Note: The two-digit line numbers on the very left edge of the listing are for explanation purposes; they don't appear in the code.
注意:清单左端的两位数行号仅用于解释目的;它们不出现在代码中。
2
Putting this all together yields a flexible test class that verifies two scenarios: a sunny-day path and an edge case where no definition is provided, as shown in Listing 7.