diff --git a/tests/Elastic.Markdown.Tests/CodeBlocks/CallOutTests.cs b/tests/Elastic.Markdown.Tests/CodeBlocks/CallOutTests.cs
index cf4a70c13..0d3189d69 100644
--- a/tests/Elastic.Markdown.Tests/CodeBlocks/CallOutTests.cs
+++ b/tests/Elastic.Markdown.Tests/CodeBlocks/CallOutTests.cs
@@ -118,21 +118,23 @@ public void ParsesMagicCallOuts() => Block!.CallOuts
 
 	[Fact]
 	public void RendersExpectedHtml() =>
-		Html.ReplaceLineEndings().Should().Contain("""
-		                      <div class="highlight-csharp notranslate">
-		                      	<div class="highlight">
-		                      		<pre><code class="language-csharp">var x = 1;<span style="display: inline-block; width: 1ch"></span><span class="code-callout" data-index="1"></span>
-		                      var y = x - 2;
-		                      var z = y - 2;<span style="display: inline-block; width: 1ch"></span><span class="code-callout" data-index="2"></span>
-		                      </code></pre>
-		                      	</div>
-		                      </div>
-		                      <p><strong>OUTPUT:</strong></p>
-		                      <ol class="code-callouts">
-		                      <li>Marking the first callout</li>
-		                      <li>Marking the second callout</li>
-		                      </ol>
-		                      """.ReplaceLineEndings());
+		Html.ShouldBeHtml(
+			"""
+			<div class="highlight-csharp notranslate">
+				<div class="highlight">
+					<pre><code class="language-csharp">var x = 1;<span style="display: inline-block; width: 1ch"></span><span class="code-callout" data-index="1"></span>
+					  var y = x - 2;
+					  var z = y - 2;<span style="display: inline-block; width: 1ch"></span><span class="code-callout" data-index="2"></span>
+					</code></pre>
+			</div>
+			</div>
+			<p><strong>OUTPUT:</strong></p>
+			<ol class="code-callouts">
+			  <li>Marking the first callout</li>
+			  <li>Marking the second callout</li>
+			</ol>
+			"""
+		);
 
 
 	[Fact]
@@ -367,12 +369,14 @@ public void ParsesCallouts() => Block!.CallOuts
 
 	[Fact]
 	public void RenderedHtmlContainsCallouts() =>
-		Html.ReplaceLineEndings().Should().Contain("""
-                              <ol class="code-callouts">
-                              <li>First callout</li>
-                              <li>Second callout</li>
-                              </ol>
-                              """.ReplaceLineEndings());
+		Html.ShouldContainHtml(
+			"""
+			<ol class="code-callouts">
+			<li>First callout</li>
+			<li>Second callout</li>
+			</ol>
+			"""
+		);
 }
 
 public class CodeBlockWithMultipleCommentTypesThenList(ITestOutputHelper output) : CodeBlockCallOutTests(output, "csharp",
@@ -426,10 +430,15 @@ public void ParsesCallouts() => Block!.CallOuts
 
 	[Fact]
 	public void RendersIntermediateParagraph() =>
-		Html.ReplaceLineEndings().Should().Contain("""
-                              <p><strong>This is an intermediate paragraph</strong></p>
-                              <ol class="code-callouts">
-                              """.ReplaceLineEndings());
+		Html.ShouldContainHtml(
+			"""
+			<p><strong>This is an intermediate paragraph</strong></p>
+			<ol class="code-callouts">
+				<li>First callout</li>
+			    <li>Second callout</li>
+			</ol>
+			"""
+		);
 }
 
 public class CodeBlockWithCommentBlocksTwoParagraphsThenList(ITestOutputHelper output) : CodeBlockCallOutTests(output, "csharp",
diff --git a/tests/Elastic.Markdown.Tests/FileInclusion/IncludeTests.cs b/tests/Elastic.Markdown.Tests/FileInclusion/IncludeTests.cs
index ce0269283..7be8a1d9e 100644
--- a/tests/Elastic.Markdown.Tests/FileInclusion/IncludeTests.cs
+++ b/tests/Elastic.Markdown.Tests/FileInclusion/IncludeTests.cs
@@ -31,10 +31,7 @@ protected override void AddToFileSystem(MockFileSystem fileSystem)
 
