diff --git a/spec/concerns/fieldable_spec.rb b/spec/concerns/fieldable_spec.rb
new file mode 100644
index 000000000..148dce4cc
--- /dev/null
+++ b/spec/concerns/fieldable_spec.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe "Dois", type: :controller do
+  subject { DataciteDoisController.new }
+
+  it "no params" do
+    params = ActionController::Parameters.new
+    expect(subject.fields_from_params(params)).to be_nil
+    expect(subject.fields_hash_from_params(params)).to be_nil
+  end
+
+  it "single value" do
+    params = ActionController::Parameters.new(fields: { dois: "id" })
+    expect(subject.fields_from_params(params)).to eq({ dois: ["id"] }.with_indifferent_access)
+    expect(subject.fields_hash_from_params(params)).to eq({ dois: "id" }.with_indifferent_access)
+  end
+
+  it "multiple values" do
+    params = ActionController::Parameters.new(fields: { dois: "id,subjects" })
+    expect(subject.fields_from_params(params)).to eq({ dois: ["id", "subjects"] }.with_indifferent_access)
+    expect(subject.fields_hash_from_params(params)).to eq({ dois: "id,subjects" }.with_indifferent_access)
+  end
+end