Today I Learned Notes to self about software development

    Better Rspec tests with shared examples

    25 May 2023

    TIL about shared examples in Rspec!

    They’re primarily good for reducing duplicate code.

    They work well with subject and let.

    This is a made up example:

    describe "Todos" do
  context 'when on the edit page' do
    subject { Todo.create(title: "Day 1", body: "Hello, World!") }
    let(:path) { edit_todo_path(subject) }

    it "displays form" do
      visit path

      expect(page).to have_css("form")
    end
    
    it "redirects after submitting update form" do
      visit path

      click_on "Update #{subject.class}"

      expect(page.current_url).not_to be path
    end
  end
end

    You could write very similar tests for other models.

    With shared examples you could do something like this:

    shared_examples_for "Editing a resource" do
  it "displays form" do
    visit path
    expect(page).to have_css("form")
  end

  it "redirects after submitting update form" do
    visit path
    click_on "Update #{subject.class}"
    expect(page.current_url).not_to be path
  end
end

describe "Todos" do
  context 'when on the edit page' do
    subject { Todo.create(title: "Day 1", body: "Hello, World!") }
    let(:path) { edit_todo_path(subject) }

    it_behaves_like "Editing a resource"
  end
end

    Then in the future when you need a test that does something similar, you can make/reference a a shared example group.

    #rspec

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