test: Check close window rendering

tests/ui/error-emitter/auxiliary/close_window.rs

@@ -0,0 +1,4 @@
+pub struct S;
+impl S {
+    fn method(&self) {}
+}

tests/ui/error-emitter/close_window.ascii.stderr

@@ -0,0 +1,14 @@
+error[E0624]: method `method` is private
+  --> $DIR/close_window.rs:9:7
+   |
+LL |     s.method();
+   |       ^^^^^^ private method
+   |
+  ::: $DIR/auxiliary/close_window.rs:3:5
+   |
+LL |     fn method(&self) {}
+   |     ---------------- private method defined here
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0624`.

tests/ui/error-emitter/close_window.rs

@@ -0,0 +1,11 @@
+//@ aux-build:close_window.rs
+//@ revisions: ascii unicode
+//@[unicode] compile-flags: -Zunstable-options --error-format=human-unicode
+
+extern crate close_window;
+
+fn main() {
+   let s = close_window::S;
+    s.method();
+   //[ascii]~^ ERROR method `method` is private
+}

tests/ui/error-emitter/close_window.unicode.stderr

@@ -0,0 +1,14 @@
+error[E0624]: method `method` is private
+   ╭▸ $DIR/close_window.rs:9:7
+   │
+LL │     s.method();
+   ╰╴      ━━━━━━ private method
+   │
+   ⸬ $DIR/auxiliary/close_window.rs:3:5
+   │
+LL │     fn method(&self) {}
+   ╰╴    ──────────────── private method defined here
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0624`.