From 949f4f8dfccd018b88f929bd650dc8920ce4f6f0 Mon Sep 17 00:00:00 2001
From: Wilco Fiers <WilcoFiers@users.noreply.github.com>
Date: Mon, 15 May 2023 13:22:43 +0200
Subject: [PATCH] fix(link-in-text-block): set links with pseudo-content for
 review (#4005)

* fix(link-in-text-block): set links with pseudo-content for review

* :robot: Automated formatting fixes

* fix typo
---
 .../link-in-text-block-style-evaluate.js      | 31 ++++++--
 .../color/link-in-text-block-style.json       |  4 +
 locales/_template.json                        |  4 +
 test/checks/color/link-in-text-block-style.js | 77 +++++++++++++------
 .../link-in-text-block.html                   | 18 +++++
 .../link-in-text-block.json                   |  5 +-
 6 files changed, 106 insertions(+), 33 deletions(-)

diff --git a/lib/checks/color/link-in-text-block-style-evaluate.js b/lib/checks/color/link-in-text-block-style-evaluate.js
index aaf6fec010..e07929ea41 100644
--- a/lib/checks/color/link-in-text-block-style-evaluate.js
+++ b/lib/checks/color/link-in-text-block-style-evaluate.js
@@ -9,12 +9,8 @@ const blockLike = [
   'grid',
   'inline-block'
 ];
-function isBlock(elm) {
-  var display = window.getComputedStyle(elm).getPropertyValue('display');
-  return blockLike.indexOf(display) !== -1 || display.substr(0, 6) === 'table-';
-}
 
-function linkInTextBlockStyleEvaluate(node) {
+export default function linkInTextBlockStyleEvaluate(node) {
   if (isBlock(node)) {
     return false;
   }
@@ -30,7 +26,28 @@ function linkInTextBlockStyleEvaluate(node) {
 
   this.relatedNodes([parentBlock]);
 
-  return elementIsDistinct(node, parentBlock);
+  if (elementIsDistinct(node, parentBlock)) {
+    return true;
+  }
+  if (hasPseudoContent(node)) {
+    this.data({ messageKey: 'pseudoContent' });
+    return undefined;
+  }
+  return false;
+}
+
+function isBlock(elm) {
+  var display = window.getComputedStyle(elm).getPropertyValue('display');
+  return blockLike.indexOf(display) !== -1 || display.substr(0, 6) === 'table-';
 }
 
-export default linkInTextBlockStyleEvaluate;
+function hasPseudoContent(node) {
+  for (const pseudo of ['before', 'after']) {
+    const style = window.getComputedStyle(node, `:${pseudo}`);
+    const content = style.getPropertyValue('content');
+    if (content !== 'none') {
+      return true;
+    }
+  }
+  return false;
+}
diff --git a/lib/checks/color/link-in-text-block-style.json b/lib/checks/color/link-in-text-block-style.json
index 566f1cd715..bb909baf12 100644
--- a/lib/checks/color/link-in-text-block-style.json
+++ b/lib/checks/color/link-in-text-block-style.json
@@ -5,6 +5,10 @@
     "impact": "serious",
     "messages": {
       "pass": "Links can be distinguished from surrounding text by visual styling",
+      "incomplete": {
+        "default": "Check if the link needs styling to distinguish it from nearby text",
+        "pseudoContent": "Check if the link's pseudo style is sufficient to distinguish it from the surrounding text"
+      },
       "fail": "The link has no styling (such as underline) to distinguish it from the surrounding text"
     }
   }
diff --git a/locales/_template.json b/locales/_template.json
index 20d4246ba6..3cb970b002 100644
--- a/locales/_template.json
+++ b/locales/_template.json
@@ -623,6 +623,10 @@
     },
     "link-in-text-block-style": {
       "pass": "Links can be distinguished from surrounding text by visual styling",
+      "incomplete": {
+        "default": "Check if the link needs styling to distinguish it from nearby text",
+        "pseudoContent": "Check if the link's pseudo style is sufficient to distinguish it from the surrounding text"
+      },
       "fail": "The link has no styling (such as underline) to distinguish it from the surrounding text"
     },
     "link-in-text-block": {
diff --git a/test/checks/color/link-in-text-block-style.js b/test/checks/color/link-in-text-block-style.js
index 2f79c958e5..2fdb94fc4a 100644
--- a/test/checks/color/link-in-text-block-style.js
+++ b/test/checks/color/link-in-text-block-style.js
@@ -7,6 +7,11 @@ describe('link-in-text-block-style', function () {
 
   var checkContext = axe.testUtils.MockCheckContext();
 
+  const { queryFixture } = axe.testUtils;
+  const linkInBlockStyleCheck = axe.testUtils.getCheckEvaluate(
+    'link-in-text-block-style'
+  );
+
   before(function () {
     styleElm = document.createElement('style');
     document.head.appendChild(styleElm);
@@ -107,11 +112,7 @@ describe('link-in-text-block-style', function () {
       axe.testUtils.flatTreeSetup(fixture);
       var linkElm = document.getElementById('link');
 
-      assert.isFalse(
-        axe.testUtils
-          .getCheckEvaluate('link-in-text-block-style')
-          .call(checkContext, linkElm)
-      );
+      assert.isFalse(linkInBlockStyleCheck.call(checkContext, linkElm));
     });
 
