From bfe4f0c012d365facbb957a1e0cc379d22aac519 Mon Sep 17 00:00:00 2001
From: David Crespo <crespo.dm@gmail.com>
Date: Fri, 18 Mar 2022 16:23:01 -0500
Subject: [PATCH 1/2] pretty print unified diff with 5 line before/after window

---
 Cargo.toml          |  2 +-
 src/lib.rs          |  8 ++++----
 tests/data_a.txt    | 20 ++++++++++++++++++++
 tests/data_a2.txt   | 24 ++++++++++++++++++++++++
 tests/test_basic.rs |  7 +++++++
 5 files changed, 56 insertions(+), 5 deletions(-)
 create mode 100644 tests/data_a2.txt

diff --git a/Cargo.toml b/Cargo.toml
index 925d0f5..e6e9df6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,5 +11,5 @@ keywords = ["test", "fixture"]
 categories = ["development-tools::testing"]
 
 [dependencies]
-difference = "2.0.0"
+similar = "2.1.0"
 newline-converter = "0.2.0"
diff --git a/src/lib.rs b/src/lib.rs
index 44988ba..c36c839 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -33,8 +33,8 @@
 //! -Ten points for Gaston
 //! ```
 
-use difference::Changeset;
 use newline_converter::dos2unix;
+use similar::{udiff::unified_diff, Algorithm};
 use std::{env, fs, path::Path};
 
 /// Compare the contents of the file to the string provided
@@ -69,9 +69,9 @@ pub fn assert_contents<P: AsRef<Path>>(path: P, actual: &str) {
         let expected = dos2unix(&expected_s);
 
         if expected != actual {
-            let changeset =
-                Changeset::new(expected.as_ref(), actual.as_ref(), "\n");
-            println!("{}", changeset);
+            let diff =
+                unified_diff(Algorithm::Myers, &expected, &actual, 5, None);
+            println!("{}", diff);
             panic!(
                 r#"assertion failed: string doesn't match the contents of file: "{}" see diffset above
                 set EXPECTORATE=overwrite if these changes are intentional"#,
diff --git a/tests/data_a.txt b/tests/data_a.txt
index fee1414..8da136d 100644
--- a/tests/data_a.txt
+++ b/tests/data_a.txt
@@ -2,3 +2,23 @@ A eh?
 a a A
 a aye
 eh.
+
+A eh?
+a a A
+a aye
+eh.
+
+A eh?
+a a A
+a aye
+eh.
+
+A eh?
+a a A
+a aye
+eh.
+
+A eh?
+a a A
+a aye
+eh.
\ No newline at end of file
diff --git a/tests/data_a2.txt b/tests/data_a2.txt
new file mode 100644
index 0000000..a89c772
--- /dev/null
+++ b/tests/data_a2.txt
@@ -0,0 +1,24 @@
+A eh?
+a a A
+a aye
+eh.
+
+A eh?
+a a A
+a aye
+eh.
+
+A eh?
+a a A
+a aye
+eh.
+
+A eh?
+this line changed
+a aye
+eh.
+
+A eh?
+a a A
+a aye
+eh.
\ No newline at end of file
diff --git a/tests/test_basic.rs b/tests/test_basic.rs
index 62b1c93..23b6c56 100644
--- a/tests/test_basic.rs
+++ b/tests/test_basic.rs
@@ -14,3 +14,10 @@ fn bad() {
     let actual = include_str!("data_a.txt");
     assert_contents("tests/data_b.txt", actual);
 }
+
+#[test]
+#[should_panic]
+fn one_line_change() {
+    let actual = include_str!("data_a.txt");
+    assert_contents("tests/data_a2.txt", actual);
+}

From d62d3eef0139202dd0de3daedcd494059e094df8 Mon Sep 17 00:00:00 2001
From: David Crespo <crespo.dm@gmail.com>
Date: Mon, 21 Mar 2022 14:38:59 -0500
Subject: [PATCH 2/2] turn github commment into code comment

---
 src/lib.rs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index c36c839..51449e9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -69,8 +69,13 @@ pub fn assert_contents<P: AsRef<Path>>(path: P, actual: &str) {
         let expected = dos2unix(&expected_s);
 
         if expected != actual {
-            let diff =
-                unified_diff(Algorithm::Myers, &expected, &actual, 5, None);
+            let diff = unified_diff(
+                Algorithm::Myers, // default algorithm used by git
+                &expected,
+                &actual,
+                5, // lines before and after
+                None,
+            );
             println!("{}", diff);
             panic!(
                 r#"assertion failed: string doesn't match the contents of file: "{}" see diffset above