Only print errors on failure.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "goldenfile"
-version = "1.5.2"
+version = "1.6.0"
 edition = "2021"
 description = "Simple goldenfile testing library"
 keywords = ["goldenfile", "test", "library"]
@@ -16,5 +16,7 @@ exclude = [
 ]
 
 [dependencies]
+scopeguard = "1.2"
 similar-asserts = "1.4"
 tempfile = "3"
+yansi = "1.0.0-rc.1"

src/lib.rs

@@ -25,6 +25,9 @@
 
 #![deny(missing_docs)]
 
+#[macro_use(defer_on_unwind)]
+extern crate scopeguard;
+
 pub mod differs;
 pub mod mint;
 

src/mint.rs

@@ -8,6 +8,7 @@ use std::path::{Path, PathBuf};
 use std::thread;
 
 use tempfile::TempDir;
+use yansi::Paint;
 
 use crate::differs::*;
 
@@ -94,13 +95,15 @@ impl Mint {
         for &(ref file, ref differ) in &self.files {
             let old = self.path.join(&file);
             let new = self.tempdir.path().join(&file);
-
-            println!("\nGoldenfile diff for {:?}:", file.to_str().unwrap());
-            println!("To regenerate the goldenfile, run");
-            println!("    UPDATE_GOLDENFILES=1 cargo test");
-            println!("------------------------------------------------------------");
+            defer_on_unwind! {
+                eprintln!("note: run with `UPDATE_GOLDENFILES=1` to update goldenfiles");
+                eprintln!(
+                    "{}: goldenfile changed: {}",
+                    "error".bold().red(),
+                    file.to_str().unwrap()
+                );
+            }
             differ(&old, &new);
-            println!("<NO DIFFERENCE>");
         }
     }
 

tests/goldenfiles/match1.txt

@@ -1 +1 @@
-Hello world!
+Hello world!

tests/goldenfiles/match2.txt

@@ -1 +1 @@
-foobar
+foobar

tests/goldenfiles/subdir/file1.txt

@@ -1 +1 @@
-File in subdir
+File in subdir

tests/goldenfiles/text_diff1.txt

@@ -1 +1 @@
-Hello world!
+Hello world!

tests/goldenfiles/text_diff2.txt

@@ -1 +1 @@
-foobar
+foobar

tests/goldenfiles/update_env1.txt

@@ -1 +1 @@
-Hello world!
+Hello world!

tests/goldenfiles/update_env2.txt

@@ -1 +1 @@
-foobar
+foobar

tests/test.rs

@@ -20,7 +20,7 @@ fn subdir() {
     let mut mint = Mint::new("tests/goldenfiles");
     let mut file1 = mint.new_goldenfile("subdir/file1.txt").unwrap();
 
-    write!(file1, "File in subdir").unwrap();
+    writeln!(file1, "File in subdir").unwrap();
 }
 
 #[test]
@@ -47,8 +47,8 @@ fn text_match() {
     let mut file1 = mint.new_goldenfile("match1.txt").unwrap();
     let mut file2 = mint.new_goldenfile("match2.txt").unwrap();
 
-    write!(file1, "Hello world!").unwrap();
-    write!(file2, "foobar").unwrap();
+    writeln!(file1, "Hello world!").unwrap();
+    writeln!(file2, "foobar").unwrap();
 }
 
 #[test]
@@ -58,8 +58,8 @@ fn text_diff() {
     let mut file1 = mint.new_goldenfile("text_diff1.txt").unwrap();
     let mut file2 = mint.new_goldenfile("text_diff2.txt").unwrap();
 
-    write!(file1, "Hello world!").unwrap();
-    write!(file2, "monkeybrains").unwrap();
+    writeln!(file1, "Hello world!").unwrap();
+    writeln!(file2, "monkeybrains").unwrap();
 }
 
 #[test]
@@ -75,7 +75,7 @@ fn external_panic() {
     let mut mint = Mint::new("tests/goldenfiles");
     let mut file1 = mint.new_goldenfile("panic.txt").unwrap();
 
-    write!(file1, "new").unwrap();
+    writeln!(file1, "new").unwrap();
     assert!(false);
 }
 
@@ -88,8 +88,8 @@ fn update() {
     let mut file1 = mint.new_goldenfile("update_env1.txt").unwrap();
     let mut file2 = mint.new_goldenfile("update_env2.txt").unwrap();
 
-    write!(file1, "Hello world!").unwrap();
-    write!(file2, "foobar").unwrap();
+    writeln!(file1, "Hello world!").unwrap();
+    writeln!(file2, "foobar").unwrap();
 
     mint.update_goldenfiles()
 }