Add test cases for updatable concern

spec/support/concerns/updatable.rb

@@ -0,0 +1,52 @@
+RSpec.shared_examples "it has updates" do |document_type, example_name|
+  let(:content_store_response) { GovukSchemas::Example.find(document_type, example_name:) }
+
+  before do
+    content_store_response["public_updated_at"] = "2024-07-16T12:36:44Z"
+    content_store_response["details"]["first_public_at"] = "2024-05-23T00:00:00.000+01:00"
+    content_store_response["details"]["change_history"] = [
+      {
+        "note" => "Added the PDF version of the case study.",
+        "public_timestamp" => "2024-06-13T14:33:09.000+01:00",
+      },
+      {
+        "note" => "First published.",
+        "public_timestamp" => "2024-05-23T00:00:00.000+01:00",
+      },
+    ]
+  end
+
+  it "knows its updated" do
+    expect(described_class.new(content_store_response).updated).to eq "2024-07-16T12:36:44Z"
+  end
+
+  it "knows its history" do
+    expect(described_class.new(content_store_response).history).to eq([
+      {
+        display_time: "2024-06-13T14:33:09.000+01:00",
+        note: "Added the PDF version of the case study.",
+        timestamp: "2024-06-13T14:33:09.000+01:00",
+      },
+      {
+        display_time: "2024-05-23T00:00:00.000+01:00",
+        note: "First published.",
+        timestamp: "2024-05-23T00:00:00.000+01:00",
+      },
+    ])
+  end
+
+  context "when there are no updates" do
+    before do
+      content_store_response["public_updated_at"] = nil
+      content_store_response["details"]["first_public_at"] = nil
+    end
+
+    it "returns nil for updated" do
+      expect(described_class.new(content_store_response).updated).to be_falsey
+    end
+
+    it "returns an empty array for history" do
+      expect(described_class.new(content_store_response).history).to eq([])
+    end
+  end
+end