diff --git a/Makefile b/Makefile
index 724f9cd..b20be8c 100644
--- a/Makefile
+++ b/Makefile
@@ -24,12 +24,16 @@ clean:
 
 .PHONY: test
 test:
-> cargo test --lib
+> cargo test --lib --test test_loader
 
 .PHONY: integrationtest
 integrationtest:
 > cargo test --no-fail-fast --test test_loader
 
+.PHONY: unittest
+unittest:
+> cargo test --lib
+
 .PHONY: run
 run:
 > cargo run
diff --git a/src/compare/diff.rs b/src/compare/diff.rs
index 99287dc..186898e 100644
--- a/src/compare/diff.rs
+++ b/src/compare/diff.rs
@@ -1,4 +1,5 @@
 use super::sexp::Token;
+use super::util::assert_bounds;
 use super::util::assert_name;
 use crate::compare::util::get_offsets;
 use crate::parser::Comment;
@@ -125,21 +126,7 @@ fn compare_section<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
@@ -165,21 +152,7 @@ fn compare_heading<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
@@ -228,21 +201,7 @@ fn compare_paragraph<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
@@ -266,21 +225,7 @@ fn compare_plain_list<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
@@ -306,21 +251,7 @@ fn compare_plain_list_item<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
@@ -353,21 +284,7 @@ fn compare_greater_block<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
@@ -393,21 +310,7 @@ fn compare_dynamic_block<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
@@ -433,21 +336,7 @@ fn compare_footnote_definition<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
@@ -473,21 +362,7 @@ fn compare_comment<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
@@ -509,21 +384,7 @@ fn compare_drawer<'s>(
     let mut child_status = Vec::new();
     let mut this_status = DiffStatus::Good;
 
-    let attributes_child = children
-        .iter()
-        .nth(1)
-        .ok_or("Should have an attributes child.")?;
-    let attributes_map = attributes_child.as_map()?;
-    let begin = attributes_map
-        .get(":begin")
-        .ok_or("Missing :begin attribute.")?
-        .as_atom()?;
-    let end = attributes_map
-        .get(":end")
-        .ok_or("Missing :end attribute.")?
-        .as_atom()?;
-    let (rust_begin, rust_end) = get_offsets(source, rust);
-    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+    if assert_bounds(source, emacs, rust).is_err() {
         this_status = DiffStatus::Bad;
     }
 
diff --git a/src/compare/util.rs b/src/compare/util.rs
index 2b665e5..830556a 100644
--- a/src/compare/util.rs
+++ b/src/compare/util.rs
@@ -37,3 +37,30 @@ pub fn assert_name<'s>(emacs: &'s Token<'s>, name: &str) -> Result<(), Box<dyn s
     }
     Ok(())
 }
+
+pub fn assert_bounds<'s, S: Source<'s>>(
+    source: &'s str,
+    emacs: &'s Token<'s>,
+    rust: &'s S,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let children = emacs.as_list()?;
+    let attributes_child = children
+        .iter()
+        .nth(1)
+        .ok_or("Should have an attributes child.")?;
+    let attributes_map = attributes_child.as_map()?;
+    let begin = attributes_map
+        .get(":begin")
+        .ok_or("Missing :begin attribute.")?
+        .as_atom()?;
+    let end = attributes_map
+        .get(":end")
+        .ok_or("Missing :end attribute.")?
+        .as_atom()?;
+    let (rust_begin, rust_end) = get_offsets(source, rust);
+    if (rust_begin + 1).to_string() != begin || (rust_end + 1).to_string() != end {
+        Err(format!("Rust bounds ({rust_begin}, {rust_end}) do not match emacs bounds ({emacs_begin}, {emacs_end})", rust_begin = rust_begin + 1, rust_end = rust_end + 1, emacs_begin=begin, emacs_end=end))?;
+    }
+
+    Ok(())
+}