 	[Fact]
 	public void IncludesInclusionHtml() =>
-		Html.Should()
-			.Contain("Hello world")
-			.And.Be("<p><em>Hello world</em></p>")
-		;
+		Html.ShouldBeHtml("<p><em>Hello world</em></p>");
 }
 
 
diff --git a/tests/Elastic.Markdown.Tests/Inline/AnchorLinkTests.cs b/tests/Elastic.Markdown.Tests/Inline/AnchorLinkTests.cs
index a939884df..df39ee5f8 100644
--- a/tests/Elastic.Markdown.Tests/Inline/AnchorLinkTests.cs
+++ b/tests/Elastic.Markdown.Tests/Inline/AnchorLinkTests.cs
@@ -56,8 +56,7 @@ public class InPageAnchorTests(ITestOutputHelper output) : AnchorLinkTestBase(ou
 {
 	[Fact]
 	public void GeneratesHtml() =>
-		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p><a href="#hello-world">Hello</a></p>"""
 		);
 
diff --git a/tests/Elastic.Markdown.Tests/Inline/CommentTest.cs b/tests/Elastic.Markdown.Tests/Inline/CommentTest.cs
index 3c8337aff..ebd941efc 100644
--- a/tests/Elastic.Markdown.Tests/Inline/CommentTest.cs
+++ b/tests/Elastic.Markdown.Tests/Inline/CommentTest.cs
@@ -14,18 +14,21 @@ not a comment
 {
 
 	[Fact]
-	public void GeneratesAttributesInHtml() =>
+	public void GeneratesAttributesInHtml()
+	{
 		// language=html
 		Html.Should().NotContain(
-			"""<p>% comment"""
-		)
-		.And.Contain(
-			"""<p>not a comment</p>"""
-		).And.Be(
+				"""<p>% comment"""
+			)
+			.And.Contain(
+				"""<p>not a comment</p>"""
+			);
+		Html.ShouldBeHtml(
 			"""
 			<p>not a comment</p>
 			"""
 		);
+	}
 }
 
 public class MultipleLineCommentTest(ITestOutputHelper output) : InlineTest(output,
@@ -43,23 +46,27 @@ also not a comment
 {
 
 	[Fact]
-	public void GeneratesAttributesInHtml() =>
+	public void GeneratesAttributesInHtml()
+	{
 		// language=html
-		Html.ReplaceLineEndings().Should().NotContainAny(
+		Html.Should().NotContainAny(
 				"<p><!--",
 				"<p>Multi line comment, first line",
 				"<p>Another line inside the commented area",
 				"<p>end of comments",
-				"<p>-->")
+				"<p>-->"
+			)
 			.And.ContainAll(
 				"<p>not a comment, and multi line comment below</p>",
 				"<p>also not a comment</p>"
-			).And.Be(
-				"""
-				<p>not a comment, and multi line comment below</p>
-				<p>also not a comment</p>
-				""".ReplaceLineEndings()
-				);
+			);
+		Html.ShouldBeHtml(
+			"""
+			<p>not a comment, and multi line comment below</p>
+			<p>also not a comment</p>
+			"""
+		);
+	}
 }
 
 public class MultipleLineCommentWithLinkTest(ITestOutputHelper output) : InlineTest(output,
@@ -80,7 +87,8 @@ also not a comment
 	public void HasNoErrors() => Collector.Diagnostics.Should().HaveCount(0);
 
 	[Fact]
-	public void GeneratesAttributesInHtml() =>
+	public void GeneratesAttributesInHtml()
+	{
 		// language=html
 		Html.ReplaceLineEndings().Should().NotContainAny(
 				"<p><!--",
@@ -92,10 +100,12 @@ public void GeneratesAttributesInHtml() =>
 			.And.ContainAll(
 				"<p>not a comment, and multi line comment below</p>",
 				"<p>also not a comment</p>"
-			).And.Be(
-				"""
-					<p>not a comment, and multi line comment below</p>
-					<p>also not a comment</p>
-					""".ReplaceLineEndings()
 			);
+		Html.ShouldBeHtml(
+			"""
+			<p>not a comment, and multi line comment below</p>
+			<p>also not a comment</p>
+			"""
+		);
+	}
 }
diff --git a/tests/Elastic.Markdown.Tests/Inline/DirectiveBlockLinkTests.cs b/tests/Elastic.Markdown.Tests/Inline/DirectiveBlockLinkTests.cs
index f87c0df2a..29905ffb3 100644
--- a/tests/Elastic.Markdown.Tests/Inline/DirectiveBlockLinkTests.cs
+++ b/tests/Elastic.Markdown.Tests/Inline/DirectiveBlockLinkTests.cs
@@ -48,7 +48,7 @@ public class InPageDirectiveLinkTests(ITestOutputHelper output) : DirectiveBlock
 	[Fact]
 	public void GeneratesHtml() =>
 		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p><a href="#caution_ref">Hello</a></p>"""
 		);
 
