考虑一个导出连接到互联网并返回结果的子例程的模块:
unit module A;
sub download is export {
"result from internet" # Not the actual implementation, obviously.
}
另一个导入并调用该子例程的模块:
use A; # imports &download into this lexical scope
unit module B;
sub do-something is export {
download().uc ~ "!!" # Does something which involves calling &download
}
现在我想为模块编写单元测试B
.
但我不希望测试真正连接到互联网;我希望他们使用子例程的模拟版本download
这是由我的测试脚本控制的:
use Test;
plan 2;
use B;
my $mock-result;
my &mock-download = -> { $mock-result }
# ...Here goes magic code that installs &mock-download
# as &download in B's lexical scope...
$mock-result = "fake result";
is do-something(), "FAKE RESULT!!", "do-something works - 1";
$mock-result = "foobar";
is do-something(), "FOOBAR!!", "do-something works - 2";
问题是缺少覆盖子的魔术代码download
...
在 Perl 5 中,我认为使用 glob 赋值可以很容易地实现这一点,或者在以下命令的帮助下甚至更好子::覆盖 https://metacpan.org/pod/Sub::Override or 测试::模拟模块 https://metacpan.org/pod/Test::MockModule.
但在 Perl 6 中,模块的词法范围B
编译完成后关闭,因此在测试脚本运行时不再可以修改(如果我错了,请纠正我)。所以这个方法看起来不太可能。
那么,如何在 Perl 6 中解决这一任务呢?
IE。如何编写单元测试B::do-something
,而不让它调用真实的A::download
?