Print format diff to stdout (#1506)

src/subcommand.rs

@@ -383,12 +383,12 @@ impl Subcommand {
           for op in diff.ops() {
             for change in diff.iter_changes(op) {
               let (symbol, color) = match change.tag() {
-                ChangeTag::Delete => ("-", config.color.stderr().diff_deleted()),
-                ChangeTag::Equal => (" ", config.color.stderr()),
-                ChangeTag::Insert => ("+", config.color.stderr().diff_added()),
+                ChangeTag::Delete => ("-", config.color.stdout().diff_deleted()),
+                ChangeTag::Equal => (" ", config.color.stdout()),
+                ChangeTag::Insert => ("+", config.color.stdout().diff_added()),
               };
 
-              eprint!("{}{symbol}{change}{}", color.prefix(), color.suffix());
+              print!("{}{symbol}{change}{}", color.prefix(), color.suffix());
             }
           }
         }

tests/fmt.rs

@@ -45,9 +45,11 @@ test! {
   name: check_found_diff,
   justfile: "x:=``\n",
   args: ("--unstable", "--fmt", "--check"),
-  stderr: "
+  stdout: "
     -x:=``
     +x := ``
+  ",
+  stderr: "
     error: Formatted justfile differs from original.
   ",
   status: EXIT_FAILURE,
@@ -65,10 +67,12 @@ test! {
   name: check_diff_color,
   justfile: "x:=``\n",
   args: ("--unstable", "--fmt", "--check", "--color", "always"),
-  stderr: "
+  stdout: "
     \u{1b}[31m-x:=``
     \u{1b}[0m\u{1b}[32m+x := ``
-    \u{1b}[0m\u{1b}[1;31merror\u{1b}[0m: \u{1b}[1mFormatted justfile differs from original.\u{1b}[0m
+    \u{1b}[0m",
+  stderr: "
+    \u{1b}[1;31merror\u{1b}[0m: \u{1b}[1mFormatted justfile differs from original.\u{1b}[0m
   ",
   status: EXIT_FAILURE,
 }