From fe369f9f612ffa368d71dc48fe121fe0d3389b3a Mon Sep 17 00:00:00 2001
From: Maksim Sadym <sadym@chromium.org>
Date: Mon, 11 Nov 2024 17:55:10 +0100
Subject: [PATCH 1/4] RFC XXX: Add ?feature query parameter to testdriver.js

---
 rfcs/testdriver-features.md | 104 ++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 rfcs/testdriver-features.md
diff --git a/rfcs/testdriver-features.md b/rfcs/testdriver-features.md
new file mode 100644
index 00000000..9a1ad7af
--- /dev/null
+++ b/rfcs/testdriver-features.md
@@ -0,0 +1,104 @@
+# RFC XXX: Add `?feature` query parameter to `testdriver.js`
+
+## Summary
+
+This RFC is an alternative to [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212). It proposes adding a query parameter `?features` to `testdriver.js`. At the moment the only supported feature will be `bidi`, which will be used to enable the [testdriver BiDi API](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) for specific WPT tests, The supported features can be extended by other RFCs if required. The feature `bidi`, applicable to HTML and JS files, would let test runners choose between [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/blob/9c76757f5332678f9952f6ccb3824f62d30eca1f/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L644) and [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/blob/9c76757f5332678f9952f6ccb3824f62d30eca1f/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L736). This approach does not require all the browsers to implement WebDriver BiDi.
+
+[Prototype](https://github.com/web-platform-tests/wpt/pull/48622).
+
+## Background
+
+[RFC 185](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) proposes adding BiDi support to  `testdriver.js`, which involves using [WebDriverBidiProtocol](https://github.com/web-platform-tests/wpt/blob/9c76757f5332678f9952f6ccb3824f62d30eca1f/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L736) instead of [WebDriverProtocol](https://github.com/web-platform-tests/wpt/blob/9c76757f5332678f9952f6ccb3824f62d30eca1f/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L644) for test runners that use the WebDriver protocol. However, this change could cause regressions in tests that don't use the testdriver BiDi API due to unintended side effects of the transport change. To address this, the query parameter `?features=bidi` in `testdriver.js` will inform the test runner whether the given test requires the testdriver BiDi API, allowing the runner to choose the appropriate transport, if the default one does not support BiDi protocol parts.
+
+If at a certain point all the browsers implement testdriver BiDi and enable it by default, this flag can be deprecated.
+
+## Details
+
+### Examples
+
+[html test](https://github.com/web-platform-tests/wpt/blob/9395d384f5c69a9a3a7fc4de04249f77500b2d3f/infrastructure/webdriver/bidi/subscription.html#L3)
+```javascript
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Test console log are present</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/testdriver.js?features=bidi"></script>
+<script src="/resources/testdriver-vendor.js"></script>
+<script>
+    promise_test(async () => {
+        const some_message = "SOME MESSAGE";
+        // Subscribe to `log.entryAdded` BiDi events. This will not add a listener to the page.
+        await test_driver.bidi.log.entry_added.subscribe();
+        // Add a listener for the log.entryAdded event. This will not subscribe to the event, so the subscription is
+        // required before. The cleanup is done automatically after the test is finished.
+        const log_entry_promise = test_driver.bidi.log.entry_added.once();
+        // Emit a console.log message.
+        // Note: Lint rule is disabled in `lint.ignore` file.
+        console.log(some_message);
+        // Wait for the log.entryAdded event to be received.
+        const event = await log_entry_promise;
+        // Assert the log.entryAdded event has the expected message.
+        assert_equals(event.args.length, 1);
+        const event_message = event.args[0];
