Add a ui test with an assertion that has a really long condition.

nnethercote · nnethercote · commit 40ebcb79155e · 2023-10-09T13:47:48.000+11:00
The `\n` in the output is a little surprising. The next commit will deal
with it.
diff --git a/tests/ui/macros/assert-long-condition.rs b/tests/ui/macros/assert-long-condition.rs
@@ -0,0 +1,8 @@
+// run-fail
+// check-run-results
+// ignore-emscripten no processes
+// ignore-tidy-linelength
+
+fn main() {
+    assert!(1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 + 21 + 22 + 23 + 24 + 25 == 0);
+}
diff --git a/tests/ui/macros/assert-long-condition.run.stderr b/tests/ui/macros/assert-long-condition.run.stderr
@@ -0,0 +1,3 @@
+thread 'main' panicked at $DIR/assert-long-condition.rs:7:5:
+assertion failed: 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18\n                                + 19 + 20 + 21 + 22 + 23 + 24 + 25 == 0
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+thread 'main' panicked at $DIR/assert-long-condition.rs:7:5:`
	`2`	`+assertion failed: 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18\n + 19 + 20 + 21 + 22 + 23 + 24 + 25 == 0`
	`3`	+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace