diff --git a/helix-term/tests/integration.rs b/helix-term/tests/integration.rs
index 5e418cebd..7d908cb7d 100644
--- a/helix-term/tests/integration.rs
+++ b/helix-term/tests/integration.rs
@@ -19,6 +19,7 @@ mod test {
     mod auto_pairs;
     mod command_line;
     mod commands;
+    mod comments;
     mod languages;
     mod movement;
     mod splits;
diff --git a/helix-term/tests/test/commands.rs b/helix-term/tests/test/commands.rs
index 537bc4827..398ab025e 100644
--- a/helix-term/tests/test/commands.rs
+++ b/helix-term/tests/test/commands.rs
@@ -653,411 +653,6 @@ async fn test_join_selections_space() -> anyhow::Result<()> {
     Ok(())
 }
 
-/// Comment and uncomment
-#[tokio::test(flavor = "multi_thread")]
-async fn test_injected_comment_tokens_simple() -> anyhow::Result<()> {
-    // Uncomment inner injection
-    test((
-        indoc! {r#"\
-            <p>Comment toggle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment toggle #[|on this line s]#hould use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> c",
-        indoc! {r#"\
-            <p>Comment toggle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              Comment toggle #[|on this line s]#hould use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-
-    // Comment inner injection
-    test((
-        indoc! {r#"\
-            <p>Comment toggle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              Comment toggle #[|on this line s]#hould use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> c",
-        indoc! {r#"\
-            <p>Comment toggle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment toggle #[|on this line s]#hould use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-
-    // Block comment inner injection
-    test((
-        indoc! {r#"\
-            <p>Comment toggle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment toggle #[|on this line s]#hould use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> C",
-        indoc! {r#"\
-            <p>Comment toggle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment toggle #[|/* on this line s */]#hould use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-
-    // Block uncomment inner injection
-    test((
-        indoc! {r#"\
-            <p>Comment toggle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment toggle #[|/* on this line s */]#hould use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> C",
-        indoc! {r#"\
-            <p>Comment toggle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment toggle #[|on this line s]#hould use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-
-    Ok(())
-}
-
-/// Selections in different regions
-#[tokio::test(flavor = "multi_thread")]
-async fn test_injected_comment_tokens_multiple_selections() -> anyhow::Result<()> {
-    // Comments two different injection layers with different comments
-    test((
-        indoc! {r#"\
-            <p>Comment toggle #[|on this line ]#should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              Comment toggle #(|on this line )#should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> c",
-        indoc! {r#"\
-            <!-- <p>Comment toggle #[|on this line ]#should use the HTML comment token(s).</p> -->
-            <script type="text/javascript">
-              // Comment toggle #(|on this line )#should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-
-    // Uncomments two different injection layers with different comments
-    test((
-        indoc! {r#"\
-            <!-- <p>Comment toggle #[|on this line ]#should use the HTML comment token(s).</p> -->
-            <script type="text/javascript">
-              // Comment toggle #(|on this line )#should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> c",
-        indoc! {r#"\
-            <p>Comment toggle #[|on this line ]#should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              Comment toggle #(|on this line )#should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-
-    // Works with multiple selections
-    test((
-        indoc! {r#"\
-            <p>Comment toggle #(|on this line )#should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment toggle #[|on this line ]#should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> c",
-        indoc! {r#"\
-            <!-- <p>Comment toggle #(|on this line )#should use the HTML comment token(s).</p> -->
-            <script type="text/javascript">
-              Comment toggle #[|on this line ]#should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-
-    // Works with nested injection layers: html, js then css
-    test((
-        indoc! {r#"\
-            <!-- <p>Comment toggle #(|on this line)# should use the HTML comment token(s).</p> -->
-            <script type="text/javascript">
-              // Comment toggle #(|on this line)# should use the javascript comment token(s).
-              foo();
-              css`
-                h#[tml {
-                  background-color: |]#red;
-                }
-              `
-            </script>
-        "#},
-        ":lang html<ret> c",
-        indoc! {r#"\
-            <p>Comment toggle #(|on this line)# should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              Comment toggle #(|on this line)# should use the javascript comment token(s).