diff --git a/tests/Elastic.Markdown.Tests/Inline/HardBreakTests.cs b/tests/Elastic.Markdown.Tests/Inline/HardBreakTests.cs
index 09926a143..378eb84ab 100644
--- a/tests/Elastic.Markdown.Tests/Inline/HardBreakTests.cs
+++ b/tests/Elastic.Markdown.Tests/Inline/HardBreakTests.cs
@@ -12,7 +12,7 @@ public class AllowBrTagTest(ITestOutputHelper output)
 {
 	[Fact]
 	public void GeneratesHtml() =>
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"<p>Hello,<br>World!</p>"
 		);
 }
@@ -23,7 +23,7 @@ public class BrTagNeedsToBeExact(ITestOutputHelper output)
 {
 	[Fact]
 	public void GeneratesHtml() =>
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"<p>Hello,&lt;br &gt;World&lt;br /&gt;!</p>"
 		);
 }
@@ -35,7 +35,7 @@ public class DisallowSpanTag(ITestOutputHelper output)
 	[Fact]
 	// span tag is rendered as text
 	public void GeneratesHtml() =>
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"<p>Hello,&lt;span&gt;World!&lt;/span&gt;</p>"
 		);
 }
diff --git a/tests/Elastic.Markdown.Tests/Inline/InlineAnchorTests.cs b/tests/Elastic.Markdown.Tests/Inline/InlineAnchorTests.cs
index 41e92e74d..317ee5c7a 100644
--- a/tests/Elastic.Markdown.Tests/Inline/InlineAnchorTests.cs
+++ b/tests/Elastic.Markdown.Tests/Inline/InlineAnchorTests.cs
@@ -26,8 +26,7 @@ public void ParsesBlock()
 
 	[Fact]
 	public void GeneratesAttributesInHtml() =>
-		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p>this is regular text and this <a id="is-an-inline-anchor"></a> and this continues to be regular text</p>"""
 		);
 }
@@ -69,7 +68,7 @@ public void ParsesBlock()
 	[Fact]
 	public void GeneratesAttributesInHtml() =>
 		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p>this is regular text and this <a id="is-an-inline-anchor"></a></p>"""
 		);
 }
@@ -97,7 +96,7 @@ this is regular text and this $$$is-an-inline-anchor$$
 	[Fact]
 	public void GeneratesAttributesInHtml() =>
 		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p>this is regular text and this $$$is-an-inline-anchor$$</p>"""
 		);
 }
@@ -111,11 +110,11 @@ public class InlineAnchorInHeading(ITestOutputHelper output) : BlockTest<Heading
 	[Fact]
 	public void GeneratesAttributesInHtml() =>
 		// language=html
-		Html.ReplaceLineEndings().TrimEnd().Should().Be(
+		Html.ShouldBeHtml(
 			"""
 			<div class="heading-wrapper" id="hello-world"><h2><a class="headerlink" href="#hello-world">Hello world <a id="my-anchor"></a></a></h2>
 			</div>
-			""".ReplaceLineEndings().TrimEnd()
+			"""
 		);
 }
 
@@ -128,11 +127,12 @@ public class ExplicitSlugInHeader(ITestOutputHelper output) : BlockTest<HeadingB
 	[Fact]
 	public void GeneratesAttributesInHtml() =>
 		// language=html
-		Html.ReplaceLineEndings().TrimEnd().Should().Be(
+		Html.ShouldBeHtml(
 			"""
-			<div class="heading-wrapper" id="my-anchor"><h2><a class="headerlink" href="#my-anchor">Hello world</a></h2>
+			<div class="heading-wrapper" id="my-anchor">
+				<h2><a class="headerlink" href="#my-anchor">Hello world</a></h2>
 			</div>
-			""".ReplaceLineEndings().TrimEnd()
+			"""
 		);
 }
 
@@ -182,7 +182,7 @@ public class InlineAnchorCanBeLinkedToo(ITestOutputHelper output) : InlineAnchor
 	[Fact]
 	public void GeneratesHtml() =>
 		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p><a href="#same-page-anchor">Hello</a></p>"""
 		);
 