+        assert_equals(event_message.value, some_message);
+    }, "Assert testdriver can subscribe and receive events");
+```
+
+```javascript
+// META: script=/resources/testdriver.js?features=bidi
+
+'use strict';
+
+promise_test(async () => {
+    const some_message = "SOME MESSAGE";
+     // Subscribe to `log.entryAdded` BiDi events. This will not add a listener to the page.
+    await test_driver.bidi.log.entry_added.subscribe();
+    // Add a listener for the log.entryAdded event. This will not subscribe to the event, so the subscription is
+    // required before. The cleanup is done automatically after the test is finished.
+    const log_entry_promise = test_driver.bidi.log.entry_added.once();
+    // Emit a console.log message.
+    // Note: Lint rule is disabled in `lint.ignore` file.
+    console.log(some_message);
+    // Wait for the log.entryAdded event to be received.
+    const event = await log_entry_promise;
+    // Assert the log.entryAdded event has the expected message.
+    assert_equals(event.args.length, 1);
+    const event_message = event.args[0];
+    assert_equals(event_message.value, some_message);
+}, "Assert testdriver can subscribe and receive events");
+```
+
+### Required changes
+
+#### Features
+
+The `testrdriver_features` is a list of values of query parameters with the name `feature`, used when the `testdriver.js` is imported. It has to be passed from `SourceFile` through `TestharnessTest` to `Test`, where it can be consumed by the specific test runners.
+
+`testdriver.js` will provide or not the `bidi` domain based on having or not the `feature=bidi` query parameter when it was included.
+
+The `feature` query parameter can be set when `testdriver.js` is included either in `.html` or `.js`. The [SourceFile](https://github.com/web-platform-tests/wpt/blob/9395d384f5c69a9a3a7fc4de04249f77500b2d3f/tools/manifest/sourcefile.py#L503) collects the features in the `testrdriver_features` list and passes it to the [TestharnessTest](https://github.com/web-platform-tests/wpt/blob/9395d384f5c69a9a3a7fc4de04249f77500b2d3f/tools/manifest/item.py#L169) object. The `TestharnessTest` object then passes the `testrdriver_features` property to the `Test` object.
+
+The test runner can use the `Test`’s `testrdriver_features` property to determine whether to enable BiDi support for the test.
+
+Even though the `TestExecutor` needs information about whether to activate BiDi or not at `connect`, which happens before the runner receives the test to run, the configuration can be done at the point [the browser is configured](https://github.com/web-platform-tests/wpt/pull/48618/files#diff-0df24b5b583c460182e687f7dc7a6a79dd2cd3389bc4a96f48483f60fceb51f7R272). This data can be used later by the specific executor implementation to [decide which protocol to use](https://github.com/web-platform-tests/wpt/pull/48618/files#diff-c2f15328bc1ddfa8fb93c09ae41651e2bcfdad4f257932263a3e92c3f8deffceR248).
+
+#### Lint rules
+
+Some lint rules has to be added to verify is used correctly:
+* It is unique per test file.
+* It has the correct value (either `true` or `false`).
+
+### Deprecating of the `require_webdriver_bidi` metadata tag
+
+Expectations are that eventually all the implementations would support BiDi either via WebDriverBiDi, or via implementation-specific bindings. At that point, the `require_webdriver_bidi` metadata tag can be deprecated. This can be done by simply removing the tag.
+
+## Risks
+
+### Having metadata in the Test is not sufficient
+
+`TestExecutor` needs information about whether to activate BiDi or not at `connect`, which happens before the runner receives the test metadata. This can be addressed by passing the data to implementation-specific `TestharnessExecutor` via the implementation-specific `BrowserSettings` and  like in the [example](https://github.com/web-platform-tests/wpt/pull/48618/files#diff-0df24b5b583c460182e687f7dc7a6a79dd2cd3389bc4a96f48483f60fceb51f7R269).
+
+## Alternatives considered
+
+List of alternatives is in the [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212).

