Fix uninitialized constant error when running model specs

[arku]

What? Why?

When running the model specs with bundle exec rspec spec/models, the following error occurs:

An error occurred while loading ./spec/models/adjustment_metadata_spec.rb.
Failure/Error:
  describe AdjustmentMetadata do
    it "is valid when build from factory" do
      adjustment = create(:adjustment)
      expect(adjustment).to be_valid
    end
  end
NameError:
  uninitialized constant AdjustmentMetadata
# ./spec/models/adjustment_metadata_spec.rb:1:in `<top (required)>'

The PR fixes the issue by requiring spec_helper in the AdjustmentMetadata model spec.

What should we test?

Run bundle exec rspec spec and make sure the tests pass.

Release notes

Changelog Category: Fixed

Discourse thread

Dependencies

Documentation updates

[luisramos0]

Thank you!