-              foo();
-              css`
-                /* h#[tml { */
-                  /* background-color: |]#red; */
-                }
-              `
-            </script>
-        "#},
-    ))
-    .await?;
-
-    // Works with block comment toggle across different layers
-    test((
-        indoc! {r#"\
-            <p>Comment toggle #(|on this line)# should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment toggle #[|on this line]# should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> C",
-        indoc! {r#"\
-            <p>Comment toggle #(|<!-- on this line -->)# should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment toggle #[|/* on this line */]# should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-
-    // Many selections on the same line
-    test((
-        indoc! {r#"\
-            <p>C#[|o]#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the HTML c#(|o)#mment t#(|o)#ken(s).</p>
-            <script type="text/javascript">
-              // Comment toggle on this line should use the javascript comment token(s).
-              foo();
-              css`
-                html {
-                  background-color: red;
-                }
-              `;
-            </script>
-        "#},
-        ":lang html<ret> C",
-        indoc! {r#"\
-            <p>C#[|<!-- o -->]#mment t#(|<!-- o -->)#ggle #(|<!-- o -->)#n this line sh#(|<!-- o -->)#uld use the HTML c#(|<!-- o -->)#mment t#(|<!-- o -->)#ken(s).</p>
-            <script type="text/javascript">
-              // Comment toggle on this line should use the javascript comment token(s).
-              foo();
-              css`
-                html {
-                  background-color: red;
-                }
-              `;
-            </script>
-        "#},
-    ))
-    .await?;
-    test((
-        indoc! {r#"\
-            <p>C#[|<!-- o -->]#mment t#(|<!-- o -->)#ggle #(|<!-- o -->)#n this line sh#(|<!-- o -->)#uld use the HTML c#(|<!-- o -->)#mment t#(|<!-- o -->)#ken(s).</p>
-            <script type="text/javascript">
-              // Comment toggle on this line should use the javascript comment token(s).
-              foo();
-              css`
-                html {
-                  background-color: red;
-                }
-              `;
-            </script>
-        "#},
-        ":lang html<ret> C",
-        indoc! {r#"\
-            <p>C#[|o]#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the HTML c#(|o)#mment t#(|o)#ken(s).</p>
-            <script type="text/javascript">
-              // Comment toggle on this line should use the javascript comment token(s).
-              foo();
-              css`
-                html {
-                  background-color: red;
-                }
-              `;
-            </script>
-        "#},
-    ))
-    .await?;
-
-    // Many single-selections
-    test((
-        indoc! {r#"\
-            <p>C#[|o]#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the HTML c#(|o)#mment t#(|o)#ken(s).</p>
-            <script type="text/javascript">
-              // C#(|o)#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the javascript c#(|o)#mment t#(|o)#ken(s).
-              f#(|o)##(|o)#();
-              css`
-                html {
-                  backgr#(|o)#und-c#(|o)#l#(|o)#r: red;
-                }
-              `;
-            </script>
-        "#},
-        ":lang html<ret> C",
-        indoc! {r#"\
-            <p>C#[|<!-- o -->]#mment t#(|<!-- o -->)#ggle #(|<!-- o -->)#n this line sh#(|<!-- o -->)#uld use the HTML c#(|<!-- o -->)#mment t#(|<!-- o -->)#ken(s).</p>
-            <script type="text/javascript">
-              // C#(|/* o */)#mment t#(|/* o */)#ggle #(|/* o */)#n this line sh#(|/* o */)#uld use the javascript c#(|/* o */)#mment t#(|/* o */)#ken(s).
-              f#(|/* o */)##(|/* o */)#();
-              css`
-                html {
-                  backgr#(|/* o */)#und-c#(|/* o */)#l#(|/* o */)#r: red;
-                }
-              `;
-            </script>
-        "#},
-    ))
-    .await?;
-    test((
-        indoc! {r#"\
-            <p>C#[|<!-- o -->]#mment t#(|<!-- o -->)#ggle #(|<!-- o -->)#n this line sh#(|<!-- o -->)#uld use the HTML c#(|<!-- o -->)#mment t#(|<!-- o -->)#ken(s).</p>
-            <script type="text/javascript">
-              // C#(|/* o */)#mment t#(|/* o */)#ggle #(|/* o */)#n this line sh#(|/* o */)#uld use the javascript c#(|/* o */)#mment t#(|/* o */)#ken(s).
-              f#(|/* o */)##(|/* o */)#();
-              css`
-                html {
-                  backgr#(|/* o */)#und-c#(|/* o */)#l#(|/* o */)#r: red;
-                }
-              `;
-            </script>
-        "#},
-        ":lang html<ret> C",
-        indoc! {r#"\
-            <p>C#[|o]#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the HTML c#(|o)#mment t#(|o)#ken(s).</p>
-            <script type="text/javascript">
-              // C#(|o)#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the javascript c#(|o)#mment t#(|o)#ken(s).
