diff --git a/Cargo.lock b/Cargo.lock
index e43ab0d95d9..c5a39eb221a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,7 +2,7 @@
 name = "rustfmt"
 version = "0.2.1"
 dependencies = [
- "diff 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "diff 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -30,7 +30,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "diff"
-version = "0.1.7"
+version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index 17bd20a0561..78b359de177 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,7 +20,7 @@ unicode-segmentation = "0.1.2"
 regex = "0.1.41"
 term = "0.2.11"
 strings = "0.0.1"
-diff = "0.1.7"
+diff = "0.1.8"
 syntex_syntax = "0.23.0"
 log = "0.3.2"
 env_logger = "0.3.1"
diff --git a/src/rustfmt_diff.rs b/src/rustfmt_diff.rs
index 8c20b8f5a0f..4bb858a6b30 100644
--- a/src/rustfmt_diff.rs
+++ b/src/rustfmt_diff.rs
@@ -2,12 +2,14 @@ use std::collections::VecDeque;
 use diff;
 use term;
 
+#[derive(Debug, PartialEq)]
 pub enum DiffLine {
     Context(String),
     Expected(String),
     Resulting(String),
 }
 
+#[derive(Debug, PartialEq)]
 pub struct Mismatch {
     pub line_number: u32,
     pub lines: Vec<DiffLine>,
diff --git a/tests/system.rs b/tests/system.rs
index 6d3c817256c..d6f1ba806f5 100644
--- a/tests/system.rs
+++ b/tests/system.rs
@@ -273,3 +273,17 @@ fn get_target(file_name: &str, target: Option<&str>, write_mode: WriteMode) -> S
         file_name.to_owned()
     }
 }
+
+#[test]
+fn rustfmt_diff_make_diff_tests() {
+    let diff = make_diff("a\nb\nc\nd", "a\ne\nc\nd", 3);
+    assert_eq!(diff,
+               vec![Mismatch {
+                        line_number: 1,
+                        lines: vec![DiffLine::Context("a".into()),
+                                    DiffLine::Resulting("b".into()),
+                                    DiffLine::Expected("e".into()),
+                                    DiffLine::Context("c".into()),
+                                    DiffLine::Context("d".into())],
+                    }]);
+}