has an initial value', async() => {
+      comboBox.value = 'foo';
+      document.body.appendChild(comboBox);
+      await nextRender();
+      expect(validateSpy.called).to.be.false;
+    });
+
+    it('should not validate when the field has an initial value and invalid', async() => {
+      comboBox.value = 'foo';
+      comboBox.invalid = true;
+      document.body.appendChild(comboBox);
+      await nextRender();
+      expect(validateSpy.called).to.be.false;
+    });
+  });
+  </script>
+
+</body>
+
+</html>
