从不同的文件调用 rspec 方法

Question

I am trying to write a class in my code to wrap some of the RSpec calls. However, whenever I try to access rspec things, my class simply doesn't see the methods.

I have the following file defined in spec/support/helper.rb

require 'rspec/mocks/standalone'

module A
  class Helper
    def wrap_expect(dbl, func, args, ret)
      expect(dbl).to receive(func).with(args).and_return(ret)
    end
  end
end

I get a NoMethodError: undefined method 'expect' , despite requiring the correct module. Note that if I put calls to rspec functions before the module, everything is found correctly.

I've tried adding the following like to my spec_helper.rb :

  config.requires << 'rspec/mocks/standalone'

But to no avail.

I managed to use class variables in my class and passing the functions through from the global context, but that solution seems quite extreme. Also I was able to pass in the test context itself and storing it, but I'd rather not have to do that either.

Answer 1

expect functions by default is associated with only rspec-core methods like it before . If you need to have expect inside a method, you can try adding the Rspec matcher class in the helper file.

include RSpec::Matchers

Answer 2

that error because the self which call expect is not the current rspec context RSpec::ExampleGroups , you could check by log the self

module A
  class Helper
    def wrap_expect(dbl, func, args, ret)
      puts self
      expect(dbl).to receive(func).with(args).and_return(ret)
    end
  end
end

# test case
A::Helper.new.wrap_expect(...) # log self: A::Helper

so obviously, A::Helper does not support expect

now you have 2 options to build a helper: (1) a module or (2) a class which init with the current context of test cases:

(1)

module WrapHelper
 def wrap_expect(...)
   puts self # RSpec::ExampleGroups::...
   expect(...).to receive(...)...
 end
end

# test case
RSpec.describe StackOverFlow, type: :model do
  include WrapHelper
  it "...." do
    wrap_expect(...) # call directly 
  end
end

(2)

class WrapHelper
 def initialize(spec)
   @spec = spec 
 end
 
 def wrap_expect(...)
   puts @spec # RSpec::ExampleGroups::...
   @spec.expect(...).to @spec.receive(...)...
 end
end

# test case
RSpec.describe StackOverFlow, type: :model do
  let!(:helper) {WrapHelper.new(self)}
  
  it "...." do
    helper.wrap_expect(...)
  end
end