Tests: Ensure whitespace appears in assertEqualHTML tests #10765

sirreal · 2026-01-20T12:09:27Z

Ensure that leading text whitespace is included in assertEqualHTML comparisons. See the Trac ticket description:

Some leading whitespace is trimmed from text nodes resulting in incorrect assertions like the following (passes, but should not):
$this->assertEqualHTML(
  "<p> x</p>",
  "<p>\nx</p>"
);
The following tree is constructed by build_visual_html_tree() in both cases:
<p>
  "x"
The expected trees are:
<p>
  " x"
<p>
  "
x"

Trac ticket: https://core.trac.wordpress.org/ticket/64531

This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

github-actions · 2026-01-20T12:15:37Z

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sirreal · 2026-01-20T12:27:53Z

I've pushed commit 9f672ba that updates a test to add the whitespace inside block delimiters.

This is a good example for discussion, I'd like to hear other opinions: @ockham @dmsnell

sirreal · 2026-01-20T14:37:48Z

tests/phpunit/includes/build-visual-html-tree.php

 			case '#text':
 				$text_content = $processor->get_modifiable_text();
-				if ( '' === trim( $text_content, " \f\t\r\n" ) ) {
+				if ( '' === $text_content ) {


This was the main problem, it effectively eliminated whitespace text completely, and leading whitespace from existing text nodes.

Why was this added in the first place? The trim() here occurs after decoding, meaning that any raw markup would have already been processed and whitespace normalized.

It was introduced as part of block delimiters appearing in the HTML tree. That change is not open source, this was largely developed in another project before being proposed for Core.

sirreal · 2026-01-20T14:40:28Z

I was surprised when whitespace wasn't detected recently but didn't think to look further. This explains it and the changes in the scripts tests are important.

sirreal · 2026-01-20T14:42:25Z

If we consider block delimiters as analogous to HTML tags, then it makes complete sense to preserve their inner whitespace. I'm more and more convinced that it should be preserved.

sirreal · 2026-01-20T14:46:29Z

tests/phpunit/tests/dependencies/scripts.php

+		$expected = "<script src='/main-script-d4.js' id='main-script-d4-js' data-wp-strategy='defer'></script>";
 		$this->assertEqualHTMLScriptTagById( $expected, $output, 'Scripts registered as defer but that have all dependents with no strategy, should become blocking (no strategy).' );


It may seem surprising that this assertion removes a trailing newline. This is using assertEqualHTMLScriptTagById() which matches the script tag, so a trailing newline will never be expected.

assertEqualHTMLScriptTagById() could probably trim its input, but it seems fine to just clean things up.

github-actions · 2026-01-20T14:50:00Z

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…ages The diff in the HTML is already presented by these tests. Printing again just introduces more noise.

assertEqualHTML already displays HTML differences

This reverts commit 23e18f7.

sirreal · 2026-01-20T16:43:19Z

Commit 951307e is informative.

It's a bit surprising because HTML is being compared with rendered block markup. This includes odd whitespace combinations like <div>\n\t\n\t<div> which is caused by whitespace around block-delimiter contents (which are removed) and rendered block contents. Many code editors (mine included) are configured to remove trailing whitespace, which makes it tricky to actually print \t\n inside the block markup (and I used the character reference 	).