-              f#(|o)##(|o)#();
-              css`
-                html {
-                  backgr#(|o)#und-c#(|o)#l#(|o)#r: red;
-                }
-              `;
-            </script>
-        "#},
-    ))
-    .await?;
-
-    Ok(())
-}
-
-/// A selection that spans across several injections takes comment tokens
-/// from the injection with the bigger scope
-#[tokio::test(flavor = "multi_thread")]
-async fn test_injected_comment_tokens_selection_across_different_layers() -> anyhow::Result<()> {
-    test((
-        indoc! {r#"\
-            <p>Comment tog#[|gle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment togg]#le on this line should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> c",
-        indoc! {r#"\
-            <!-- <p>Comment tog#[|gle on this line should use the HTML comment token(s).</p> -->
-            <!-- <script type="text/javascript"> -->
-              <!-- // Comment togg]#le on this line should use the javascript comment token(s). -->
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-    test((
-        indoc! {r#"\
-            <p>Comment tog#[|gle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment togg]#le on this line should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-        ":lang html<ret> C",
-        indoc! {r#"\
-            <p>Comment tog#[|<!-- gle on this line should use the HTML comment token(s).</p>
-            <script type="text/javascript">
-              // Comment togg -->]#le on this line should use the javascript comment token(s).
-              foo();
-            </script>
-        "#},
-    ))
-    .await?;
-
-    Ok(())
-}
-
-#[tokio::test(flavor = "multi_thread")]
-async fn test_join_selections_comment() -> anyhow::Result<()> {
-    test((
-        indoc! {"\
-            /// #[a|]#bc
-            /// def
-        "},
-        ":lang rust<ret>J",
-        indoc! {"\
-            /// #[a|]#bc def
-        "},
-    ))
-    .await?;
-
-    // Only join if the comment token matches the previous line.
-    test((
-        indoc! {"\
-            #[| // a
-            // b
-            /// c
-            /// d
-            e
-            /// f
-            // g]#
-        "},
-        ":lang rust<ret>J",
-        indoc! {"\
-            #[| // a b /// c d e f // g]#
-        "},
-    ))
-    .await?;
-
-    test((
-        "#[|\t// Join comments
-\t// with indent]#",
-        ":lang go<ret>J",
-        "#[|\t// Join comments with indent]#",
-    ))
-    .await?;
-
-    Ok(())
-}
-
 #[tokio::test(flavor = "multi_thread")]
 async fn test_read_file() -> anyhow::Result<()> {
     let mut file = tempfile::NamedTempFile::new()?;
diff --git a/helix-term/tests/test/comments.rs b/helix-term/tests/test/comments.rs
new file mode 100644
index 000000000..346c22f86
--- /dev/null
+++ b/helix-term/tests/test/comments.rs
@@ -0,0 +1,412 @@
+use helix_term::application::Application;
+
+use super::*;
+
+mod insert;
+mod movement;
+mod write;
+
+/// Comment and uncomment
+#[tokio::test(flavor = "multi_thread")]
+async fn test_injected_comment_tokens_simple() -> anyhow::Result<()> {
+    // Uncomment inner injection
+    test((
+        indoc! {r#"\
+            <p>Comment toggle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment toggle #[|on this line s]#hould use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> c",
+        indoc! {r#"\
+            <p>Comment toggle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              Comment toggle #[|on this line s]#hould use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+
+    // Comment inner injection
+    test((
+        indoc! {r#"\
+            <p>Comment toggle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              Comment toggle #[|on this line s]#hould use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> c",
+        indoc! {r#"\
+            <p>Comment toggle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment toggle #[|on this line s]#hould use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+
+    // Block comment inner injection
+    test((
+        indoc! {r#"\
+            <p>Comment toggle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment toggle #[|on this line s]#hould use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> C",
+        indoc! {r#"\
+            <p>Comment toggle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment toggle #[|/* on this line s */]#hould use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+
+    // Block uncomment inner injection
+    test((
+        indoc! {r#"\
+            <p>Comment toggle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment toggle #[|/* on this line s */]#hould use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> C",
+        indoc! {r#"\
+            <p>Comment toggle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment toggle #[|on this line s]#hould use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+
+    Ok(())
+}
+
+/// Selections in different regions
+#[tokio::test(flavor = "multi_thread")]
+async fn test_injected_comment_tokens_multiple_selections() -> anyhow::Result<()> {
+    // Comments two different injection layers with different comments
+    test((
+        indoc! {r#"\
+            <p>Comment toggle #[|on this line ]#should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              Comment toggle #(|on this line )#should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> c",
