added WENO flux test

This test exposed a bug (#19 (closed)), so it's marked xfail for now.

test.py

@@ -17,6 +17,63 @@ from pyopencl.tools import (  # noqa
 import utilities as u
 
 
+@pytest.mark.xfail
+@pytest.mark.parametrize(("gen_fluxes_str,char_fluxes_pos_str,char_fluxes_neg_str,"
+    "combined_metric,R_str,flux_expected_str"), [
+        ("4 11.2 8 8 46.4,1 2.6 1 1 7.1",
+            ("1.09071563 1.23015152 1.23015152 7.52305259 0.232956271,"
+                "0.467376796 -0.6627417 -0.6627417 1.47953026 0.312527304"),
+            ("-0.168354897 -0.0585786438 -0.0585786438 -0.727493464 -0.306026299,"
+                "-0.0672231577 0.248528137 0.248528137 -0.107250611 -0.374562227"),
+            1.0,
+            ("1 0 0 0.45781246 0.45781246,"
+                "1.58578644 0 0 1.43309957 0.0188860081,"
+                "1.58578644 1.41421356 0 0.725992789 0.725992789,"
+                "1.58578644 0 1.41421356 0.725992789 0.725992789,"
+                "3.77207794 2.24264069 2.24264069 5.57860029 3.3359596"),
+            "4.35371022 12.2479485 8.99522344 8.99522344 51.3903927"),
+        ("-1 2.6 1 1 -7.1,-4 11.2 8 8 -46.4",
+            ("0.0672231577 0.248528137 0.248528137 0.374562227 0.107250611,"
+                "0.168354897 -0.0585786438 -0.0585786438 0.306026299 0.727493464"),
+            ("-0.467376796 -0.6627417 -0.6627417 -0.312527304 -1.47953026,"
+                "-1.09071563 1.23015152 1.23015152 -0.232956271 -7.52305259"),
+            1.0,
+            ("1 0 0 0.45781246 0.45781246,"
+                "-1.58578644 0 0 -0.0188860081 -1.43309957,"
+                "-1.58578644 1.41421356 0 -0.725992789 -0.725992789,"
+                "-1.58578644 0 1.41421356 -0.725992789 -0.725992789,"
+                "3.77207794 -2.24264069 -2.24264069 3.3359596 5.57860029"),
+            "-4.35371022 12.2479485 8.99522344 8.99522344 -51.3903927")
+    ])
+def test_weno_flux_uniform_grid(
+        ctx_factory, gen_fluxes_str, char_fluxes_pos_str, char_fluxes_neg_str,
+        combined_metric, R_str, flux_expected_str):
+    prg = u.get_weno_program_with_root_kernel("weno_flux")
+    queue = u.get_queue(ctx_factory)
+
+    nvars = 5
+
+    gen_fluxes = u.expand_to_6(
+            u.transposed_array_from_string(gen_fluxes_str))
+    char_fluxes_pos = u.expand_to_6(
+            u.transposed_array_from_string(char_fluxes_pos_str))
+    char_fluxes_neg = u.expand_to_6(
+            u.transposed_array_from_string(char_fluxes_neg_str))
+    R = u.array_from_string(R_str)
+    flux_dev = u.empty_array_on_device(queue, nvars)
+
+    prg(queue, nvars=nvars,
+            generalized_fluxes=gen_fluxes,
+            characteristic_fluxes_pos=char_fluxes_pos,
+            characteristic_fluxes_neg=char_fluxes_neg,
+            combined_frozen_metrics=combined_metric,
+            R=R,
+            flux=flux_dev)
+
+    flux_expected = u.array_from_string(flux_expected_str)
+    u.compare_arrays(flux_dev.get(), flux_expected)
+
+
 @pytest.mark.slow
 @pytest.mark.parametrize(("states_str,fluxes_str,R_inv_str,wavespeeds_str,"
         "fluxes_pos_expected_str,fluxes_neg_expected_str"), [