diff --git a/tests/phpunit/tests/blocks/wpBlock.php b/tests/phpunit/tests/blocks/wpBlock.php
index b3c11ad084386..85fa6e7151d46 100644
--- a/tests/phpunit/tests/blocks/wpBlock.php
+++ b/tests/phpunit/tests/blocks/wpBlock.php
@@ -387,13 +387,20 @@ public function data_provider_test_render_enqueues_scripts_and_styles(): array {
 			'all_printed'                             => array(
 				'set_up'                  => null,
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<p class="dynamic">Hello World!</p>
-						<div class="static-child">Last child</div>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+&#x9;
+	<div class="static-child">First child</div>
+&#x9;
+	<p class="dynamic">Hello World!</p>
+&#x9;
+	<div class="static-child">Last child</div>
+&#x9;
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'static-child-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module', 'dynamic-view-script-module' ),
@@ -414,13 +421,20 @@ static function ( $content ) {
 					);
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<p class="dynamic filtered">Hello World!</p>
-						<div class="static-child">Last child</div>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+&#x9;
+	<div class="static-child">First child</div>
+&#x9;
+	<p class="dynamic filtered">Hello World!</p>
+&#x9;
+	<div class="static-child">Last child</div>
+&#x9;
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'dynamic-extra', 'static-child-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module', 'dynamic-view-script-module' ),
@@ -430,12 +444,20 @@ static function ( $content ) {
 					add_filter( 'render_block_core/dynamic', '__return_empty_string' );
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<div class="static-child">Last child</div>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+&#x9;
+	<div class="static-child">First child</div>
+&#x9;
+&#x9;
+&#x9;
+	<div class="static-child">Last child</div>
+&#x9;
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'static-child-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module' ),
@@ -456,12 +478,20 @@ static function ( $enqueue, $block_name ) {
 					);
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<div class="static-child">Last child</div>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+&#x9;
+	<div class="static-child">First child</div>
+&#x9;
+&#x9;
+&#x9;
+	<div class="static-child">Last child</div>
+&#x9;
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'static-child-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module', 'dynamic-view-script-module' ),
@@ -488,11 +518,16 @@ static function ( $content ) {
 					add_filter( 'render_block_core/static-child', '__return_empty_string' );
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<p class="dynamic">Hello World!</p>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+&#x9;
+	<p class="dynamic">Hello World!</p>
+&#x9;
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'dynamic-view-script-module' ),
@@ -512,12 +547,18 @@ static function ( $content ) {
 					);
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<p class="dynamic">Hello World!</p>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+&#x9;
+	<div class="static-child">First child</div>
+&#x9;
+	<p class="dynamic">Hello World!</p>
+&#x9;
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'static-child-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module', 'dynamic-view-script-module' ),

A simple alternative in this case is to remove the tabs from the block markup in the test.

sirreal · 2026-01-20T16:50:28Z

Here's a similar diff of the test fix without the block indentation (commit 29faaf5):