+        indoc! {r#"\
+            <!-- <p>Comment toggle #[|on this line ]#should use the HTML comment token(s).</p> -->
+            <script type="text/javascript">
+              // Comment toggle #(|on this line )#should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+
+    // Uncomments two different injection layers with different comments
+    test((
+        indoc! {r#"\
+            <!-- <p>Comment toggle #[|on this line ]#should use the HTML comment token(s).</p> -->
+            <script type="text/javascript">
+              // Comment toggle #(|on this line )#should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> c",
+        indoc! {r#"\
+            <p>Comment toggle #[|on this line ]#should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              Comment toggle #(|on this line )#should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+
+    // Works with multiple selections
+    test((
+        indoc! {r#"\
+            <p>Comment toggle #(|on this line )#should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment toggle #[|on this line ]#should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> c",
+        indoc! {r#"\
+            <!-- <p>Comment toggle #(|on this line )#should use the HTML comment token(s).</p> -->
+            <script type="text/javascript">
+              Comment toggle #[|on this line ]#should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+
+    // Works with nested injection layers: html, js then css
+    test((
+        indoc! {r#"\
+            <!-- <p>Comment toggle #(|on this line)# should use the HTML comment token(s).</p> -->
+            <script type="text/javascript">
+              // Comment toggle #(|on this line)# should use the javascript comment token(s).
+              foo();
+              css`
+                h#[tml {
+                  background-color: |]#red;
+                }
+              `
+            </script>
+        "#},
+        ":lang html<ret> c",
+        indoc! {r#"\
+            <p>Comment toggle #(|on this line)# should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              Comment toggle #(|on this line)# should use the javascript comment token(s).
+              foo();
+              css`
+                /* h#[tml { */
+                  /* background-color: |]#red; */
+                }
+              `
+            </script>
+        "#},
+    ))
+    .await?;
+
+    // Works with block comment toggle across different layers
+    test((
+        indoc! {r#"\
+            <p>Comment toggle #(|on this line)# should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment toggle #[|on this line]# should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> C",
+        indoc! {r#"\
+            <p>Comment toggle #(|<!-- on this line -->)# should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment toggle #[|/* on this line */]# should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+
+    // Many selections on the same line
+    test((
+        indoc! {r#"\
+            <p>C#[|o]#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the HTML c#(|o)#mment t#(|o)#ken(s).</p>
+            <script type="text/javascript">
+              // Comment toggle on this line should use the javascript comment token(s).
+              foo();
+              css`
+                html {
+                  background-color: red;
+                }
+              `;
+            </script>
+        "#},
+        ":lang html<ret> C",
+        indoc! {r#"\
+            <p>C#[|<!-- o -->]#mment t#(|<!-- o -->)#ggle #(|<!-- o -->)#n this line sh#(|<!-- o -->)#uld use the HTML c#(|<!-- o -->)#mment t#(|<!-- o -->)#ken(s).</p>
+            <script type="text/javascript">
+              // Comment toggle on this line should use the javascript comment token(s).
+              foo();
+              css`
+                html {
+                  background-color: red;
+                }
+              `;
+            </script>
+        "#},
+    ))
+    .await?;
+    test((
+        indoc! {r#"\
+            <p>C#[|<!-- o -->]#mment t#(|<!-- o -->)#ggle #(|<!-- o -->)#n this line sh#(|<!-- o -->)#uld use the HTML c#(|<!-- o -->)#mment t#(|<!-- o -->)#ken(s).</p>
+            <script type="text/javascript">
+              // Comment toggle on this line should use the javascript comment token(s).
+              foo();
+              css`
+                html {
+                  background-color: red;
+                }
+              `;
+            </script>
+        "#},
+        ":lang html<ret> C",
+        indoc! {r#"\
+            <p>C#[|o]#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the HTML c#(|o)#mment t#(|o)#ken(s).</p>
+            <script type="text/javascript">
+              // Comment toggle on this line should use the javascript comment token(s).
+              foo();
+              css`
+                html {
+                  background-color: red;
+                }
+              `;
+            </script>
+        "#},
+    ))
+    .await?;
+
+    // Many single-selections
+    test((
+        indoc! {r#"\
+            <p>C#[|o]#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the HTML c#(|o)#mment t#(|o)#ken(s).</p>
+            <script type="text/javascript">
+              // C#(|o)#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the javascript c#(|o)#mment t#(|o)#ken(s).
