diff --git a/tests/AnnotationsTest.php b/tests/AnnotationsTest.php
index 953b15b..1b6d659 100644
--- a/tests/AnnotationsTest.php
+++ b/tests/AnnotationsTest.php
@@ -12,11 +12,11 @@ final class AnnotationsTest extends TestCase {
 ##### This is an H5 {.withAClass}
 		";
 		$target = "
-		<h1>This is an H1</h1>
-		<h2>This is an H2</h2>
-		<h3>This is an H3</h3>
-		<h4>This is an H4</h4>
-		<h5>This is an H5</h5>
+		<h1 id=\"this_is_an_h1\">This is an H1</h1>
+		<h2 id=\"this_is_an_h2\">This is an H2</h2>
+		<h3 id=\"this_is_an_h3\">This is an H3</h3>
+		<h4 id=\"this_is_an_h4\">This is an H4</h4>
+		<h5 id=\"this_is_an_h5\">This is an H5</h5>
 		";
 
 		[$source, $result] = createTest($source, $target);
diff --git a/tests/HeadingsTest.php b/tests/HeadingsTest.php
index 3091295..b750db6 100644
--- a/tests/HeadingsTest.php
+++ b/tests/HeadingsTest.php
@@ -8,7 +8,7 @@ final class HeadingsTest extends TestCase {
 # This is an H1
 		";
 		$target = "
-		<h1>This is an H1</h1>
+		<h1 id=\"this_is_an_h1\">This is an H1</h1>
 		";
 
 		[$source, $result] = createTest($source, $target);
@@ -20,7 +20,7 @@ final class HeadingsTest extends TestCase {
 ## This is an H2
 		";
 		$target = "
-		<h2>This is an H2</h2>
+		<h2 id=\"this_is_an_h2\">This is an H2</h2>
 		";
 
 		[$source, $result] = createTest($source, $target);
@@ -32,7 +32,7 @@ final class HeadingsTest extends TestCase {
 ### This is an H3
 		";
 		$target = "
-		<h3>This is an H3</h3>
+		<h3 id=\"this_is_an_h3\">This is an H3</h3>
 		";
 
 		[$source, $result] = createTest($source, $target);
@@ -44,7 +44,7 @@ final class HeadingsTest extends TestCase {
 #### This is an H4
 		";
 		$target = "
-		<h4>This is an H4</h4>
+		<h4 id=\"this_is_an_h4\">This is an H4</h4>
 		";
 
 		[$source, $result] = createTest($source, $target);
@@ -56,7 +56,7 @@ final class HeadingsTest extends TestCase {
 ##### This is an H5
 		";
 		$target = "
-		<h5>This is an H5</h5>
+		<h5 id=\"this_is_an_h5\">This is an H5</h5>
 		";
 
 		[$source, $result] = createTest($source, $target);