Prove we appropriately can handle _elements query parameters

Currently we skip the read interaction and refer to a bug report in the
Spark repository.

Author: kennethmyhra

lib/tests/suites/incendi_elements_search_parameter.rb

@@ -0,0 +1,112 @@
+module Crucible
+  module Tests
+    class ElementsSearchParameterTest < BaseSuite
+
+      def id
+        'ElementsSearchParameterTest'
+      end
+
+      def description
+        'Searching with _elements should return resources containing only the requested elements'
+      end
+
+      def initialize(client1, client2 = nil)
+        super(client1, client2)
+        @tags.append('incendilabs')
+        @category = { id: 'incendilabs', title: 'Incendilabs' }
+        @supported_versions = [:stu3, :r4]
+      end
+
+      def setup
+        @patient = ResourceGenerator.minimal_patient('elements-search-parameter', 'Elements', version_namespace)
+        @patient.gender = 'male'
+        @patient.birthDate = '1974-12-25'
+
+        reply = @client.create(@patient)
+        assert_response_ok(reply)
+        @patient_id = reply.id
+
+        # Sleep to allow the server to index the new Patient before we attempt to search for it.
+        # This only applies if the server uses an asynchronous indexing process.
+        sleep(0.2)
+      end
+
+      def teardown
+        @client.destroy(version_namespace.const_get(:Patient), @patient_id) unless @patient_id.nil?
+      end
+
+      def elements_search_options
+        {
+          search: {
+            compartment: nil,
+            parameters: {
+              '_id' => @patient_id,
+              '_elements' => 'name,birthDate'
+            }
+          }
+        }
+      end
+
+      test 'I_ELEMENTS_001', 'Search with _elements returns only requested Patient elements' do
+        metadata {
+          links "#{BASE_SPEC_LINK}/search.html#elements"
+          links "#{REST_SPEC_LINK}#search"
+          validates resource: 'Patient', methods: ['search']
+        }
+
+        reply = @client.search(version_namespace.const_get(:Patient), elements_search_options)
+
+        assert_response_ok(reply)
+        assert_bundle_response(reply)
+
+        entries = reply.resource.entry || []
+
+        outcome_entries = entries.select do |e|
+          e.resource.is_a?(version_namespace.const_get(:OperationOutcome)) &&
+            e.search&.mode == 'outcome'
+        end
+
+        assert(
+          outcome_entries.empty?,
+          'Expected _elements to be handled as a general search result parameter, but the searchset Bundle contained an OperationOutcome entry with search.mode=outcome',
+          reply.body
+        )
+
+        patient_entries = entries.select do |e|
+          e.resource.is_a?(version_namespace.const_get(:Patient))
+        end
+
+        assert_equal 1, patient_entries.size, 'Expected search by _id and _elements to return exactly one Patient entry.', reply.body
+
+        patient = patient_entries.first.resource
+        assert_equal @patient_id, patient.id, 'Expected the Patient id to be retained even when _elements omits id.', reply.body
+        assert(patient.name && patient.name.any?, 'Expected Patient.name to be retained when _elements includes name.', reply.body)
+        assert(patient.gender.nil?, 'Expected Patient.gender to be omitted when _elements only includes name,birthDate.', reply.body)
+        assert_equal '1974-12-25', patient.birthDate, 'Expected Patient.birthDate to be retained when _elements includes birthDate.', reply.body
+      end
+
+      test 'I_ELEMENTS_002', 'Read with _elements returns only requested Patient elements' do
+        skip 'https://github.com/FirelyTeam/spark/issues/1336'
+
+        metadata {
+          links "#{BASE_SPEC_LINK}/http.html#read"
+          links "#{BASE_SPEC_LINK}/search.html#elements"
+          validates resource: 'Patient', methods: ['read']
+        }
+
+        reply = @client.get(URI::encode("Patient/#{@patient_id}?_elements=name,birthDate"), @client.fhir_headers)
+        reply.resource = @client.parse_reply(version_namespace.const_get(:Patient), @client.default_format, reply)
+
+        assert_response_ok(reply)
+        assert_resource_type(:Patient, reply.resource)
+
+        patient = reply.resource
+        assert_equal @patient_id, patient.id, 'Expected the Patient id to be retained even when _elements omits id.', reply.body
+        assert(patient.name && patient.name.any?, 'Expected Patient.name to be retained when _elements includes name.', reply.body)
+        assert(patient.gender.nil?, 'Expected Patient.gender to be omitted when _elements only includes name,birthDate.', reply.body)
+        assert_equal '1974-12-25', patient.birthDate, 'Expected Patient.birthDate to be retained when _elements includes birthDate.', reply.body
+      end
+
+    end
+  end
+end