diff --git a/tests/phpunit/tests/blocks/wpBlock.php b/tests/phpunit/tests/blocks/wpBlock.php
index b3c11ad084..ae067e7d79 100644
--- a/tests/phpunit/tests/blocks/wpBlock.php
+++ b/tests/phpunit/tests/blocks/wpBlock.php
@@ -371,13 +371,13 @@ class Tests_Blocks_wpBlock extends WP_UnitTestCase {
 		$block_markup = <<<'HTML'
 <!-- wp:static -->
 <div class="static">
-	<!-- wp:static-child -->
-	<div class="static-child">First child</div>
-	<!-- /wp:static-child -->
-	<!-- wp:dynamic /-->
-	<!-- wp:static-child -->
-	<div class="static-child">Last child</div>
-	<!-- /wp:static-child -->
+<!-- wp:static-child -->
+<div class="static-child">First child</div>
+<!-- /wp:static-child -->
+<!-- wp:dynamic /-->
+<!-- wp:static-child -->
+<div class="static-child">Last child</div>
+<!-- /wp:static-child -->
 </div>
 <!-- /wp:static -->
 HTML;
@@ -387,13 +387,20 @@ HTML;
 			'all_printed'                             => array(
 				'set_up'                  => null,
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<p class="dynamic">Hello World!</p>
-						<div class="static-child">Last child</div>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+
+<div class="static-child">First child</div>
+
+<p class="dynamic">Hello World!</p>
+
+<div class="static-child">Last child</div>
+
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'static-child-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module', 'dynamic-view-script-module' ),
@@ -414,13 +421,20 @@ HTML;
 					);
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<p class="dynamic filtered">Hello World!</p>
-						<div class="static-child">Last child</div>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+
+<div class="static-child">First child</div>
+
+<p class="dynamic filtered">Hello World!</p>
+
+<div class="static-child">Last child</div>
+
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'dynamic-extra', 'static-child-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module', 'dynamic-view-script-module' ),
@@ -430,12 +444,20 @@ HTML;
 					add_filter( 'render_block_core/dynamic', '__return_empty_string' );
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<div class="static-child">Last child</div>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+
+<div class="static-child">First child</div>
+
+
+
+<div class="static-child">Last child</div>
+
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'static-child-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module' ),
@@ -456,12 +478,20 @@ HTML;
 					);
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<div class="static-child">Last child</div>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+
+<div class="static-child">First child</div>
+
+
+
+<div class="static-child">Last child</div>
+
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'static-child-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module', 'dynamic-view-script-module' ),
@@ -488,11 +518,16 @@ HTML;
 					add_filter( 'render_block_core/static-child', '__return_empty_string' );
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<p class="dynamic">Hello World!</p>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+
+<p class="dynamic">Hello World!</p>
+
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'dynamic-view-script-module' ),
@@ -512,12 +547,18 @@ HTML;
 					);
 				},
 				'block_markup'            => $block_markup,
-				'expected_rendered_block' => '
-					<div class="static">
-						<div class="static-child">First child</div>
-						<p class="dynamic">Hello World!</p>
-					</div>
-				',
+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+
+<div class="static-child">First child</div>
+
+<p class="dynamic">Hello World!</p>
+
+</div>
+
+HTML
+				,
 				'expected_styles'         => array( 'static-view-style', 'static-child-view-style', 'dynamic-view-style' ),
 				'expected_scripts'        => array( 'static-view-script', 'static-child-view-script', 'dynamic-view-script' ),
 				'expected_script_modules' => array( 'static-view-script-module', 'static-child-view-script-module', 'dynamic-view-script-module' ),

dmsnell · 2026-01-20T20:31:58Z

tests/phpunit/includes/build-visual-html-tree.php

 			case '#text':
 				$text_content = $processor->get_modifiable_text();
-				if ( '' === trim( $text_content, " \f\t\r\n" ) ) {
+				if ( '' === $text_content ) {


Why was this added in the first place? The trim() here occurs after decoding, meaning that any raw markup would have already been processed and whitespace normalized.

tests/phpunit/includes/build-visual-html-tree.php

dmsnell · 2026-01-20T20:39:03Z

tests/phpunit/tests/blocks/wpBlock.php

+				'expected_rendered_block' => <<<'HTML'
+
+<div class="static">
+


I’m not sure how to think through this, and I think you are alluding to it in how we split blocks from the HTML, but is this right? It seems to be producing two newlines which I wouldn’t have expected.

Also, the test code itself performs an initial trim() on the supplied test data. Could that be making these more confusing than they need to be. That @todo looks like a good candidate for WP_Block_Processor::extract_full_block_and_advance()

// test_render_enqueues_scripts_and_styles:L670 // TODO: Why not use do_blocks() instead? $parsed_blocks = parse_blocks( trim( $block_markup ) );

I’m not sure how to think through this, and I think you are alluding to it in how we split blocks from the HTML, but is this right? It seems to be producing two newlines which I wouldn’t have expected.