diff --git a/tests/Elastic.Markdown.Tests/Inline/InlineImageTest.cs b/tests/Elastic.Markdown.Tests/Inline/InlineImageTest.cs
index b66c370ce..40af3f948 100644
--- a/tests/Elastic.Markdown.Tests/Inline/InlineImageTest.cs
+++ b/tests/Elastic.Markdown.Tests/Inline/InlineImageTest.cs
@@ -18,7 +18,7 @@ public class InlineImageTest(ITestOutputHelper output) : InlineTest<LinkInline>(
 	[Fact]
 	public void GeneratesAttributesInHtml() =>
 		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p><img src="/docs/_static/img/observability.png" alt="Elasticsearch" /></p>"""
 		);
 }
@@ -35,7 +35,7 @@ public class RelativeInlineImageTest(ITestOutputHelper output) : InlineTest<Link
 	[Fact]
 	public void GeneratesAttributesInHtml() =>
 		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p><img src="/docs/_static/img/observability.png" alt="Elasticsearch" /></p>"""
 		);
 }
diff --git a/tests/Elastic.Markdown.Tests/Inline/InlineLinkTests.cs b/tests/Elastic.Markdown.Tests/Inline/InlineLinkTests.cs
index f05df1411..c4049422c 100644
--- a/tests/Elastic.Markdown.Tests/Inline/InlineLinkTests.cs
+++ b/tests/Elastic.Markdown.Tests/Inline/InlineLinkTests.cs
@@ -124,8 +124,7 @@ public class CrossLinkReferenceTest(ITestOutputHelper output) : LinkTestBase(out
 {
 	[Fact]
 	public void GeneratesHtml() =>
-		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p><a href="https://docs-v3-preview.elastic.dev/elastic/kibana/tree/main/">test</a></p>"""
 		);
 
@@ -188,8 +187,7 @@ [link to app]({{some-url-with-a-version}})
 {
 	[Fact]
 	public void GeneratesHtml() =>
-		// language=html
-		Html.Should().Contain(
+		Html.ShouldContainHtml(
 			"""<p><a href="https://github.com/elastic/fake-repo/tree/v1.17.0" target="_blank" rel="noopener noreferrer">link to app</a></p>"""
 		);
 
@@ -262,7 +260,7 @@ public class CommentedNonExistingLinks2(ITestOutputHelper output) : LinkTestBase
 {
 	[Fact]
 	public void GeneratesHtml() =>
-		Html.ShouldMatchHtml(
+		Html.ShouldBeHtml(
 			"""
 			<p>Links:</p>
 			<ul>
diff --git a/tests/Elastic.Markdown.Tests/Inline/SubstitutionTest.cs b/tests/Elastic.Markdown.Tests/Inline/SubstitutionTest.cs
index fdc43ac77..26af37945 100644
--- a/tests/Elastic.Markdown.Tests/Inline/SubstitutionTest.cs
+++ b/tests/Elastic.Markdown.Tests/Inline/SubstitutionTest.cs
@@ -159,7 +159,7 @@ public class ReplaceInHeader(ITestOutputHelper output) : InlineTest(output,
 
 	[Fact]
 	public void OnlySeesGlobalVariable() =>
-		Html.Should().Contain("<h2><a class=\"headerlink\" href=\"#custom-anchor\">Hello World!</a></h2>");
+		Html.ShouldContainHtml("""<h2><a class="headerlink" href="#custom-anchor">Hello World!</a></h2>""");
 
 	[Fact]
 	public void HasNoErrors() => Collector.Diagnostics.Should().HaveCount(0);
diff --git a/tests/Elastic.Markdown.Tests/PrettyHtmlExtensions.cs b/tests/Elastic.Markdown.Tests/PrettyHtmlExtensions.cs
index 08a7279d5..54084da35 100644
--- a/tests/Elastic.Markdown.Tests/PrettyHtmlExtensions.cs
+++ b/tests/Elastic.Markdown.Tests/PrettyHtmlExtensions.cs
@@ -50,7 +50,7 @@ public static string PrettyHtml([LanguageInjection("html")] this string html, bo
 		return sw.ToString().TrimStart('\n');
 	}
 
-	public static void ShouldMatchHtml(
+	public static void ShouldBeHtml(
 		[LanguageInjection("html")] this string actual,
 		[LanguageInjection("html")] string expected,
 		bool sanitize = true
@@ -79,7 +79,13 @@ public static void ShouldContainHtml(
 		expected = expected.Trim('\n').PrettyHtml(sanitize);
 		actual = actual.Trim('\n').PrettyHtml(sanitize);
 
-		actual.Should().Contain(expected);
+		var actualCompare = actual.Replace("\t", string.Empty);
+		var expectedCompare = actual.Replace("\t", string.Empty);
+
+		// we compare over unindented HTML, but if that fails, we rely on the pretty HTML Contain().
+		// to throw for improved error messages
+		if (!actualCompare.Contains(expectedCompare))
+			actual.Should().Contain(expected);
 	}
 
 	public static string CreateDiff(this string actual, string expected, bool sanitize = true)