RSpec: 如何通过对象标识比较 have_received 个参数？

Question

我曾经使用 expect(subject/double).to haved_received(:a_method).with(args).exactly(n).times 来测试一个方法是否被调用了一些特定的参数并且被调用了 {n} 次。但是今天它打破了参数是 Comparable 个对象，看看下面的代码：

设置

class A; end

class B
 include Comparable
 attr_reader :val

 def initialize(val)
   @val = val
 end

 def <=>(other)
   self.val <=> other.val
 end
end

class S
 def call(x); end
end

s = S.new
allow(s).to receive(:call)

现在下面的测试通过了普通对象 A

a1 = A.new
a2 = A.new

s.call(a1)
s.call(a2)

expect(s).to have_received(:call).with(a1).exactly(1).times
expect(s).to have_received(:call).with(a2).exactly(1).times

但它因 Comparable 对象 B

而失败

b1 = B.new(0)
b2 = B.new(0)

s.call(b1)
s.call(b2)

expect(s).to have_received(:call).with(b1).exactly(1).times
expect(s).to have_received(:call).with(b2).exactly(1).times

我调试看到rspec匹配器调用宇宙飞船运算符<=>来验证参数，所以它认为b1和b2是相同的

Failure/Error: expect(s).to have_received(:call).with(b1).exactly(1).times
expected: 1 time with arguments:
received: 2 times with arguments:

我应该怎么做才能通过考试？

Answer 1

我的解决方案：使用 the have_attributes matcher 来准确检查对象参数的 object_id

expect(s).to have_received(:call).with(have_attributes(object_id: b1.object_id))
.exactly(1).times

expect(s).to have_received(:call).with(have_attributes(object_id: b2.object_id))
.exactly(1).times

Answer 2

发生这种情况是因为 Comparable 实现了 ==，因此您的对象在 ==:

方面被视为相等

b1 = B.new(0)
b2 = B.new(0)

b1 == b2 #=> true

要根据对象标识设置约束，您可以使用 equal 匹配器：（或其别名 an_object_equal_to / equal_to）

expect(s).to have_received(:call).with(an_object_equal_to(b1)).once

在幕后，这个匹配器调用 equal?:

b1 = B.new(0)
b2 = B.new(0)

b1.equal?(b2) #=> false

RSpec: 如何通过对象标识比较 have_received 个参数？

RSpec: How to compare have_received arguments by object identity?

ruby

rspec

object-identity