Cope with test fixtures which have non-static members (#22)

Consumer/Consumer.fsproj

@@ -15,6 +15,7 @@
         </None>
         <Compile Include="TestAppDomain.fs" />
         <Compile Include="TestCaseData.fs" />
+        <Compile Include="TestNonStatic.fs" />
     </ItemGroup>
 
     <ItemGroup>

Consumer/TestNonStatic.fs

@@ -0,0 +1,31 @@
+namespace Consumer
+
+open System.Threading
+open FsUnitTyped
+open NUnit.Framework
+
+[<RequireQualifiedAccess>]
+module NonStaticTestHelpers =
+    let count = ref 0
+
+[<TestFixture>]
+type TestNonStatic () =
+    let count = ref 0
+
+    member this.Thing = "i'm a thing"
+
+    [<Test>]
+    member this.Foo () =
+        Interlocked.Increment NonStaticTestHelpers.count |> ignore<int>
+        Interlocked.Increment count |> ignore<int>
+        this.Thing |> shouldEqual "i'm a thing"
+
+    [<Test>]
+    static member AnotherTest () =
+        Interlocked.Increment NonStaticTestHelpers.count |> ignore<int>
+        1 |> shouldEqual 1
+
+    [<OneTimeTearDown>]
+    member _.TearDown () =
+        count.Value |> shouldEqual 1
+        NonStaticTestHelpers.count.Value |> shouldEqual 2