Rename from the rather bland "TestRunner" (#61)

WoofWare.NUnitTestRunner.Lib/List.fs

@@ -0,0 +1,15 @@
+namespace WoofWare.NUnitTestRunner
+
+[<RequireQualifiedAccess>]
+module internal List =
+
+    /// Given e.g. [[1,2],[4,5,6]], returns:
+    /// [1;4] ; [1;5] ; [1;6] ; [2;4] ; [2;5] ; [2;6]
+    /// in some order.
+    /// This is like allPairs but more so.
+    let rec combinations (s : 'a list list) : 'a list list =
+        match s with
+        | [] -> [ [] ]
+        | head :: s ->
+            let sub = combinations s
+            head |> List.collect (fun head -> sub |> List.map (fun tail -> head :: tail))