The block markup is this (after removing leading whitespace in this PR):

 <div class="static">  <div class="static-child">First child</div>    <div class="static-child">Last child</div>  </div> 

Rendering removes the block delimiters (and replaces the registered dynamic block), but preserves everything else. The result is this:

<div class="static"> <div class="static-child">First child</div> <p class="dynamic">Hello World!</p> <div class="static-child">Last child</div> </div>

Before removing the indentation, this is what caused the \n\t\n sequences (whitespace characters added for clarity):

␊ ␉ <div class="static">␊ ␉ ␊ ␉ <div class="static-child">First child</div>␊ ␉ ␊ ␉ ␊ ␉ ␊ ␉ <div class="static-child">Last child</div>␊ ␉ ␊ ␉ </div>␊ 

Becomes:

␊ ␉ <div class="static">␊ ␉ ␊ ␉ <div class="static-child">First child</div>␊ ␉ ␊ ␉ <p class="dynamic">Hello World!</p>␊ ␉ ␊ ␉ <div class="static-child">Last child</div>␊ ␉ ␊ ␉ </div>␊

I've noticed here that the indentation was inconsistent, with the static block's contents being indented, but static-child block's content remains at the same indentation:

wordpress-develop/tests/phpunit/tests/blocks/wpBlock.php

Lines 371 to 383 in 6ba48db

$block_markup = '



<div class="static">



<div class="static-child">First child</div>







<div class="static-child">Last child</div>



</div>



';

sirreal added 4 commits January 20, 2026 12:59

Fix typo in comment

11e758e

Do not trim leading text node whitespace

84c65af

Update test without leading whitespace, use nowdoc

d483c8d

Add test for https://core.trac.wordpress.org/ticket/64531

72e7c40

sirreal added 2 commits January 20, 2026 13:24

Add whitespace inside block delimiters

9f672ba

Merge branch 'trunk' into 64531/ensure-whitespace-check-assertEqualHTML

19ed504

sirreal added 2 commits January 20, 2026 15:32

Correct whitespace in scripts HTML tests

1e9b067

lint

76ec5b1

sirreal commented Jan 20, 2026

View reviewed changes

Cleanup debug code

79d0a66

sirreal marked this pull request as ready for review January 20, 2026 14:49

sirreal added 10 commits January 20, 2026 16:13

Fix script modules tests

e90bfbf

Remove redundant "snapshots" from assertEqualHTML test assertion mess…

e205a2c

…ages The diff in the HTML is already presented by these tests. Printing again just introduces more noise.

Fix archives tests

2493b26

Use nowdoc without indentation for block_markup

b2cca85

Remove redundant snapshot from assertion message

1bfbe89

assertEqualHTML already displays HTML differences

Fix simple test, remove extra whitespace

1580d3b

Add nested blocks text nodes test

e44a2ad

Fix whitespace in blocks tests

951307e

Debugging code with invis chars

23e18f7

Revert "Debugging code with invis chars"

d2a2977

This reverts commit 23e18f7.

remove block indentation

29faaf5

Fix block-template-utils HTML whitespace in tests

236267a

dmsnell reviewed Jan 20, 2026

View reviewed changes

sirreal added 2 commits January 21, 2026 11:30

Improve comment language

f670eb8

Merge branch 'trunk' into 64531/ensure-whitespace-check-assertEqualHTML

6e9877b

		$expected = "<script src='/main-script-d4.js' id='main-script-d4-js' data-wp-strategy='defer'></script>";
		$this->assertEqualHTMLScriptTagById( $expected, $output, 'Scripts registered as defer but that have all dependents with no strategy, should become blocking (no strategy).' );

	$block_markup = '
	<!-- wp:static -->
	<div class="static">
	<!-- wp:static-child -->
	<div class="static-child">First child</div>
	<!-- /wp:static-child -->
	<!-- wp:dynamic /-->
	<!-- wp:static-child -->
	<div class="static-child">Last child</div>
	<!-- /wp:static-child -->
	</div>
	<!-- /wp:static -->
	';

Tests: Ensure whitespace appears in assertEqualHTML tests #10765

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Tests: Ensure whitespace appears in assertEqualHTML tests #10765

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Test using WordPress Playground

Some things to be aware of

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dmsnell Jan 20, 2026

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sirreal Jan 21, 2026

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sirreal commented Jan 20, 2026 •

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github-actions bot commented Jan 20, 2026 •

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sirreal commented Jan 20, 2026 •

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