From b0ce56fff066d5b043946af876b711290cb8b17a Mon Sep 17 00:00:00 2001
From: Jean-Yves Moyen <jym@siteimprove.com>
Date: Wed, 17 Jun 2020 11:12:25 +0200
Subject: [PATCH 1/3] Treat kind attribute as enumerated

---
 .../src/common/applicability/video.ts           | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/packages/alfa-rules/src/common/applicability/video.ts b/packages/alfa-rules/src/common/applicability/video.ts
index 120d5fad8d..520d54f6fd 100644
--- a/packages/alfa-rules/src/common/applicability/video.ts
+++ b/packages/alfa-rules/src/common/applicability/video.ts
@@ -39,7 +39,22 @@ export function video(
                   Element.isElement,
                   and(
                     hasName("track"),
-                    hasAttribute("kind", equals(track.kind))
+                    (trackElement) =>
+                      trackElement
+                        .attribute("kind")
+                        .map(
+                          (kind) =>
+                            kind
+                              .enumerate(
+                                "subtitles",
+                                "captions",
+                                "descriptions",
+                                "chapters",
+                                "metadata"
+                              )
+                              .getOr("metadata") // invalid value default
+                        )
+                        .getOr("subtitles") === track.kind // missing value default
                   )
                 )
               )

From bafc7367d82bc05fc419014d3c5a0fe3c33b2a8e Mon Sep 17 00:00:00 2001
From: Jean-Yves Moyen <jym@siteimprove.com>
Date: Wed, 17 Jun 2020 11:15:19 +0200
Subject: [PATCH 2/3] Add link to specs in comment

---
 packages/alfa-rules/src/common/applicability/video.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/alfa-rules/src/common/applicability/video.ts b/packages/alfa-rules/src/common/applicability/video.ts
index 520d54f6fd..da72186c4e 100644
--- a/packages/alfa-rules/src/common/applicability/video.ts
+++ b/packages/alfa-rules/src/common/applicability/video.ts
@@ -42,6 +42,7 @@ export function video(
                     (trackElement) =>
                       trackElement
                         .attribute("kind")
+                        // @see https://html.spec.whatwg.org/multipage/media.html#attr-track-kind
                         .map(
                           (kind) =>
                             kind

From 1e24cd0f33491230ebe830611596fa53cd1f8e88 Mon Sep 17 00:00:00 2001
From: Jean-Yves Moyen <jym@siteimprove.com>
Date: Wed, 17 Jun 2020 11:27:40 +0200
Subject: [PATCH 3/3] Clean up

---
 packages/alfa-rules/src/common/applicability/video.ts | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/packages/alfa-rules/src/common/applicability/video.ts b/packages/alfa-rules/src/common/applicability/video.ts
index da72186c4e..f606d71cdc 100644
--- a/packages/alfa-rules/src/common/applicability/video.ts
+++ b/packages/alfa-rules/src/common/applicability/video.ts
@@ -8,11 +8,10 @@ import { Predicate } from "@siteimprove/alfa-predicate";
 import { isVisible } from "../predicate/is-visible";
 
 import { Question } from "../question";
-import { hasAttribute } from "../predicate/has-attribute";
 
 const { isElement, hasName, hasNamespace } = Element;
 const { filter, map, some } = Iterable;
-const { and, equals } = Predicate;
+const { and } = Predicate;
 
 export function video(
   document: Document,