     (shadowSupport.v1 ? it : xit)(
@@ -126,11 +127,7 @@ describe('link-in-text-block-style', function () {
 
         axe.testUtils.flatTreeSetup(fixture);
 
-        assert.isTrue(
-          axe.testUtils
-            .getCheckEvaluate('link-in-text-block-style')
-            .call(checkContext, linkElm)
-        );
+        assert.isTrue(linkInBlockStyleCheck.call(checkContext, linkElm));
       }
     );
 
@@ -148,11 +145,7 @@ describe('link-in-text-block-style', function () {
         axe.testUtils.flatTreeSetup(fixture);
         var linkElm = div.querySelector('a');
 
-        assert.isTrue(
-          axe.testUtils
-            .getCheckEvaluate('link-in-text-block-style')
-            .call(checkContext, linkElm)
-        );
+        assert.isTrue(linkInBlockStyleCheck.call(checkContext, linkElm));
       }
     );
   });
@@ -160,24 +153,58 @@ describe('link-in-text-block-style', function () {
   describe('links distinguished through style', function () {
     it('returns false if link style matches parent', function () {
       var linkElm = getLinkElm({});
-      assert.isFalse(
-        axe.testUtils
-          .getCheckEvaluate('link-in-text-block-style')
-          .call(checkContext, linkElm)
-      );
+      assert.isFalse(linkInBlockStyleCheck.call(checkContext, linkElm));
       assert.equal(checkContext._relatedNodes[0], linkElm.parentNode);
+      assert.isNull(checkContext._data);
     });
 
     it('returns true if link has underline', function () {
       var linkElm = getLinkElm({
         textDecoration: 'underline'
       });
-      assert.isTrue(
-        axe.testUtils
-          .getCheckEvaluate('link-in-text-block-style')
-          .call(checkContext, linkElm)
-      );
+      assert.isTrue(linkInBlockStyleCheck.call(checkContext, linkElm));
       assert.equal(checkContext._relatedNodes[0], linkElm.parentNode);
+      assert.isNull(checkContext._data);
+    });
+
+    it('returns undefined when the link has a :before pseudo element', function () {
+      const link = queryFixture(`
+        <style>
+          a:before { content: '🔗'; }
+          a { text-decoration: none; }
+        </style>
+        <p>A <a href="#" id="target">link</a> inside a block of text</p>
+      `).actualNode;
+      const result = linkInBlockStyleCheck.call(checkContext, link);
+      assert.isUndefined(result);
+      assert.deepEqual(checkContext._data, { messageKey: 'pseudoContent' });
+      assert.equal(checkContext._relatedNodes[0], link.parentNode);
+    });
+
+    it('returns undefined when the link has a :after pseudo element', function () {
+      const link = queryFixture(`
+        <style>
+          a:after { content: ""; }
+          a { text-decoration: none; }
+        </style>
+        <p>A <a href="#" id="target">link</a> inside a block of text</p>
+      `).actualNode;
+      const result = linkInBlockStyleCheck.call(checkContext, link);
+      assert.isUndefined(result);
+      assert.deepEqual(checkContext._data, { messageKey: 'pseudoContent' });
+      assert.equal(checkContext._relatedNodes[0], link.parentNode);
+    });
+
+    it('does not return undefined when the pseudo element content is none', function () {
+      const link = queryFixture(`
+        <style>
+          a:after { content: none; position: absolute; }
+          a { text-decoration: none; }
+        </style>
+        <p>A <a href="#" id="target">link</a> inside a block of text</p>
+      `).actualNode;
+      const result = linkInBlockStyleCheck.call(checkContext, link);
+      assert.isFalse(result);
     });
   });
 });
diff --git a/test/integration/rules/link-in-text-block/link-in-text-block.html b/test/integration/rules/link-in-text-block/link-in-text-block.html
index 260a259e4f..9d69d819d0 100644
--- a/test/integration/rules/link-in-text-block/link-in-text-block.html
+++ b/test/integration/rules/link-in-text-block/link-in-text-block.html
@@ -149,3 +149,21 @@ <h1>Incomplete tests</h1>
     Link test</a
   >
 </p>
+
+<style>
+  #incomplete-pseudo-before {
+    text-decoration: none;
+    position: relative;
+  }
+  #incomplete-pseudo-before:before {
+    content: '';
+    position: absolute;
+    width: 100%;
+    height: 1px;
+    background: purple;
+    bottom: 2px;
+  }
+</style>
+<p id="pseudo">
+  Lorem <a href="#" id="incomplete-pseudo-before">ipsum</a> dolor sit.
+</p>
diff --git a/test/integration/rules/link-in-text-block/link-in-text-block.json b/test/integration/rules/link-in-text-block/link-in-text-block.json
index 366b5f07dd..e4e2c7dfaa 100644
--- a/test/integration/rules/link-in-text-block/link-in-text-block.json
+++ b/test/integration/rules/link-in-text-block/link-in-text-block.json
@@ -14,5 +14,8 @@
     ["#pass-text-color"],
     ["#pass-same-colors"]
   ],
-  "incomplete": [["#incomplete-low-contrast-parent-has-gradient"]]
+  "incomplete": [
+    ["#incomplete-low-contrast-parent-has-gradient"],
+    ["#incomplete-pseudo-before"]
+  ]
 }