add test case for #173, currently unable to reproduce.

backend/LexBoxApi/Controllers/ProjectController.cs

@@ -66,4 +66,22 @@ public async Task<ActionResult<int>> AddLexboxSuffix()
         return await _lexBoxDbContext.Projects.Where(p => !p.Code.EndsWith("-lexbox"))
             .ExecuteUpdateAsync(_ => _.SetProperty(p => p.Code, p => p.Code + "-lexbox"));
     }
+
+    [HttpDelete("project/{id}")]
+    [ProducesResponseType(StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    [ProducesDefaultResponseType]
+    [AdminRequired]
+    public async Task<ActionResult<Project>> DeleteProject(Guid id)
+    {
+        //this project is only for testing purposes. It will delete projects permanently from the database.
+        var project = await _lexBoxDbContext.Projects.FindAsync(id);
+        if (project is null) return NotFound();
+        if (project.RetentionPolicy != RetentionPolicy.Dev) return Forbid();
+        _lexBoxDbContext.Projects.Remove(project);
+        var hgService = HttpContext.RequestServices.GetRequiredService<IHgService>();
+        await hgService.DeleteRepo(project.Code);
+        await _lexBoxDbContext.SaveChangesAsync();
+        return project;
+    }
 }

backend/LexBoxApi/Services/HgService.cs

@@ -28,6 +28,11 @@ await Task.Run(() => CopyFilesRecursively(
         ));
     }
 
+    public async Task DeleteRepo(string code)
+    {
+        await Task.Run(() => Directory.Delete(Path.Combine(_options.Value.RepoPath, code), true));
+    }
+
     private void CopyFilesRecursively(DirectoryInfo source, DirectoryInfo target)
     {
         foreach (DirectoryInfo dir in source.GetDirectories())

backend/LexCore/ServiceInterfaces/IHgService.cs

@@ -7,4 +7,5 @@ public interface IHgService
     Task InitRepo(string code);
     Task<DateTimeOffset?> GetLastCommitTimeFromHg(string projectCode);
     Task<Changeset[]> GetChangesets(string projectCode);
+    Task DeleteRepo(string code);
 }

backend/Testing/ApiTests/NewProjectRaceCondition.cs

@@ -0,0 +1,40 @@
+using System.Text.Json.Nodes;
+using Shouldly;
+
+namespace Testing.ApiTests;
+
+// issue: https://github.com/sillsdev/languageforge-lexbox/issues/173
+[Trait("Category", "Integration")]
+public class NewProjectRaceCondition : ApiTestBase
+{
+    readonly Guid _projectId = Guid.Parse("3e81814d-ce7e-438f-b8e8-beac1cd7596b");
+    [Fact]
+    public async Task CanCreateProjectAndQueryItRightAway()
+    {
+
+        await LoginAs("admin", "pass");
+        await HttpClient.DeleteAsync($"http://{Host}/api/project/project/{_projectId}");
+        await Task.Delay(TimeSpan.FromSeconds(1));
+        var response = await ExecuteGql($$"""
+mutation {
+    createProject(input: {
+        name: "Test race condition",
+        type: FL_EX,
+        id: "{{_projectId}}",
+        code: "test-race-flex",
+        description: "this is just a testing project for testing a race condition",
+        retentionPolicy: DEV
+    }) {
+        project {
+            name
+            changesets {
+                desc
+            }
+        }
+    }
+}
+""");
+        var project = response["data"]!["createProject"]!["project"].ShouldBeOfType<JsonObject>();
+        project["name"]!.GetValue<string>().ShouldBe("test");
+    }
+}

backend/Testing/Services/TestingEnvironmentVariables.cs

@@ -2,7 +2,7 @@ namespace Testing.Services;
 
 public static class TestingEnvironmentVariables
 {
-    public static string ServerHostname = Environment.GetEnvironmentVariable("TEST_SERVER_HOSTNAME") ?? "localhost:5158";
+    public static string ServerHostname = Environment.GetEnvironmentVariable("TEST_SERVER_HOSTNAME") ?? "localhost";
     public static string StandardHgHostname = Environment.GetEnvironmentVariable("TEST_STANDARD_HG_HOSTNAME") ?? "hg.localhost";
     public static string ResumableHgHostname = Environment.GetEnvironmentVariable("TEST_RESUMABLE_HG_HOSTNAME") ?? "resumable.localhost";