feat: Add shadow DOM to landmark check

lib/checks/navigation/landmark.js

@@ -1 +1 @@
-return node.getElementsByTagName('main').length > 0 || !!node.querySelector('[role="main"]') ;
+return axe.utils.querySelectorAll(virtualNode, 'main, [role="main"]').length > 0;

test/checks/navigation/landmark.js

@@ -2,24 +2,54 @@ describe('landmark', function () {
 	'use strict';
 
 	var fixture = document.getElementById('fixture');
+	var checkSetup = axe.testUtils.checkSetup;
+	var shadowSupport = axe.testUtils.shadowSupport;
 
 	afterEach(function () {
 		fixture.innerHTML = '';
 	});
 
 	it('should return true when role=main is found', function () {
-		fixture.innerHTML = '<div role="main"></div>';
-		assert.isTrue(checks.landmark.evaluate(fixture));
+		var checkArgs = checkSetup('<div role="main"></div>', '#fixture');
+		assert.isTrue(checks.landmark.evaluate.apply(null, checkArgs));
 	});
 
 	it('should return true when <main> is found', function () {
-		fixture.innerHTML = '<main></main>';
-		assert.isTrue(checks.landmark.evaluate(fixture));
+		var checkArgs = checkSetup('<main></main>', '#fixture');
+		assert.isTrue(checks.landmark.evaluate.apply(null, checkArgs));
 	});
 
 	it('should otherwise return false', function () {
-		fixture.innerHTML = '<div role="contentinfo"></div>';
-		assert.isFalse(checks.landmark.evaluate(fixture));
+		var checkArgs = checkSetup('<div role="contentinfo"></div>', '#fixture');
+		assert.isFalse(checks.landmark.evaluate.apply(null, checkArgs));
+	});
+
+	(shadowSupport ? it : xit)('should not automatically pass if there is a shadow tree', function () {
+		var node = document.createElement('div');
+		var shadow = node.attachShadow({ mode: 'open' });
+		shadow.innerHTML = '<div></div>';
+		var checkArgs = checkSetup(node, '#fixture');
+
+		assert.isFalse(checks.landmark.evaluate.apply(null, checkArgs));
+	});
+
+	(shadowSupport ? it : xit)('should find elements inside shadow trees', function () {
+		var node = document.createElement('div');
+		var shadow = node.attachShadow({ mode: 'open' });
+		shadow.innerHTML = '<main></main>';
+		var checkArgs = checkSetup(node, '#fixture');
+
+		assert.isTrue(checks.landmark.evaluate.apply(null, checkArgs));
+	});
+
+	(shadowSupport ? it : xit)('should find elements slotted in shadow trees', function () {
+		var node = document.createElement('div');
+		node.innerHTML = '<main></main>';
+		var shadow = node.attachShadow({ mode: 'open' });
+		shadow.innerHTML = '<slot></slot>';
+		var checkArgs = checkSetup(node, '#fixture');
+
+		assert.isTrue(checks.landmark.evaluate.apply(null, checkArgs));
 	});
 
 });