ruby-on-rails - 首先 RSPEC 测试，确保值为 1 或 -1

Question

这里是新程序员。我是一名学生，正在研究我的项目，该项目是 Reddit 的克隆版。目前，我已被介绍给 RSPEC。我必须开始编写自己的模型测试以用于进一步的练习。有问题的模型没有创建，它将在下一个任务中。有人可以检查我是否做对了吗？

In the next checkpoint, we'll add a Vote model. This model will feature an inclusion validation. Inclusion validation ensures that a vote's value attribute is either 1 or -1. If a vote is initialized with any other value, it will not save.

1. Create VoteSpec:

spec/models/vote_spec.rb

describe Vote do
  describe "validations" do
    describe "value validation" do
      it "only allows -1 or 1 as values" do
        # your expectations here
      end
    end
  end
end

Write a spec that asserts the validations work as expected.

Use RSpec's expect().to eq() syntax. As you may recall from the specs in the Ruby exercises, you can assert that something should equal false or true.

You won't be able to run the tests because we haven't generated the model we're testing.

下面是我的实现:

describe Vote do
  describe "validations" do

    before do     
      2.times { @vote.create(value: 1) }
      3.times { @vote.create(value: -1) }
      2.times { @vote.create(value: 3) }
    end

    describe "value validation" do 
      it "only allows -1 or 1 as values" do
        expect ( @vote.value ).to eq(-1)
      end

      it "only allows -1 or 1 as values" do
        expect ( @vote.value ).to eq(1)
      end
    end
  end
end

最好的问候。

编辑:这是一个修订:

describe Vote do
  describe "validations" do

    before do     
      2.times { Vote.create(value: 1) }
      3.times { Vote.create(value: 0) }
      2.times { Vote.create(value: 3) }
    end

    describe "value validation" do 
      it "only allows -1 as value" do
        expect ( @vote.value ).to eq(-1)
      end
      it "only allows 1 as value" do
        expect ( @vote.value ).to eq(1)
      end

      it "it prohibits other values" do
        expect( @vote.value ).to_not be_valid
      end
    end
  end
end

我也试过这段代码，它一开始有效，但现在在下一个任务中失败了:

require 'rails_helper'

  describe Vote do
   describe "value validation" do

      it "allows -1" do
        value = Vote.create(value: -1)
        expect(value).to be_valid
      end

      it "allows +1" do
        value = Vote.create(value: +1)
        expect(value).to be_valid
      end

      it "prohibits other values" do
        value = Vote.create(value: 0)
        expect(value).to_not be_valid
      end

    end
end

▶ rspec spec
...FFF

Failures:

  1) Vote value validation allows -1
     Failure/Error: value = Vote.create(value: -1)
     NoMethodError:
       undefined method `update_rank' for nil:NilClass
     # ./app/models/vote.rb:12:in `update_post'
     # ./spec/models/vote_spec.rb:7:in `block (3 levels) in <top (required)>'

  2) Vote value validation allows +1
     Failure/Error: value = Vote.create(value: +1)
     NoMethodError:
       undefined method `update_rank' for nil:NilClass
     # ./app/models/vote.rb:12:in `update_post'
     # ./spec/models/vote_spec.rb:12:in `block (3 levels) in <top (required)>'

  3) Vote value validation prohibits other values
     Failure/Error: expect(value).to eq(false)

       expected: false
            got: #<Vote id: nil, value: 0, user_id: nil, post_id: nil, created_at: nil, updated_at: nil>

       (compared using ==)
     # ./spec/models/vote_spec.rb:18:in `block (3 levels) in <top (required)>'

Finished in 0.30485 seconds (files took 3.28 seconds to load)
6 examples, 3 failures

Failed examples:

rspec ./spec/models/vote_spec.rb:6 # Vote value validation allows -1
rspec ./spec/models/vote_spec.rb:11 # Vote value validation allows +1
rspec ./spec/models/vote_spec.rb:16 # Vote value validation prohibits other values

Answer 1

在这种稍微特殊的情况下，您可以只使用绝对值。

 it "only allows -1 or 1 as values" do
    expect ( @vote.value.abs ).to eq(1)
 end