diff --git a/Cargo.lock b/Cargo.lock
index ab5be762..6785f076 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -966,7 +966,6 @@ version = "0.25.0"
 dependencies = [
  "codespan",
  "codespan-reporting",
- "diff",
  "full_moon",
  "id-arena",
  "if_chain",
@@ -979,6 +978,7 @@ dependencies = [
  "serde",
  "serde_json",
  "serde_yaml",
+ "similar",
  "termcolor",
  "toml",
 ]
@@ -1051,6 +1051,12 @@ dependencies = [
  "lazy_static",
 ]
 
+[[package]]
+name = "similar"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2aeaf503862c419d66959f5d7ca015337d864e9c49485d771b732e2a20453597"
+
 [[package]]
 name = "smallvec"
 version = "1.10.0"
diff --git a/Cargo.toml b/Cargo.toml
index df846898..97581cf8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,18 +1,18 @@
-[workspace]
-
-members = ["selene", "selene-lib"]
-
-[workspace.package]
-version = "0.25.0"
-authors = ["Kampfkarren <kampfkarren@gmail.com>"]
-edition = "2021"
-homepage = "https://kampfkarren.github.io/selene/"
-license = "MPL-2.0"
-repository = "https://github.com/Kampfkarren/selene"
-
-[workspace.dependencies]
-full_moon = "0.18.0"
-toml = "0.7.2"
-
-# Do not update this without confirming profiling uses the same version of tracy-client as selene
-profiling = "1.0.7"
\ No newline at end of file
+[workspace]
+
+members = ["selene", "selene-lib"]
+
+[workspace.package]
+version = "0.25.0"
+authors = ["Kampfkarren <kampfkarren@gmail.com>"]
+edition = "2021"
+homepage = "https://kampfkarren.github.io/selene/"
+license = "MPL-2.0"
+repository = "https://github.com/Kampfkarren/selene"
+
+[workspace.dependencies]
+full_moon = "0.18.0"
+toml = "0.7.2"
+
+# Do not update this without confirming profiling uses the same version of tracy-client as selene
+profiling = "1.0.7"
diff --git a/selene-lib/Cargo.toml b/selene-lib/Cargo.toml
index 44c58138..9811f638 100644
--- a/selene-lib/Cargo.toml
+++ b/selene-lib/Cargo.toml
@@ -12,7 +12,6 @@ edition.workspace = true
 [dependencies]
 codespan = "0.11"
 codespan-reporting = "0.11"
-diff = "0.1.13"
 full_moon.workspace = true
 id-arena = "2.2"
 if_chain = "1.0.2"
@@ -23,6 +22,7 @@ profiling.workspace = true
 regex = "1.7.1"
 serde = "1.0.152"
 serde_yaml = "0.9.16"
+similar = "2.3.0"
 toml.workspace = true
 
 [dev-dependencies]
diff --git a/selene-lib/src/lints/test_util.rs b/selene-lib/src/lints/test_util.rs
index acab0a8d..e55bdd8b 100644
--- a/selene-lib/src/lints/test_util.rs
+++ b/selene-lib/src/lints/test_util.rs
@@ -3,6 +3,7 @@ use crate::{
     test_util::{get_standard_library, PrettyString},
     StandardLibrary,
 };
+use similar::{ChangeTag, TextDiff};
 use std::{
     fs,
     io::Write,
@@ -75,12 +76,13 @@ fn apply_diagnostics_fixes(code: &str, diagnostics: &Vec<Diagnostic>) -> String
 fn generate_diff(source1: &str, source2: &str) -> String {
     let mut result = String::new();
 
-    for line in diff::lines(source1, source2) {
-        match line {
-            diff::Result::Left(l) => result.push_str(&format!("-{}\n", l)),
-            diff::Result::Both(l, _) => result.push_str(&format!(" {}\n", l)),
-            diff::Result::Right(r) => result.push_str(&format!("+{}\n", r)),
-        }
+    for change in TextDiff::from_lines(source1, source2).iter_all_changes() {
+        let sign = match change.tag() {
+            ChangeTag::Delete => "-",
+            ChangeTag::Insert => "+",
+            ChangeTag::Equal => " ",
+        };
+        result.push_str(&format!("{}{}", sign, change.value()));
     }
 
     result
@@ -132,11 +134,17 @@ pub fn test_lint_config_with_output<
     let mut output = termcolor::NoColor::new(Vec::new());
 
     let fixed_lua_code = apply_diagnostics_fixes(&lua_source, &diagnostics);
-    if let Err(e) = fs::write(
-        &path_base.with_file_name(format!("{}.fixed.diff", test_name)),
-        generate_diff(lua_source.as_str(), fixed_lua_code.as_str()),
-    ) {
-        eprintln!("Failed to write to file: {}", e);
+    let fixed_diff = generate_diff(&lua_source, &fixed_lua_code);
+    let diff_output_path = path_base.with_extension("fixed.diff");
+
+    if let Ok(expected) = fs::read_to_string(&diff_output_path) {
+        pretty_assertions::assert_eq!(PrettyString(&expected), PrettyString(&fixed_diff));
+    } else {
+        let mut output_file =
+            fs::File::create(diff_output_path).expect("couldn't create fixed.diff output file");
+        output_file
+            .write_all(fixed_diff.as_bytes())
+            .expect("couldn't write fixed.diff to output file");
     }
 
     for diagnostic in diagnostics
diff --git a/selene-lib/tests/lints/empty_loop/empty_loop.fixed.diff b/selene-lib/tests/lints/empty_loop/empty_loop.fixed.diff
index f190ae84..0edc5d4a 100644
--- a/selene-lib/tests/lints/empty_loop/empty_loop.fixed.diff
+++ b/selene-lib/tests/lints/empty_loop/empty_loop.fixed.diff
@@ -71,4 +71,3 @@
 -until true
 +
  -- comment here shouldn't break anything
- 
diff --git a/selene-lib/tests/lints/empty_loop/empty_loop_comments.fixed.diff b/selene-lib/tests/lints/empty_loop/empty_loop_comments.fixed.diff
index 6ddbff5b..498d8198 100644
--- a/selene-lib/tests/lints/empty_loop/empty_loop_comments.fixed.diff
+++ b/selene-lib/tests/lints/empty_loop/empty_loop_comments.fixed.diff
@@ -17,11 +17,11 @@
  end
  
 -for _ = 1, 10 do
- 
- 
 -
--end
 -
+ 
+-end
+ 
  for _ in pairs({}) do
      return "Should not warn"
  end
@@ -70,4 +70,3 @@
 -until true
 +
  -- comment here shouldn't break anything
-