From 5339c7899aa57d18ac683fd5968c6227f47a85f4 Mon Sep 17 00:00:00 2001
From: Maksim Sadym <sadym@chromium.org>
Date: Mon, 11 Nov 2024 18:02:19 +0100
Subject: [PATCH 2/4] update

---
 rfcs/testdriver-features.md | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/rfcs/testdriver-features.md b/rfcs/testdriver-features.md
index 9a1ad7af..833e109e 100644
--- a/rfcs/testdriver-features.md
+++ b/rfcs/testdriver-features.md
@@ -1,16 +1,16 @@
-# RFC XXX: Add `?feature` query parameter to `testdriver.js`
+# RFC 214: Add `?feature` query parameter to `testdriver.js`
 
 ## Summary
 
-This RFC is an alternative to [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212). It proposes adding a query parameter `?features` to `testdriver.js`. At the moment the only supported feature will be `bidi`, which will be used to enable the [testdriver BiDi API](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) for specific WPT tests, The supported features can be extended by other RFCs if required. The feature `bidi`, applicable to HTML and JS files, would let test runners choose between [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/blob/9c76757f5332678f9952f6ccb3824f62d30eca1f/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L644) and [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/blob/9c76757f5332678f9952f6ccb3824f62d30eca1f/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L736). This approach does not require all the browsers to implement WebDriver BiDi.
+This RFC is an alternative to [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212). It proposes adding a query parameter `?feature` to `testdriver.js`. At the moment the only supported feature will be `bidi`, which will be used to enable the [testdriver BiDi API](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) for specific WPT tests. The feature `bidi`, applicable to HTML and JS files, would let test runners choose between [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L587) and [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L679). This approach does not require all the browsers to implement WebDriver BiDi.
 
-[Prototype](https://github.com/web-platform-tests/wpt/pull/48622).
+The list of supported features can be extended by other RFCs if required.
 
-## Background
+[Prototype](TODO).
 
-[RFC 185](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) proposes adding BiDi support to  `testdriver.js`, which involves using [WebDriverBidiProtocol](https://github.com/web-platform-tests/wpt/blob/9c76757f5332678f9952f6ccb3824f62d30eca1f/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L736) instead of [WebDriverProtocol](https://github.com/web-platform-tests/wpt/blob/9c76757f5332678f9952f6ccb3824f62d30eca1f/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L644) for test runners that use the WebDriver protocol. However, this change could cause regressions in tests that don't use the testdriver BiDi API due to unintended side effects of the transport change. To address this, the query parameter `?features=bidi` in `testdriver.js` will inform the test runner whether the given test requires the testdriver BiDi API, allowing the runner to choose the appropriate transport, if the default one does not support BiDi protocol parts.
+## Background
 
-If at a certain point all the browsers implement testdriver BiDi and enable it by default, this flag can be deprecated.
+[RFC 185](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) proposes adding BiDi support to  `testdriver.js`, which involves using [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L587) instead of [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L679) for test runners that use the WebDriver protocol. However, this change could cause regressions in tests that don't use the testdriver BiDi API due to unintended side effects of the transport change. To address this, the query parameter `?feature=bidi` in `testdriver.js` will inform the test runner whether the given test requires the testdriver BiDi API, allowing the runner to choose the appropriate transport, if the default one does not support BiDi protocol parts.
 
 ## Details
 
@@ -23,7 +23,7 @@ If at a certain point all the browsers implement testdriver BiDi and enable it b
 <title>Test console log are present</title>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-<script src="/resources/testdriver.js?features=bidi"></script>
+<script src="/resources/testdriver.js?feature=bidi"></script>
 <script src="/resources/testdriver-vendor.js"></script>
 <script>
     promise_test(async () => {
@@ -46,7 +46,7 @@ If at a certain point all the browsers implement testdriver BiDi and enable it b
 ```
 
 ```javascript
-// META: script=/resources/testdriver.js?features=bidi
+// META: script=/resources/testdriver.js?feature=bidi
 
 'use strict';
 

From f9bf2325b69e6a4465dfacede58890f5a3347d79 Mon Sep 17 00:00:00 2001
From: Maksim Sadym <sadym@chromium.org>
Date: Tue, 12 Nov 2024 16:00:40 +0100
Subject: [PATCH 3/4] extend

---
 rfcs/testdriver-features.md | 40 +++++++++++++++++--------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/rfcs/testdriver-features.md b/rfcs/testdriver-features.md
index 833e109e..f388f682 100644
--- a/rfcs/testdriver-features.md
+++ b/rfcs/testdriver-features.md
@@ -2,15 +2,15 @@
 
 ## Summary
 
-This RFC is an alternative to [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212). It proposes adding a query parameter `?feature` to `testdriver.js`. At the moment the only supported feature will be `bidi`, which will be used to enable the [testdriver BiDi API](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) for specific WPT tests. The feature `bidi`, applicable to HTML and JS files, would let test runners choose between [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L587) and [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L679). This approach does not require all the browsers to implement WebDriver BiDi.
+This RFC is an alternative to [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212) providing a more generic and extendable solution. It proposes adding a query parameter `?feature` to `testdriver.js` and adding a `testdriver_feature` property to the [TestgarnessTest](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-8f280b64b0700ab9b4b343adabc7ff4d5ea4b1f45cb6c4bd7f50a19b21ebdb8cR169) . At the moment the only supported feature will be `bidi`, which will be used to enable the [testdriver BiDi API](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) for specific WPT tests. The feature `bidi`, applicable to HTML and JS files, would let test runners choose between [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-c2f15328bc1ddfa8fb93c09ae41651e2bcfdad4f257932263a3e92c3f8deffceR277) and [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-c2f15328bc1ddfa8fb93c09ae41651e2bcfdad4f257932263a3e92c3f8deffceR279). This approach does not require all the browsers to implement WebDriver BiDi.
 
