diff --git a/packages/mdbook-rust/tests/integration.rs b/packages/mdbook-rust/tests/integration.rs
index b5381f4..03e2705 100644
--- a/packages/mdbook-rust/tests/integration.rs
+++ b/packages/mdbook-rust/tests/integration.rs
@@ -5,6 +5,20 @@ fn check(source: &str, expected: &str) {
     assert_eq!(write_module(source).unwrap(), Some(expected.to_string()));
 }
 
+#[test]
+fn empty() {
+    assert!(write_module("").unwrap().is_none());
+}
+
+#[test]
+fn ignored() {
+    assert!(write_module(indoc! {"
+        fn ingnore_me() {}
+    "})
+    .unwrap()
+    .is_none());
+}
+
 #[test]
 fn basic() {
     check(
@@ -27,3 +41,98 @@ fn basic() {
         "},
     )
 }
+
+#[test]
+fn empty_body() {
+    check("fn body() {}", "\n")
+}
+
+#[test]
+fn line_comment_indent() {
+    check(
+        indoc! {"
+            fn body() {
+                //# No space after comment marker
+                //
+                // - Item 1
+                //- Item 2 with no space after comment marker
+                //   - Sub-item
+            }
+        "},
+        indoc! {"
+            # No space after comment marker
+            
+            - Item 1
+            - Item 2 with no space after comment marker
+              - Sub-item
+        "},
+    )
+}
+
+#[test]
+fn block_comment_indent() {
+    check(
+        indoc! {"
+            fn body() {
+                /*
+                # Heading
+                
+                - Item 1
+                - Item 2
+                  - Sub-item
+                */
+            }
+        "},
+        indoc! {"
+
+            # Heading
+            
+            - Item 1
+            - Item 2
+              - Sub-item
+
+        "},
+    )
+}
+
+#[test]
+fn code_only() {
+    check(
+        indoc! {"
+            fn body() {
+                let x = 1;
+                let y = 1;
+            }
+        "},
+        indoc! {"
+
+
+            ```rust
+            let x = 1;
+            let y = 1;
+            ```
+        "},
+    )
+}
+
+#[test]
+fn code_spacing() {
+    check(
+        indoc! {"
+            fn body() {
+                let x = 1;
+
+                let y = 1;
+            }
+        "},
+        indoc! {"
+
+
+            ```rust
+            let x = 1;
+
+            let y = 1;
+            ```
+        "},
+    )
+}