fix: accept no options-folder when fetching usage

backend/src/Designer/Controllers/AppDevelopmentController.cs

@@ -547,17 +547,14 @@ public ActionResult GetWidgetSettings(string org, string app)
         [Route("option-list-ids")]
         public ActionResult GetOptionListIds(string org, string app)
         {
-            try
-            {
-                string developer = AuthenticationHelper.GetDeveloperUserName(HttpContext);
-                AltinnAppGitRepository altinnAppGitRepository = _altinnGitRepositoryFactory.GetAltinnAppGitRepository(org, app, developer);
-                string[] optionListIds = altinnAppGitRepository.GetOptionsListIds();
-                return Ok(optionListIds);
-            }
-            catch (LibGit2Sharp.NotFoundException)
+            string developer = AuthenticationHelper.GetDeveloperUserName(HttpContext);
+            AltinnAppGitRepository altinnAppGitRepository = _altinnGitRepositoryFactory.GetAltinnAppGitRepository(org, app, developer);
+            string[] optionListIds = altinnAppGitRepository.GetOptionsListIds();
+            if (optionListIds.Length == 0)
             {
                 return NoContent();
             }
+            return Ok(optionListIds);
         }
 
         [HttpGet("app-version")]

backend/src/Designer/Infrastructure/GitRepository/AltinnAppGitRepository.cs

@@ -798,7 +798,7 @@ public string[] GetOptionsListIds()
             string optionsFolder = Path.Combine(OptionsFolderPath);
             if (!DirectoryExistsByRelativePath(optionsFolder))
             {
-                throw new NotFoundException("Options folder not found.");
+                return [];
             }
 
             string[] fileNames = GetFilesByRelativeDirectoryAscSorted(optionsFolder, "*.json");

backend/tests/Designer.Tests/Controllers/OptionsController/GetOptionListsReferencesTests.cs

@@ -1,9 +1,11 @@
 using System.Collections.Generic;
+using System.IO;
 using System.Net.Http;
 using System.Text.Json;
 using System.Threading.Tasks;
 using Altinn.Studio.Designer.Models.Dto;
 using Designer.Tests.Controllers.ApiTests;
+using Designer.Tests.Utils;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Testing;
 using Xunit;
@@ -14,6 +16,7 @@ public class GetOptionListsReferencesTests : DesignerEndpointsTestsBase<GetOptio
 {
     const string RepoWithUsedOptions = "app-with-options";
     const string RepoWithUnusedOptions = "app-with-layoutsets";
+    const string RepoWithoutOptions = "empty-app";
 
     public GetOptionListsReferencesTests(WebApplicationFactory<Program> factory) : base(factory)
     {
@@ -85,4 +88,25 @@ public async Task GetOptionListsReferences_Returns200Ok_WithEmptyOptionsReferenc
         Assert.Equal(StatusCodes.Status200OK, (int)response.StatusCode);
         Assert.Equivalent("[]", responseBody);
     }
+
+    [Fact]
+    public async Task GetOptionListsReferences_Returns200Ok_WithEmptyOptionsReferences_WhenAppDoesNotHaveOptions()
+    {
+        string targetRepository = TestDataHelper.GenerateTestRepoName();
+        await CopyRepositoryForTest("ttd", RepoWithoutOptions, "testUser", targetRepository);
+        string repoPath = TestDataHelper.GetTestDataRepositoryDirectory("ttd", targetRepository, "testUser");
+        string exampleLayout = @"{ ""data"": {""layout"": []}}";
+        string filePath = Path.Combine(repoPath, "App/ui/form/layouts");
+        Directory.CreateDirectory(filePath);
+        await File.WriteAllTextAsync(Path.Combine(filePath, "exampleLayout.json"), exampleLayout);
+
+        string apiUrl = $"/designer/api/ttd/{targetRepository}/options/usage";
+        using HttpRequestMessage httpRequestMessage = new(HttpMethod.Get, apiUrl);
+
+        using HttpResponseMessage response = await HttpClient.SendAsync(httpRequestMessage);
+        string responseBody = await response.Content.ReadAsStringAsync();
+
+        Assert.Equal(StatusCodes.Status200OK, (int)response.StatusCode);
+        Assert.Equivalent("[]", responseBody);
+    }
 }

backend/tests/Designer.Tests/Infrastructure/GitRepository/AltinnAppGitRepositoryTests.cs

@@ -296,14 +296,14 @@ public Task GetOptionListIds_WithAppThatHasOptionLists_ShouldReturnOptionListPat
         }
 
         [Fact]
-        public Task GetOptionListIds_WithAppThatHasNoOptionLists_ShouldThrowNotFoundException()
+        public void GetOptionListIds_WithAppThatHasNoOptionLists_ShouldReturnEmptyList()
         {
             string org = "ttd";
             string repository = "empty-app";
             string developer = "testUser";
             AltinnAppGitRepository altinnAppGitRepository = PrepareRepositoryForTest(org, repository, developer);
-            Assert.Throws<LibGit2Sharp.NotFoundException>(altinnAppGitRepository.GetOptionsListIds);
-            return Task.CompletedTask;
+            var optionsIds = altinnAppGitRepository.GetOptionsListIds();
+            Assert.Equal([], optionsIds);
         }
 
         [Fact]