fix(aria-errormessage): adds support for aria-errormessage (#517)

* fix(aria-errormessage): adds support for aria-errormessage

* fix(aria-valid-attr-value): switches from `any` mode to `all`

lib/checks/aria/errormessage.js

@@ -0,0 +1,25 @@
+options = Array.isArray(options) ? options : [];
+
+var attr = node.getAttribute('aria-errormessage'),
+	hasAttr = node.hasAttribute('aria-errormessage');
+
+var doc = axe.commons.dom.getRootNode(node);
+
+function validateAttrValue() {
+	var idref = attr && doc.getElementById(attr);
+	if (idref) {
+		return idref.getAttribute('role') === 'alert' ||
+			idref.getAttribute('aria-live') === 'assertive' ||
+			axe.utils.tokenList(node.getAttribute('aria-describedby') || '').indexOf(attr) > -1;
+	}
+}
+
+// limit results to elements that actually have this attribute
+if (options.indexOf(attr) === -1 && hasAttr) {
+	if (!validateAttrValue()) {
+		this.data(attr);
+		return false;
+	}
+}
+
+return true;

lib/checks/aria/errormessage.json

@@ -0,0 +1,11 @@
+{
+  "id": "aria-errormessage",
+  "evaluate": "errormessage.js",
+  "metadata": {
+    "impact": "critical",
+    "messages": {
+      "pass": "Uses a supported aria-errormessage technique",
+      "fail": "aria-errormessage value{{=it.data && it.data.length > 1 ? 's' : ''}} {{~it.data:value}} `{{=value}}{{~}}` must use a technique to announce the message (e.g., aria-live, aria-describedby, role=alert, etc.)"
+    }
+  }
+}

lib/checks/aria/valid-attr-value.js

@@ -6,13 +6,18 @@ var invalid = [],
 var attr, attrName,
 	attrs = node.attributes;
 
+var skipAttrs = ['aria-errormessage'];
+
 for (var i = 0, l = attrs.length; i < l; i++) {
 	attr = attrs[i];
 	attrName = attr.name;
-	if (options.indexOf(attrName) === -1 && aria.test(attrName) &&
-		!axe.commons.aria.validateAttrValue(node, attrName)) {
+	// skip any attributes handled elsewhere
+	if (!skipAttrs.includes(attrName)) {
+		if (options.indexOf(attrName) === -1 && aria.test(attrName) &&
+			!axe.commons.aria.validateAttrValue(node, attrName)) {
 
-		invalid.push(attrName + '="' + attr.nodeValue + '"');
+			invalid.push(attrName + '="' + attr.nodeValue + '"');
+		}
 	}
 }
 

lib/commons/aria/index.js

@@ -48,6 +48,9 @@ lookupTables.attributes = {
 		type: 'nmtokens',
 		values: ['copy', 'move', 'reference', 'execute', 'popup', 'none']
 	},
+	'aria-errormessage': {
+		type: 'idref'
+	},
 	'aria-expanded': {
 		type: 'nmtoken',
 		values: ['true', 'false', 'undefined']

lib/rules/aria-valid-attr-value.json

@@ -12,9 +12,10 @@
     "description": "Ensures all ARIA attributes have valid values",
     "help": "ARIA attributes must conform to valid values"
   },
-  "all": [],
-  "any": [
-    "aria-valid-attr-value"
+  "all": [
+    "aria-valid-attr-value",
+    "aria-errormessage"
   ],
+  "any": [],
   "none": []
 }

test/checks/aria/errormessage.js

@@ -0,0 +1,49 @@
+describe('aria-errormessage', function () {
+	'use strict';
+
+	var fixture = document.getElementById('fixture');
+
+	var checkContext = axe.testUtils.MockCheckContext();
+
+	afterEach(function () {
+		fixture.innerHTML = '';
+		checkContext._data = null;
+	});
+
+	it('should return false if aria-errormessage value is invalid', function () {
+		var testHTML = '<div></div>';
+		testHTML += '<div id="plain"></div>';
+		fixture.innerHTML = testHTML;
+		var target = fixture.children[0];
+		target.setAttribute('aria-errormessage', 'plain');
+		assert.isFalse(checks['aria-errormessage'].evaluate.call(checkContext, target));
+	});
+
+	it('should return true if aria-errormessage id is alert', function () {
+		var testHTML = '<div></div>';
+		testHTML += '<div id="alert" role="alert"></div>';
+		fixture.innerHTML = testHTML;
+		var target = fixture.children[0];
+		target.setAttribute('aria-errormessage', 'alert');
+		assert.isTrue(checks['aria-errormessage'].evaluate.call(checkContext, target));
+	});
+
+	it('should return true if aria-errormessage id is aria-live=assertive', function () {
+		var testHTML = '<div></div>';
+		testHTML += '<div id="live" aria-live="assertive"></div>';
+		fixture.innerHTML = testHTML;
+		var target = fixture.children[0];
+		target.setAttribute('aria-errormessage', 'live');
+		assert.isTrue(checks['aria-errormessage'].evaluate.call(checkContext, target));
+	});
+
+	it('should return true if aria-errormessage id is aria-describedby', function () {
+		var testHTML = '<div></div>';
+		testHTML += '<div id="plain"></div>';
+		fixture.innerHTML = testHTML;
+		var target = fixture.children[0];
+		target.setAttribute('aria-errormessage', 'plain');
+		target.setAttribute('aria-describedby', 'plain');
+		assert.isTrue(checks['aria-errormessage'].evaluate.call(checkContext, target));
+	});
+});

