ruby 在 MiniTest 的 assert_raises/must_raise 中检查异常消息的预期语法是什么？
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What is the expected syntax for checking exception messages in MiniTest's assert_raises/must_raise?
提问by kfitzpatrick
What is the expected syntax for checking exception messages in MiniTest's assert_raises/must_raise?
在 MiniTest 的assert_raises/ 中检查异常消息的预期语法是什么must_raise？
I'm trying to make an assertion something like the following, where "Foo"is the expected error message:
我正在尝试做出如下断言，"Foo"预期的错误消息在哪里：
proc { bar.do_it }.must_raise RuntimeError.new("Foo")
回答by blowmage
You can use the assert_raisesassertion, or the must_raiseexpectation.
您可以使用assert_raises断言或must_raise期望。
it "must raise" do
assert_raises RuntimeError do
bar.do_it
end
-> { bar.do_it }.must_raise RuntimeError
lambda { bar.do_it }.must_raise RuntimeError
proc { bar.do_it }.must_raise RuntimeError
end
If you need to test something on the error object, you can get it from the assertion or expectation like so:
如果您需要在错误对象上测试某些内容，您可以从断言或期望中获取它，如下所示：
describe "testing the error object" do
it "as an assertion" do
err = assert_raises RuntimeError { bar.do_it }
assert_match /Foo/, err.message
end
it "as an exception" do
err = ->{ bar.do_it }.must_raise RuntimeError
err.message.must_match /Foo/
end
end
回答by Jing Li
To assert exception:
断言异常：
assert_raises FooError do
bar.do_it
end
To assert exception message:
断言异常消息：
As per API doc, assert_raisesreturns the exception matched so you can check the message, attributes, etc.
根据API doc，assert_raises返回匹配的异常，以便您可以检查消息、属性等。
exception = assert_raises FooError do
bar.do_it
end
assert_equal('Foo', exception.message)
回答by Developer
Minitest does not provide (yet) you a way to check the actual exception message. But you could add a helper method that does it and extend ActiveSupport::TestCaseclass to use everywhere in your rails test suite, e.g.:
in test_helper.rb
Minitest 没有提供（还）你一种检查实际异常消息的方法。但是您可以添加一个辅助方法来完成它并扩展ActiveSupport::TestCase类以在您的 Rails 测试套件中的任何地方使用，例如：test_helper.rb
class ActiveSupport::TestCase
def assert_raises_with_message(exception, msg, &block)
block.call
rescue exception => e
assert_match msg, e.message
else
raise "Expected to raise #{exception} w/ message #{msg}, none raised"
end
end
and use it in your tests like:
并在您的测试中使用它，例如：
assert_raises_with_message RuntimeError, 'Foo' do
code_that_raises_RuntimeError_with_Foo_message
end
回答by Kostas Rousis
To add some more recent developments, there have been some discussionson adding assert_raises_with_messageto minitest in the past without much luck.
为了添加一些最近的发展，过去有一些关于添加assert_raises_with_message到 minitest 的讨论，但运气不佳。
Currently, there is a promising pull requestwaiting to be merged. If and when it gets merged, we will be able to use assert_raises_with_messagewithout having to define it ourselves.
目前，有一个有希望的拉取请求等待合并。如果并且当它合并时，我们将能够使用assert_raises_with_message而无需自己定义它。
In the meanwhile, there is this handy little gem named minitest-bonus-assertionswhich defines exactly that method, along with few others, so that you can use it out of the box. See the docsfor more information.
同时，有一个名为minitest-bonus-assertions 的方便的小宝石，它准确定义了该方法以及其他一些方法，因此您可以开箱即用。有关更多信息，请参阅文档。
