Bug 1594743 - ensure that the keyboard audit does not interfere with other audit types. r=nchevobbe

Differential Revision: https://phabricator.services.mozilla.com/D52378

--HG--
extra : moz-landing-system : lando

devtools/server/actors/accessibility/accessible.js

@@ -526,12 +526,37 @@ const AccessibleActor = ActorClassWithSpec(accessibleSpec, {
       auditTypes = auditTypes.filter(auditType => types.includes(auditType));
     }
 
-    // More audit steps will be added here in the near future. In addition to
-    // colour contrast ratio we will add autits for to the missing names,
-    // invalid states, etc. (For example see bug 1518808).
-    this._auditing = Promise.all(
-      auditTypes.map(auditType => this._getAuditByType(auditType))
-    )
+    // For some reason keyboard checks for focus styling affect values (that are
+    // used by other types of checks (text names and values)) returned by
+    // accessible objects. This happens only when multiple checks are run at the
+    // same time (asynchronously) and the audit might return unexpected
+    // failures. We thus split the execution of the checks into two parts, first
+    // performing keyboard checks and only after the rest of the checks. See bug
+    // 1594743 for more detail.
+    let keyboardAuditResult;
+    const keyboardAuditIndex = auditTypes.indexOf(AUDIT_TYPE.KEYBOARD);
+    if (keyboardAuditIndex > -1) {
+      // If we are performing a keyboard audit, remove its value from the
+      // complete list and run it.
+      auditTypes.splice(keyboardAuditIndex, 1);
+      keyboardAuditResult = this._getAuditByType(AUDIT_TYPE.KEYBOARD);
+    }
+
+    this._auditing = Promise.resolve(keyboardAuditResult)
+      .then(keyboardResult => {
+        const audits = auditTypes.map(auditType =>
+          this._getAuditByType(auditType)
+        );
+
+        // If we are also performing a keyboard audit, add its type and its
+        // result back to the complete list of audits.
+        if (keyboardAuditIndex > -1) {
+          auditTypes.splice(keyboardAuditIndex, 0, AUDIT_TYPE.KEYBOARD);
+          audits.splice(keyboardAuditIndex, 0, keyboardResult);
+        }
+
+        return Promise.all(audits);
+      })
       .then(results => {
         if (this.isDefunct || this.isDestroyed) {
           return null;