+              f#(|o)##(|o)#();
+              css`
+                html {
+                  backgr#(|o)#und-c#(|o)#l#(|o)#r: red;
+                }
+              `;
+            </script>
+        "#},
+        ":lang html<ret> C",
+        indoc! {r#"\
+            <p>C#[|<!-- o -->]#mment t#(|<!-- o -->)#ggle #(|<!-- o -->)#n this line sh#(|<!-- o -->)#uld use the HTML c#(|<!-- o -->)#mment t#(|<!-- o -->)#ken(s).</p>
+            <script type="text/javascript">
+              // C#(|/* o */)#mment t#(|/* o */)#ggle #(|/* o */)#n this line sh#(|/* o */)#uld use the javascript c#(|/* o */)#mment t#(|/* o */)#ken(s).
+              f#(|/* o */)##(|/* o */)#();
+              css`
+                html {
+                  backgr#(|/* o */)#und-c#(|/* o */)#l#(|/* o */)#r: red;
+                }
+              `;
+            </script>
+        "#},
+    ))
+    .await?;
+    test((
+        indoc! {r#"\
+            <p>C#[|<!-- o -->]#mment t#(|<!-- o -->)#ggle #(|<!-- o -->)#n this line sh#(|<!-- o -->)#uld use the HTML c#(|<!-- o -->)#mment t#(|<!-- o -->)#ken(s).</p>
+            <script type="text/javascript">
+              // C#(|/* o */)#mment t#(|/* o */)#ggle #(|/* o */)#n this line sh#(|/* o */)#uld use the javascript c#(|/* o */)#mment t#(|/* o */)#ken(s).
+              f#(|/* o */)##(|/* o */)#();
+              css`
+                html {
+                  backgr#(|/* o */)#und-c#(|/* o */)#l#(|/* o */)#r: red;
+                }
+              `;
+            </script>
+        "#},
+        ":lang html<ret> C",
+        indoc! {r#"\
+            <p>C#[|o]#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the HTML c#(|o)#mment t#(|o)#ken(s).</p>
+            <script type="text/javascript">
+              // C#(|o)#mment t#(|o)#ggle #(|o)#n this line sh#(|o)#uld use the javascript c#(|o)#mment t#(|o)#ken(s).
+              f#(|o)##(|o)#();
+              css`
+                html {
+                  backgr#(|o)#und-c#(|o)#l#(|o)#r: red;
+                }
+              `;
+            </script>
+        "#},
+    ))
+    .await?;
+
+    Ok(())
+}
+
+/// A selection that spans across several injections takes comment tokens
+/// from the injection with the bigger scope
+#[tokio::test(flavor = "multi_thread")]
+async fn test_injected_comment_tokens_selection_across_different_layers() -> anyhow::Result<()> {
+    test((
+        indoc! {r#"\
+            <p>Comment tog#[|gle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment togg]#le on this line should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> c",
+        indoc! {r#"\
+            <!-- <p>Comment tog#[|gle on this line should use the HTML comment token(s).</p> -->
+            <!-- <script type="text/javascript"> -->
+              <!-- // Comment togg]#le on this line should use the javascript comment token(s). -->
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+    test((
+        indoc! {r#"\
+            <p>Comment tog#[|gle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment togg]#le on this line should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+        ":lang html<ret> C",
+        indoc! {r#"\
+            <p>Comment tog#[|<!-- gle on this line should use the HTML comment token(s).</p>
+            <script type="text/javascript">
+              // Comment togg -->]#le on this line should use the javascript comment token(s).
+              foo();
+            </script>
+        "#},
+    ))
+    .await?;
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn test_join_selections_comment() -> anyhow::Result<()> {
+    test((
+        indoc! {"\
+            /// #[a|]#bc
+            /// def
+        "},
+        ":lang rust<ret>J",
+        indoc! {"\
+            /// #[a|]#bc def
+        "},
+    ))
+    .await?;
+
+    // Only join if the comment token matches the previous line.
+    test((
+        indoc! {"\
+            #[| // a
+            // b
+            /// c
+            /// d
+            e
+            /// f
+            // g]#
+        "},
+        ":lang rust<ret>J",
+        indoc! {"\
+            #[| // a b /// c d e f // g]#
+        "},
+    ))
+    .await?;
+
+    test((
+        "#[|\t// Join comments
+\t// with indent]#",
+        ":lang go<ret>J",
+        "#[|\t// Join comments with indent]#",
+    ))
+    .await?;
+
+    Ok(())
+}