Check that formatting is as expected

Author: vincentisambart

test/SourceKit/CodeFormat/indent-available-macro.swift

@@ -1,6 +1,9 @@
 @available(iOS 17, *)
 #Preview("") {
-  UIView()
+UIView()
 }
 
 // RUN: %sourcekitd-test -req=format -line=3 -length=1 %s >%t.response
+// RUN: %FileCheck --strict-whitespace %s <%t.response
+
+// CHECK: key.sourcetext: "    UIView()"