Add controller test

test/Altinn.App.Api.Tests/Controllers/OptionsControllerTests.cs

@@ -0,0 +1,55 @@
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.Extensions.DependencyInjection;
+using System.Net;
+using Xunit;
+using Altinn.App.Core.Features;
+using Altinn.App.Core.Models;
+using FluentAssertions;
+
+namespace Altinn.App.Api.Tests.Controllers
+{
+    public class OptionsControllerTests : ApiTestBase, IClassFixture<WebApplicationFactory<Program>>
+    {
+        public OptionsControllerTests(WebApplicationFactory<Program> factory) : base(factory)
+        {
+        }
+
+        [Fact]
+        public async Task Get_ShouldReturnParametersInHeader()
+        {
+            OverrideServicesForThisTest = (services) =>
+            {
+                services.AddTransient<IAppOptionsProvider, DummyProvider>();
+            };
+
+            string org = "tdd";
+            string app = "contributer-restriction";
+            HttpClient client = GetRootedClient(org, app);
+
+            string url = $"/{org}/{app}/api/options/test";
+            HttpResponseMessage response = await client.GetAsync(url);
+
+            var headerValue = response.Headers.GetValues("Altinn-DownstreamParameters");
+            response.StatusCode.Should().Be(HttpStatusCode.OK);
+            headerValue.Should().Contain("lang=nb");
+        }
+    }
+
+    public class DummyProvider : IAppOptionsProvider
+    {
+        public string Id => "test";
+
+        public Task<AppOptions> GetAppOptionsAsync(string language, Dictionary<string, string> keyValuePairs)
+        {
+            AppOptions appOptions = new AppOptions()
+            {
+                Parameters = new Dictionary<string, string>()
+                {
+                    { "lang", "nb" }
+                }
+            };
+
+            return Task.FromResult(appOptions);
+        }
+    }
+}