-The list of supported features can be extended by other RFCs if required.
+This approach is preferable over the [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212), as it is more ergonomic and supports future extensions ergonomically. The list of supported features can be extended when required.
 
-[Prototype](TODO).
+[Prototype](https://github.com/web-platform-tests/wpt/pull/49122).
 
 ## Background
 
-[RFC 185](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) proposes adding BiDi support to  `testdriver.js`, which involves using [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L587) instead of [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L679) for test runners that use the WebDriver protocol. However, this change could cause regressions in tests that don't use the testdriver BiDi API due to unintended side effects of the transport change. To address this, the query parameter `?feature=bidi` in `testdriver.js` will inform the test runner whether the given test requires the testdriver BiDi API, allowing the runner to choose the appropriate transport, if the default one does not support BiDi protocol parts.
+[RFC 185](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) proposes adding BiDi support to  `testdriver.js`, which involves using [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L587) instead of [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L679) for test runners that use the WebDriver protocol. However, this change could cause regressions in tests that don't use the testdriver BiDi API due to unintended side effects of the transport change.
 
 ## Details
 
@@ -71,34 +71,30 @@ promise_test(async () => {
 
 ### Required changes
 
-#### Features
+#### `testrdriver_features`
 
-The `testrdriver_features` is a list of values of query parameters with the name `feature`, used when the `testdriver.js` is imported. It has to be passed from `SourceFile` through `TestharnessTest` to `Test`, where it can be consumed by the specific test runners.
+The `testrdriver_features` is a list of values of query parameters with the name `feature`, used when the `testdriver.js` was imported.
 
-`testdriver.js` will provide or not the `bidi` domain based on having or not the `feature=bidi` query parameter when it was included.
+#### Test driver
 
-The `feature` query parameter can be set when `testdriver.js` is included either in `.html` or `.js`. The [SourceFile](https://github.com/web-platform-tests/wpt/blob/9395d384f5c69a9a3a7fc4de04249f77500b2d3f/tools/manifest/sourcefile.py#L503) collects the features in the `testrdriver_features` list and passes it to the [TestharnessTest](https://github.com/web-platform-tests/wpt/blob/9395d384f5c69a9a3a7fc4de04249f77500b2d3f/tools/manifest/item.py#L169) object. The `TestharnessTest` object then passes the `testrdriver_features` property to the `Test` object.
+The `testdriver.js` checks if the `?feature=bidi` query parameter was included using [document.currentScript.src](https://developer.mozilla.org/en-US/docs/Web/API/Document/currentScript) like in the [prototype](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-1fe2b624679a3150e5c86f84682c5901b715dad750096a524e8cb23939e5590fR16). If `bidi` was not enabled, a [descriptive error will be thrown](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-1fe2b624679a3150e5c86f84682c5901b715dad750096a524e8cb23939e5590fR89-R92).
 
-The test runner can use the `Test`’s `testrdriver_features` property to determine whether to enable BiDi support for the test.
+#### Test executor
 
-Even though the `TestExecutor` needs information about whether to activate BiDi or not at `connect`, which happens before the runner receives the test to run, the configuration can be done at the point [the browser is configured](https://github.com/web-platform-tests/wpt/pull/48618/files#diff-0df24b5b583c460182e687f7dc7a6a79dd2cd3389bc4a96f48483f60fceb51f7R272). This data can be used later by the specific executor implementation to [decide which protocol to use](https://github.com/web-platform-tests/wpt/pull/48618/files#diff-c2f15328bc1ddfa8fb93c09ae41651e2bcfdad4f257932263a3e92c3f8deffceR248).
+The `feature` query parameter can be set when `testdriver.js` is included either in `.html` or `.js`. The test runner can use the `Test`’s `testrdriver_features` property to determine whether to enable BiDi support for the test.
 
