Refine test pattern.

Author: ioquatix

test/async/reactor.rb

@@ -134,7 +134,7 @@
 				reactor.print_hierarchy(output, backtrace: true)
 				lines = output.string.lines
 
-				expect(lines).to have_value(be =~ /in .*sleep'/)
+				expect(lines).to have_value(be =~ /in .sleep'/)
 
 				child.stop
 			end