Make rspec more DRY by accessing let variable in describe block

Question

I'm trying to DRY up rspec tests that keeps on declaring let(:createBody) do...end. I thought to take out the let statement and just modify the variable on each block as needed. However the variable (createBody) is not accessible. Added a comment on sample code below to see exactly where I want to modify createBody.

post "Creates object", controller_action: :create do
  ...
  let(:createBody) do
    {
      name: "yes",
      type: "my_type",
      amount_cents: 200,
      parameters: {
        day: "today"
      },
      user_group_ids: [],
      user_ids: []
    }
  end

  # no users or groups
  response 201, "object created" do
    ...

    run_test! do |res|
      # this block works fine and can access createBody
      body = JSON.parse(res.body)
      expect(body["name"]).to eq(createBody[:name])
      expect(body["amount_cents"]).to eq(createBody[:amount_cents])
      expect(body["type"]).to eq(createBody[:type])
    end
  end

  # with users
  response 201, "autocharge rule created" do
    ...

    # want to make some modifications on createBody here, like adding user_ids, but it is out of scope
    
    run_test! do |res|
      # this block works fine and can access createBody
      body = JSON.parse(res.body)
      expect(body["user_ids"]).to match_array(createBody[:user_ids])
    end
  end
  ...
end

Is there a way to achieve this approach? Are there any alternatives?

That variable is only available from within individual examples, as you've seen. What would the goal of modifying it outside of an example be? — Jake Worth, Jun 24 '22 at 17:26
Depending on `createBody`, `run_test!`'s `|res|` (result) would vary. — nakakapagpabagabag, Jun 24 '22 at 17:38
You could create a variable in each spec that modifies `createBody` to merge in the unique parameters for that spec. — Jake Worth, Jun 24 '22 at 17:55
I dont think I follow, could you please elaborate or provide an example. Will check on this again later, currently 3am here. — nakakapagpabagabag, Jun 24 '22 at 18:03
I'm not sure that I understand what the goal is. How are you using `createBody` outside of the example that it would need to be modified? — Jake Worth, Jun 24 '22 at 18:35
The goal is to make changes on `createBody` before executing `run_test!`. `run_test!` would then simulate an api request using `createBody` and it would also have the response data based from the `createBody` used. Having the ability to modify `createBody` before executing `run_test!` gives the flexibility of testing various response status and testing data from the response. — nakakapagpabagabag, Jun 25 '22 at 09:20

O. Larkin · Accepted Answer · 2022-06-25T06:53:35.027

I assume response block works in the same way as context

post "Creates object", controller_action: :create do
  let(:createBody) do
    {
      name: "yes",
      type: "my_type",
      amount_cents: 200,
      parameters: {
        day: "today"
      },
      user_group_ids: [],
      user_ids: user_ids # now we can add a let(:user_ids) to each context
    }
  end

  response 201, "object created" do
    let(:user_ids) { [] } # empty since we're not using it here

    ...

    run_test! do |res|
      # this block works fine and can access createBody
      body = JSON.parse(res.body)
      expect(body["name"]).to eq(createBody[:name])
      expect(body["amount_cents"]).to eq(createBody[:amount_cents])
      expect(body["type"]).to eq(createBody[:type])
    end
  end

  # with users
  response 201, "autocharge rule created" do
    let(:user_ids) { [1, 2, 3] } # add required ids

    ...
    
    run_test! do |res|
      # this block works fine and can access createBody
      body = JSON.parse(res.body)
      expect(body["user_ids"]).to match_array(createBody[:user_ids]) # we can match by user_ids now
    end
  end
  ...
end

@o-larkin your answer led me to the right path. I had to do a `let (:my_user_ids) { [] }` above `let(:createBody) do`. I then had to do `user_ids: my_user_ids` inside the `createBody` block. Then doing `let(:user_ids) { ... }` inside the response blocks allowed me to modify `createBody` before `run_test!` — nakakapagpabagabag, Jun 25 '22 at 09:25

Make rspec more DRY by accessing let variable in describe block

1 Answers1