-#### Lint rules
-
-Some lint rules has to be added to verify is used correctly:
-* It is unique per test file.
-* It has the correct value (either `true` or `false`).
-
-### Deprecating of the `require_webdriver_bidi` metadata tag
-
-Expectations are that eventually all the implementations would support BiDi either via WebDriverBiDi, or via implementation-specific bindings. At that point, the `require_webdriver_bidi` metadata tag can be deprecated. This can be done by simply removing the tag.
+Even though the `TestExecutor` needs information about whether to activate BiDi or not at `connect`, which happens before the runner receives the test to run, the configuration can be done at the point [the browser is configured](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-0df24b5b583c460182e687f7dc7a6a79dd2cd3389bc4a96f48483f60fceb51f7R275). This data can be used later by the specific executor implementation to [decide which protocol to use](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-0df24b5b583c460182e687f7dc7a6a79dd2cd3389bc4a96f48483f60fceb51f7R275).
 
 ## Risks
 
-### Having metadata in the Test is not sufficient
+### Having `testrdriver_features` in the `Test` is not sufficient
 
-`TestExecutor` needs information about whether to activate BiDi or not at `connect`, which happens before the runner receives the test metadata. This can be addressed by passing the data to implementation-specific `TestharnessExecutor` via the implementation-specific `BrowserSettings` and  like in the [example](https://github.com/web-platform-tests/wpt/pull/48618/files#diff-0df24b5b583c460182e687f7dc7a6a79dd2cd3389bc4a96f48483f60fceb51f7R269).
+`TestExecutor` needs information about whether to activate BiDi or not at `connect`, which happens before the runner receives the test metadata. This can be addressed by passing the data to implementation-specific `TestharnessExecutor` via the implementation-specific `BrowserSettings` and  like in the [example](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-0df24b5b583c460182e687f7dc7a6a79dd2cd3389bc4a96f48483f60fceb51f7R269).
 
 ## Alternatives considered
 
-List of alternatives is in the [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212).
+List of other alternatives is in the [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212).
+
+### Always provide `bidi` API in testdriver
+
+In this alternative, the testdriver does not raise an error if the bidi feature was not enabled.This creates a risk of potential false-negative test results, if the test author forgets to add the `feature=bidi` and check the test only on the browser implementation which supports WebDriver BiDi by-default, regardless of the feature.

From dfb51ed91dbcddf9c9ca52be5695468040200af1 Mon Sep 17 00:00:00 2001
From: Maksim Sadym <sadym@chromium.org>
Date: Tue, 12 Nov 2024 16:33:38 +0100
Subject: [PATCH 4/4] sync with doc

---
 rfcs/testdriver-features.md | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/rfcs/testdriver-features.md b/rfcs/testdriver-features.md
index f388f682..108c5fd7 100644
--- a/rfcs/testdriver-features.md
+++ b/rfcs/testdriver-features.md
@@ -1,8 +1,8 @@
-# RFC 214: Add `?feature` query parameter to `testdriver.js`
+# RFC 214: Add testdriver features
 
 ## Summary
 
-This RFC is an alternative to [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212) providing a more generic and extendable solution. It proposes adding a query parameter `?feature` to `testdriver.js` and adding a `testdriver_feature` property to the [TestgarnessTest](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-8f280b64b0700ab9b4b343adabc7ff4d5ea4b1f45cb6c4bd7f50a19b21ebdb8cR169) . At the moment the only supported feature will be `bidi`, which will be used to enable the [testdriver BiDi API](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) for specific WPT tests. The feature `bidi`, applicable to HTML and JS files, would let test runners choose between [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-c2f15328bc1ddfa8fb93c09ae41651e2bcfdad4f257932263a3e92c3f8deffceR277) and [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-c2f15328bc1ddfa8fb93c09ae41651e2bcfdad4f257932263a3e92c3f8deffceR279). This approach does not require all the browsers to implement WebDriver BiDi.
+This RFC is an alternative to [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212) providing more generic and extendable solution. It proposes adding a query parameter `?feature` to `testdriver.js` and adding a `testdriver_features` property to the [TestharnessTest](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-8f280b64b0700ab9b4b343adabc7ff4d5ea4b1f45cb6c4bd7f50a19b21ebdb8cR169). At the moment the only supported feature will be `bidi`, which will be used to enable the [testdriver BiDi API](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) for specific WPT tests. The feature `bidi`, applicable to HTML and JS files, would let test runners choose between [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-c2f15328bc1ddfa8fb93c09ae41651e2bcfdad4f257932263a3e92c3f8deffceR277) and [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-c2f15328bc1ddfa8fb93c09ae41651e2bcfdad4f257932263a3e92c3f8deffceR279). This approach does not require all the browsers to implement WebDriver BiDi.
 
