diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
new file mode 100644
index 0000000..2d5484b
--- /dev/null
+++ b/.devcontainer/devcontainer.json
@@ -0,0 +1,6 @@
+{
+  "tasks": {
+    "test": "dotnet test",
+    "build": "dotnet build"
+  }
+}
\ No newline at end of file
diff --git a/ApiStub.FSharp/CE.fs b/ApiStub.FSharp/CE.fs
index 105e41c..589a695 100644
--- a/ApiStub.FSharp/CE.fs
+++ b/ApiStub.FSharp/CE.fs
@@ -8,6 +8,7 @@ open System
 open Microsoft.Extensions.Http
 open Microsoft.AspNetCore.Routing.Template
 open Microsoft.AspNetCore.Routing
+open Microsoft.AspNetCore.Http
 
 /// computation expression module (builder CE), contains `TestClient<T>` that wraps `WebApplicationFactory<T>`
 module CE =
@@ -211,6 +212,10 @@ module CE =
                 s.ConfigureAll<HttpClientFactoryOptions>(fun options ->
                     options.HttpMessageHandlerBuilderActions.Add(fun builder ->
                         //builder.AdditionalHandlers.Add(httpMessageHandler) |> ignore
+
+                        if httpMessageHandler = null then
+                            failwith "no mocks were provided"
+
                         builder.PrimaryHandler <- httpMessageHandler)
 
                     options.HttpClientActions.Add(fun c ->
diff --git a/test/ApiStub.FSharp.Tests.fsproj b/test/ApiStub.FSharp.Tests.fsproj
index 1bc2665..6c300cf 100644
--- a/test/ApiStub.FSharp.Tests.fsproj
+++ b/test/ApiStub.FSharp.Tests.fsproj
@@ -10,6 +10,7 @@
     <Compile Include="BDDTests.fs" />
     <Compile Include="BuilderExtensionsTests.fs" />
     <Compile Include="StubberyTests.fs" />
+    <Compile Include="Issues.fs" />
     <Content Include="swagger.json" />
   </ItemGroup>
   <ItemGroup>
@@ -35,4 +36,4 @@
   <ItemGroup>
     <PackageReference Update="FSharp.Core" Version="6.0.3" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/test/Issues.fs b/test/Issues.fs
new file mode 100644
index 0000000..a3a1f83
--- /dev/null
+++ b/test/Issues.fs
@@ -0,0 +1,44 @@
+namespace ApiStub.FSharp.Tests
+
+open Xunit
+open fsharpintegrationtests
+open Microsoft.AspNetCore.Mvc.Testing
+open Microsoft.Extensions.DependencyInjection
+open Microsoft.AspNetCore.Hosting
+open SwaggerProvider
+open System.Threading.Tasks
+open System.Net.Http
+open System
+open Microsoft.AspNetCore.TestHost
+open Microsoft.Extensions.Http
+open Microsoft.AspNetCore.Routing.Template
+open Microsoft.AspNetCore.Routing.Patterns
+open Microsoft.AspNetCore.Routing
+open System.Net
+open System.Text.Json
+open Microsoft.AspNetCore.Http
+open System.Net.Http.Json
+open Swensen.Unquote
+open ApiStub.FSharp.CE
+open ApiStub.FSharp.BuilderExtensions
+open ApiStub.FSharp.HttpResponseHelpers
+open ApiStub.FSharp
+open ApiStub.FSharp.BDD
+open HttpResponseMessageExtensions
+open Xunit.Abstractions
+
+module IssuesTests =
+
+    let testce = new CE.TestClient<Startup>()
+
+    [<Fact>]
+    let ``test_no_mocks_declared_throws_exception`` () =
+        task {
+            let factory = testce.GetFactory()
+            let client = factory.CreateClient()
+
+            let! response = client.GetAsync("/Hello")
+            Assert.False(response.IsSuccessStatusCode)
+            let! responseString = response.Content.ReadAsStringAsync()
+            Assert.Contains("no mocks were provided", responseString)
+        }