在ruby测试中使用assert_raise

I'm creating a testing file for a ruby program that finds factorials of given numbers. All of my tests run well except I get an error with my string and negative number tests that should raise exceptions. I'm not entirely sure of the syntax for raise exception, I've read the docs.

我正在为ruby程序创建一个测试文件，该程序可以找到给定数字的阶乘。我的所有测试都运行良好，除了我的字符串错误和负数测试应该引发异常。我不完全确定引发异常的语法，我已经阅读了文档。

this is my code for the factorial program itself, n is the number thats supposed to be passed:

这是我的阶乘程序本身的代码，n是应该传递的数字：

if n.is_a?(Integer) == false
raise 'strings are not acceptable'
end


if n < 0
raise 'negatives are not acceptable'
end

the test case in my test file are as follows:

我的测试文件中的测试用例如下：

def test_negative
factorial(-1)
assert_raise do
end
end

def test_string
factorial('hello')
assert_raise do
end
end

both of my tests come back as errors while my other 3, that test normal numbers, come back as passed. I'm new to ruby but I would just want a pass after assert_raise do as my actual error message is in my factorial program right?

我的两个测试都会以错误的形式返回，而我的其他3个测试正常的数字则会以错误的方式返回。我是ruby的新手但是我想在assert_raise之后想要传递，因为我的实际错误信息在我的析法程序中吗？

1 个解决方案

#1

in your first test case, it will not return an error because -1 is also considered as an Integer

在第一个测试用例中，它不会返回错误，因为-1也被视为整数

#irb output
2.0.0-p247 :003 > a = -1
 => -1 
2.0.0-p247 :004 > a.is_a?(Integer)
 => true

and in your second case, when you pass a string, it will error even before going inside your condition as you are trying to compare string with an integer

在你的第二种情况下，当你传递一个字符串时，即使在你进入你的条件之前它也会出错，因为你试图将字符串与一个整数进行比较

#irb outout
2.0.0-p247 :007 > "hello" < 0
ArgumentError: comparison of String with 0 failed
    from (irb):7:in `<'
    from (irb):7

and off topic, you could write

在主题上，你可以写

if n.is_a?(Integer) == false
  raise 'strings are not acceptable'
end

as (more ruby way :))

作为（更红宝石的方式:)）

raise 'strings are not acceptable' unless n.is_a?(Integer)

#1