 This approach is preferable over the [RFC 212](https://github.com/web-platform-tests/rfcs/pull/212), as it is more ergonomic and supports future extensions ergonomically. The list of supported features can be extended when required.
 
@@ -10,7 +10,7 @@ This approach is preferable over the [RFC 212](https://github.com/web-platform-t
 
 ## Background
 
-[RFC 185](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) proposes adding BiDi support to  `testdriver.js`, which involves using [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L587) instead of [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L679) for test runners that use the WebDriver protocol. However, this change could cause regressions in tests that don't use the testdriver BiDi API due to unintended side effects of the transport change.
+[RFC 185](https://github.com/web-platform-tests/rfcs/blob/master/rfcs/testdriver_bidi.md) proposes adding BiDi support to  `testdriver.js`, which involves using [**WebDriverProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L587) instead of [**WebDriverBidiProtocol**](https://github.com/web-platform-tests/wpt/blob/f54cd920024da0857fdc5b036f16a7d1fd8792fd/tools/wptrunner/wptrunner/executors/executorwebdriver.py#L679) for test runners that use the WebDriver protocol. However, this change could cause regressions in tests that don't use the testdriver BiDi API due to unintended side effects of the transport change. This RFC proposes a solution for the issue.
 
 ## Details
 
@@ -71,17 +71,15 @@ promise_test(async () => {
 
 ### Required changes
 
-#### `testrdriver_features`
+#### Configure testdriver.js based on the ?feature flag
 
-The `testrdriver_features` is a list of values of query parameters with the name `feature`, used when the `testdriver.js` was imported.
+The `testdriver.js` checks if the `?feature=bidi` query parameter was included using [document.currentScript.src](https://developer.mozilla.org/en-US/docs/Web/API/Document/currentScript) like in the [prototype](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-1fe2b624679a3150e5c86f84682c5901b715dad750096a524e8cb23939e5590fR16). If `bidi` was not enabled, a [descriptive error will be thrown](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-1fe2b624679a3150e5c86f84682c5901b715dad750096a524e8cb23939e5590fR22).
 
-#### Test driver
+#### Add `testrdriver_features` to TestharnessTest
 
-The `testdriver.js` checks if the `?feature=bidi` query parameter was included using [document.currentScript.src](https://developer.mozilla.org/en-US/docs/Web/API/Document/currentScript) like in the [prototype](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-1fe2b624679a3150e5c86f84682c5901b715dad750096a524e8cb23939e5590fR16). If `bidi` was not enabled, a [descriptive error will be thrown](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-1fe2b624679a3150e5c86f84682c5901b715dad750096a524e8cb23939e5590fR89-R92).
+This RFC proposes adding `testrdriver_features` to [`TestharnessTest`](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-8f280b64b0700ab9b4b343adabc7ff4d5ea4b1f45cb6c4bd7f50a19b21ebdb8cR169) so that executors can get the list of features declared by a test. The list is populated by parsing the `feature` query param from the `testdriver.js` imports used by a test. Currently, only the `bidi` feature is supported.
 
-#### Test executor
-
-The `feature` query parameter can be set when `testdriver.js` is included either in `.html` or `.js`. The test runner can use the `Test`’s `testrdriver_features` property to determine whether to enable BiDi support for the test.
+#### (implementation-specific) Set up WebDriver BiDi in the test executor if needed
 
 Even though the `TestExecutor` needs information about whether to activate BiDi or not at `connect`, which happens before the runner receives the test to run, the configuration can be done at the point [the browser is configured](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-0df24b5b583c460182e687f7dc7a6a79dd2cd3389bc4a96f48483f60fceb51f7R275). This data can be used later by the specific executor implementation to [decide which protocol to use](https://github.com/web-platform-tests/wpt/pull/49122/files#diff-0df24b5b583c460182e687f7dc7a6a79dd2cd3389bc4a96f48483f60fceb51f7R275).
 
