Move /src/test to /tests

tests/ui/parser/unicode-character-literal.fixed

@@ -0,0 +1,21 @@
+// Regression test for #88684: Improve diagnostics for combining marks
+// in character literals.
+
+// run-rustfix
+
+fn main() {
+    let _spade = "♠️";
+    //~^ ERROR: character literal may only contain one codepoint
+    //~| NOTE: this `♠` is followed by the combining mark `\u{fe0f}`
+    //~| HELP: if you meant to write a `str` literal, use double quotes
+
+    let _s = "ṩ̂̊";
+    //~^ ERROR: character literal may only contain one codepoint
+    //~| NOTE: this `s` is followed by the combining marks `\u{323}\u{307}\u{302}\u{30a}`
+    //~| HELP: if you meant to write a `str` literal, use double quotes
+
+    let _a = 'Å';
+    //~^ ERROR: character literal may only contain one codepoint
+    //~| NOTE: this `A` is followed by the combining mark `\u{30a}`
+    //~| HELP: consider using the normalized form `\u{c5}` of this character
+}