fix(a11n): provide proper a11n for response example tabs (#7464)

- Update tabs to use <button> elements instead of <a>
- Add aria roles for tablist, tabs, and tabpanel
- Add aria attributes for additional a11y compliance and screen reader accessibility
- Replace ids with data-name attribute for tabpanels
- Add cypress test 7463 and update swos-63
- Move tabs test file to tests/a11y directory
- Rename test file to be more descriptive of what is being tested.
- Add id attributes to both tabs and tabpanels to leverage aria-controls and aria-labelledby attributes

Co-authored-by: Calvin Gonzalez <calvin.gonzalez@oddball.io>
Co-authored-by: Vladimir Gorej <vladimir.gorej@gmail.com>

Closes #7463
Refs #7350

src/core/components/model-example.jsx

@@ -1,6 +1,8 @@
 import React from "react"
 import PropTypes from "prop-types"
 import ImPropTypes from "react-immutable-proptypes"
+import cx from "classnames"
+import randomBytes from "randombytes"
 
 export default class ModelExample extends React.Component {
   static propTypes = {
@@ -31,11 +33,11 @@ export default class ModelExample extends React.Component {
     }
 
     this.state = {
-      activeTab: activeTab
+      activeTab,
     }
   }
 
-  activeTab =( e ) => {
+  activeTab = ( e ) => {
     let { target : { dataset : { name } } } = e
 
     this.setState({
@@ -58,42 +60,83 @@ export default class ModelExample extends React.Component {
     let { defaultModelExpandDepth } = getConfigs()
     const ModelWrapper = getComponent("ModelWrapper")
     const HighlightCode = getComponent("highlightCode")
+    const exampleTabId = randomBytes(5).toString("base64")
+    const examplePanelId = randomBytes(5).toString("base64")
+    const modelTabId = randomBytes(5).toString("base64")
+    const modelPanelId = randomBytes(5).toString("base64")
 
     let isOAS3 = specSelectors.isOAS3()
 
-    return <div className="model-example">
-      <ul className="tab">
-        <li className={ "tabitem" + ( this.state.activeTab === "example" ? " active" : "") }>
-          <a className="tablinks" data-name="example" onClick={ this.activeTab }>{isExecute ? "Edit Value" : "Example Value"}</a>
-        </li>
-        { schema ? <li className={ "tabitem" + ( this.state.activeTab === "model" ? " active" : "") }>
-          <a className={ "tablinks" + ( isExecute ? " inactive" : "" )} data-name="model" onClick={ this.activeTab }>
-            {isOAS3 ? "Schema" : "Model" }
-          </a>
-        </li> : null }
-      </ul>
-      <div>
-        {
-          this.state.activeTab === "example" ? (
-            example ? example : (
+    return (
+      <div className="model-example">
+        <ul className="tab" role="tablist">
+          <li className={cx("tabitem", { active: this.state.activeTab === "example" })} role="presentation">
+            <button
+              aria-controls={examplePanelId}
+              aria-selected={this.state.activeTab === "example"}
+              className="tablinks"
+              data-name="example"
+              id={exampleTabId}
+              onClick={ this.activeTab }
+              role="tab"
+            >
+              {isExecute ? "Edit Value" : "Example Value"}
+            </button>
+          </li>
+          { schema && (
+            <li className={cx("tabitem", { active: this.state.activeTab === "model" })} role="presentation">
+              <button
+                aria-controls={modelPanelId}
+                aria-selected={this.state.activeTab === "model"}
+                className={cx("tablinks", { inactive: isExecute })}
+                data-name="model"
+                id={modelTabId}
+                onClick={ this.activeTab }
+                role="tab"
+              >
+                {isOAS3 ? "Schema" : "Model" }
+              </button>
+            </li>
+          )}
+        </ul>
+        {this.state.activeTab === "example" && (
+          <div
+            aria-hidden={this.state.activeTab !== "example"}
+            aria-labelledby={exampleTabId}
+            data-name="examplePanel"
+            id={examplePanelId}
+            role="tabpanel"
+            tabIndex="0"
+          >
+            {example ? example : (
               <HighlightCode value="(no example available)" getConfigs={ getConfigs } />
-            )
-          ) : null
-        }
-        {
-          this.state.activeTab === "model" && <ModelWrapper schema={ schema }
-                                                     getComponent={ getComponent }
-                                                     getConfigs={ getConfigs }
-                                                     specSelectors={ specSelectors }
-                                                     expandDepth={ defaultModelExpandDepth }
-                                                     specPath={specPath}
-                                                     includeReadOnly = {includeReadOnly}
-                                                     includeWriteOnly = {includeWriteOnly}/>
+            )}
+          </div>
+        )}
 
-
-        }
+        {this.state.activeTab === "model" && (
+          <div
+            aria-hidden={this.state.activeTab === "example"}
+            aria-labelledby={modelTabId}
+            data-name="modelPanel"
+            id={modelPanelId}
+            role="tabpanel"
+            tabIndex="0"
+          >
+            <ModelWrapper
+              schema={ schema }
+              getComponent={ getComponent }
+              getConfigs={ getConfigs }
+              specSelectors={ specSelectors }
+              expandDepth={ defaultModelExpandDepth }
+              specPath={specPath}
+              includeReadOnly = {includeReadOnly}
+              includeWriteOnly = {includeWriteOnly}
+            />
+          </div>
+        )}
       </div>
-    </div>
+    )
   }
 
 }

test/e2e-cypress/tests/a11y/response-tabs.js

@@ -0,0 +1,35 @@
+describe("Response tab elements", () => {
+  describe("ModelExample within Operation", () => {
+    it("should render Example tabpanel by default", () => {
+      cy
+        .visit("/?url=/documents/petstore-expanded.openapi.yaml")
+        .get("#operations-default-addPet")
+        .click()
+        .get("div[data-name=examplePanel]")
+        .first()
+        .should("have.attr", "aria-hidden", "false")
+    })
+    it("should click Schema tab button and render Schema tabpanel for OpenAPI 3", () => {
+      cy
+        .visit("/?url=/documents/petstore-expanded.openapi.yaml")
+        .get("#operations-default-addPet")
+        .click()
+        .get("button.tablinks[data-name=model]")
+        .first()
+        .click()
+        .get("div[data-name=modelPanel]")
+        .first()
+        .should("have.attr", "aria-hidden", "false")
+    })
+    it("should click Model tab button and render Model tabpanel for OpenAPI 2", () => {
+      cy
+        .visit("/?url=/documents/petstore.swagger.yaml")
+        .get("#operations-pet-addPet")
+        .click()
+        .get("button.tablinks[data-name=model]")
+        .click()
+        .get("div[data-name=modelPanel]")
+        .should("have.attr", "aria-hidden", "false")
+    })
+  })
+})

test/e2e-cypress/tests/bugs/swos-63.js

@@ -19,7 +19,7 @@ describe("SWOS-63: Schema/Model labeling", () => {
         .visit("/?url=/documents/petstore-expanded.openapi.yaml")
         .get("#operations-default-findPets")
         .click()
-        .get("a.tablinks[data-name=model]")
+        .get("button.tablinks[data-name=model]")
         .contains("Schema")
     })
     it("should render `Models` for OpenAPI 2", () => {
@@ -28,7 +28,7 @@ describe("SWOS-63: Schema/Model labeling", () => {
         .get("section.models > h4")
         .get("#operations-pet-addPet")
         .click()
-        .get("a.tablinks[data-name=model]")
+        .get("button.tablinks[data-name=model]")
         .contains("Model")
     })
   })