Add test for signal functions

test/test_runner.ml

@@ -39,4 +39,5 @@ let () =
     ; "base: complex", Unit_base_complex.test_set
     ; "base: ndarray core", Unit_base_ndarray_core.test_set
     ; "base: linalg", Unit_linalg_solver.test_set
+    ; "base: signal", Unit_signal.test_set
     ; ("algodiff matrix", Unit_algodiff_matrix.[ Reverse.test; Forward.test ]) ]

test/unit_signal.ml

@@ -0,0 +1,54 @@
+(*Used unit_dense_ndarray test code as reference*)
+open Bigarray
+open Owl
+open Owl_signal
+
+module M = Owl_dense_ndarray_generic
+
+
+let ndarray = Alcotest.testable (fun _p (_x : (float, float64_elt) M.t) -> ()) M.equal
+
+let blackman_reference = M.zeros Float64 [|4|]
+let hamming_reference = M.zeros Float64 [|4|]
+let hann_reference = M.zeros Float64 [|4|]       
+
+let _ = 
+  M.set blackman_reference [|0|] 0.;
+  M.set blackman_reference [|1|] 0.63;
+  M.set blackman_reference [|2|] 0.63;
+  M.set blackman_reference [|3|] 0.;
+  M.set hamming_reference [|0|] 0.08;
+  M.set hamming_reference [|1|] 0.77;
+  M.set hamming_reference [|2|] 0.77;
+  M.set hamming_reference [|3|] 0.08;	
+  M.set hann_reference [|0|] 0.;
+  M.set hann_reference [|1|] 0.75;
+  M.set hann_reference [|2|] 0.75;
+  M.set hann_reference [|3|] 0.;
+
+(*a module with functions to test*)
+module To_test = struct
+  let blackman () = 
+    let b = blackman 4 in
+    let max_err = (Arr.map2 (fun x y -> x -. y) blackman_reference b |> Arr.abs |> Arr.max |> Arr.get) [|0|] in
+    max_err < 1e-5
+
+  let hamming () = 
+    let h = hamming 4 in
+    let max_err = (Arr.map2 (fun x y -> x -. y) hamming_reference h |> Arr.abs |> Arr.max |> Arr.get) [|0|] in
+    max_err < 1e-5
+
+  let hann () = 
+    let h = hann 4 in
+    let max_err = (Arr.map2 (fun x y -> x -. y) hann_reference h |> Arr.abs |> Arr.max |> Arr.get) [|0|] in
+    max_err < 1e-5
+end
+
+let blackman () = Alcotest.(check bool) "blackman" true (To_test.blackman ())
+
+let hamming () = Alcotest.(check bool) "hamming" true (To_test.hamming ())
+
+let hann () = Alcotest.(check bool) "hann" true (To_test.hann ())
+
+let test_set = 
+  [ "blackman", `Slow, blackman; "hamming", `Slow, hamming; "hann", `Slow, hann ]