add specs for mobile route

modules/mobile/spec/requests/mobile/v0/user/preferred_name_spec.rb

@@ -64,6 +64,18 @@
             end
           end
         end
+
+        it 'invalidates the cache for the mpi-profile-response', :aggregate_failures do
+          preferred_name = VAProfile::Models::PreferredName.new(text: 'Pat')
+          VCR.use_cassette('mobile/va_profile/post_preferred_name_success', erb: { csd: }) do
+            VCR.use_cassette('mobile/demographics/logingov') do
+              expect_any_instance_of(User).to receive(:invalidate_mpi_cache)
+              put('/mobile/v0/user/preferred_name', params: preferred_name.to_h, headers: sis_headers)
+
+              expect(response).to have_http_status(:no_content)
+            end
+          end
+        end
       end
 
       context 'when text is blank' do
@@ -108,6 +120,18 @@
             end
           end
         end
+
+        it 'invalidates the cache for the mpi-profile-response', :aggregate_failures do
+          preferred_name = VAProfile::Models::PreferredName.new(text: 'Pat')
+          VCR.use_cassette('mobile/va_profile/post_preferred_name_success', erb: { csd: }) do
+            VCR.use_cassette('mobile/demographics/logingov') do
+              expect_any_instance_of(User).to receive(:invalidate_mpi_cache)
+              put('/mobile/v0/user/preferred_name', params: preferred_name.to_h, headers: sis_headers)
+
+              expect(response).to have_http_status(:no_content)
+            end
+          end
+        end
       end
 
       context 'when text is blank' do