validate method supports multiple validators in validatable

bower.json

@@ -21,7 +21,7 @@
   "ignore": [],
   "dependencies": {
     "iron-a11y-announcer": "PolymerElements/iron-a11y-announcer#^1.0.0",
-    "iron-validatable-behavior": "PolymerElements/iron-validatable-behavior#^1.0.0",
+    "iron-validatable-behavior": "https://github.com/tlouisse/iron-validatable-behavior.git#feature/multipleValidators",
     "polymer": "Polymer/polymer#^1.0.0"
   },
   "devDependencies": {
@@ -31,5 +31,9 @@
     "test-fixture": "PolymerElements/test-fixture#^1.0.0",
     "web-component-tester": "^4.0.0",
     "webcomponentsjs": "webcomponents/webcomponentsjs#^0.7.0"
+  },
+  "resolutions": {
+    "iron-validatable-behavior": "feature/multipleValidators",
+    "iron-validator-behavior": "feature/multipleValidators"
   }
 }

iron-input.html

@@ -278,20 +278,11 @@
      * @return {boolean} True if the value is valid.
      */
     validate: function() {
-      // First, check what the browser thinks. Some inputs (like type=number)
-      // behave weirdly and will set the value to "" if something invalid is
-      // entered, but will set the validity correctly.
-      var valid =  this.checkValidity();
-
-      // Only do extra checking if the browser thought this was valid.
-      if (valid) {
-        // Empty, required input is invalid
-        if (this.required && this.value === '') {
-          valid = false;
-        } else if (this.hasValidator()) {
-          valid = Polymer.IronValidatableBehavior.validate.call(this, this.value);
-        }
-      }
+      // Validatable is called first, so it will keep track of all individual states of validators that can be applied to it.
+      var validatableOutcome = Polymer.IronValidatableBehavior.validate.call(this, this.value);
+
+      var requiredValid = this.required ? this.value !== '' : true;
+      var valid = validatableOutcome && this.checkValidity() && requiredValid;
 
       this.invalid = !valid;
       this.fire('iron-input-validate');

test/iron-input.html

@@ -248,6 +248,18 @@
         input.validate();
         assert.isTrue(input.invalid, 'input is invalid');
       });
+
+      test('custom validators will be called when browser validation results in invalid state'/* this enables error reporting per validator */, function() {
+        var node = fixture('native-and-custom-validator');
+        var validator = node[0];
+        var input = node[1];
+        sinon.spy(validator, 'validate');
+        // The validator allows this, but the browser doesn't.
+        input.value = 'zzz';
+        input.validate();
+        assert(validator.validate.called);
+      });
+
     });
 
     suite('a11y', function() {