[wildcards] code folding tests

Fixes: #56009

Change-Id: Iad1f197388d0b89e9bd9b31cc82a496cf578380b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/371663
Auto-Submit: Phil Quitslund <[email protected]>
Commit-Queue: Brian Wilkerson <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: pq

pkg/analysis_server/test/src/computer/folding_computer_test.dart

@@ -519,6 +519,49 @@ main2/*[1*/() {
     });
   }
 
+  Future<void> test_function_expression_underscore_preWildcards() async {
+    var content = '''
+// /*[0*/
+// @dart = 3.4
+// (pre wildcard-variables)/*0]*/
+
+// Content before
+
+void f/*[1*/() {
+  _/*[2*/(){
+  }/*2]*/
+}/*1]*/
+
+// Content after
+''';
+
+    await _computeRegions(content);
+    expectRegions({
+      0: FoldingKind.FILE_HEADER,
+      1: FoldingKind.FUNCTION_BODY,
+      2: FoldingKind.FUNCTION_BODY,
+    });
+  }
+
+  Future<void> test_function_expression_wildcard() async {
+    var content = '''
+// Content before
+
+void f/*[0*/() {
+  _/*[1*/(){
+  }/*1]*/
+}/*0]*/
+
+// Content after
+''';
+
+    await _computeRegions(content);
+    expectRegions({
+      0: FoldingKind.FUNCTION_BODY,
+      1: FoldingKind.FUNCTION_BODY,
+    });
+  }
+
   Future<void> test_function_with_dart_doc() async {
     var content = '''
 // Content before