test/integration/rules/aria-allowed-attr/passes.json

@@ -11,6 +11,6 @@
 		["#pass43"], ["#pass44"], ["#pass45"], ["#pass46"], ["#pass47"], ["#pass48"], ["#pass49"],
 		["#pass50"], ["#pass51"], ["#pass52"], ["#pass53"], ["#pass54"], ["#pass55"], ["#pass56"],
 		["#pass57"], ["#pass58"], ["#pass59"], ["#pass60"], ["#pass61"], ["#pass62"], ["#pass63"],
-		["#pass64"], ["#pass65"], ["#pass66"], ["#pass67"], ["#pass68"]
+    ["#pass64"], ["#pass65"], ["#pass66"], ["#pass67"], ["#pass68"]
 	]
-}
+}

test/integration/rules/aria-valid-attr-value/aria-valid-attr-value.html

@@ -40,6 +40,7 @@ <h2>Violations</h2>
 	<div aria-valuemax="stuff" id="violation32">hi</div>
 	<div aria-valuemin="stuff" id="violation33">hi</div>
 	<div aria-valuenow="stuff" id="violation34">hi</div>
+	<div aria-errormessage="violation35-ref" id="violation35">hi</div><div id="violation35-ref"></div>
 </div>
 <h2>Possible False Positives</h2>
 <div>
@@ -245,6 +246,10 @@ <h2>Possible False Positives</h2>
 	<div aria-valuenow="-.1" id="pass165">hi</div>
 	<div aria-valuenow="-412" id="pass166">hi</div>
 	<div aria-valuetext="stuff" id="pass167">hi</div>
+	<div aria-errormessage="pass168-ref" id="pass168">hi</div><div id="pass168-ref" role="alert"></div>
+	<div aria-errormessage="pass68" id="pass169">hi</div>
+	<div aria-errormessage="ref" aria-describedby="ref" id="pass170">hi</div>
+
 
 	<div id="ref">Hi</div>
 	<div id="ref2">Hi2</div>

test/integration/rules/aria-valid-attr-value/aria-valid-attr-value.json

@@ -7,7 +7,7 @@
 		["#violation12"], ["#violation13"], ["#violation14"], ["#violation15"], ["#violation16"], ["#violation17"],
 		["#violation18"], ["#violation19"], ["#violation20"], ["#violation21"], ["#violation22"], ["#violation23"],
 		["#violation24"], ["#violation25"], ["#violation26"], ["#violation27"], ["#violation28"], ["#violation29"],
-		["#violation30"], ["#violation31"], ["#violation32"], ["#violation33"], ["#violation34"]
+		["#violation30"], ["#violation31"], ["#violation32"], ["#violation33"], ["#violation34"],["#violation35"]
 	],
 	"passes":  [
 		["#pass1"], ["#pass2"], ["#pass3"], ["#pass4"], ["#pass5"], ["#pass6"], ["#pass7"], ["#pass8"], ["#pass9"],
@@ -31,6 +31,7 @@
 		["#pass140"], ["#pass141"], ["#pass142"], ["#pass143"], ["#pass144"], ["#pass145"], ["#pass146"],
 		["#pass147"], ["#pass148"], ["#pass149"], ["#pass150"], ["#pass151"], ["#pass152"], ["#pass153"],
 		["#pass154"], ["#pass155"], ["#pass156"], ["#pass157"], ["#pass158"], ["#pass159"], ["#pass160"],
-		["#pass161"], ["#pass162"], ["#pass163"], ["#pass164"], ["#pass165"], ["#pass166"], ["#pass167"]
+    ["#pass161"], ["#pass162"], ["#pass163"], ["#pass164"], ["#pass165"], ["#pass166"], ["#pass167"],
+    ["#pass168"], ["#pass169"], ["#pass170"]
 	]
 }