diff --git a/tests/test_wave_sim.py b/tests/test_wave_sim.py
index 6615a70..2510c28 100644
--- a/tests/test_wave_sim.py
+++ b/tests/test_wave_sim.py
@@ -11,7 +11,7 @@ def test_xnor2_delays():
     c = np.full((4*16, 1), TMAX, dtype=np.float32)  # 4 waveforms of capacity 16
     c_locs = np.zeros((4,), dtype='int')
     c_caps = np.zeros((4,), dtype='int')
-    h = np.zeros((4, 1), dtype=np.float32)
+    ebuf = np.zeros((4, 1, 2), dtype=np.int32)
 
     for i in range(4): c_locs[i], c_caps[i] = i*16, 16  # 1:1 mapping
     delays = np.zeros((1, 4, 2, 2))
@@ -28,7 +28,7 @@ def test_xnor2_delays():
 
     def wave_assert(inputs, output):
         for i, a in zip(inputs, c.reshape(-1,16)): a[:len(i)] = i
-        wave_eval_cpu(op, c, c_locs, c_caps, h, 0, delays, simctl_int, 0)
+        wave_eval_cpu(op, c, c_locs, c_caps, ebuf, 0, delays, simctl_int, 0, 0)
         for i, v in enumerate(output): np.testing.assert_allclose(c.reshape(-1,16)[2,i], v)
 
     wave_assert([[TMIN,TMAX],[TMIN,TMAX]], [TMIN,TMAX])      # XNOR(1,1) => 1
@@ -44,7 +44,7 @@ def test_nand_delays():
     c = np.full((5*16, 1), TMAX, dtype=np.float32)  # 5 waveforms of capacity 16
     c_locs = np.zeros((5,), dtype='int')
     c_caps = np.zeros((5,), dtype='int')
-    h = np.zeros((5, 1), dtype=np.float32)
+    ebuf = np.zeros((4, 1, 2), dtype=np.int32)
 
     for i in range(5): c_locs[i], c_caps[i] = i*16, 16  # 1:1 mapping
 
@@ -66,7 +66,7 @@ def test_nand_delays():
 
     def wave_assert(inputs, output):
         for i, a in zip(inputs, c.reshape(-1,16)): a[:len(i)] = i
-        wave_eval_cpu(op, c, c_locs, c_caps, h, 0, delays, simctl_int, 0)
+        wave_eval_cpu(op, c, c_locs, c_caps, ebuf, 0, delays, simctl_int, 0, 0)
         for i, v in enumerate(output): np.testing.assert_allclose(c.reshape(-1,16)[4,i], v)
 
     wave_assert([[TMAX,TMAX],[TMAX,TMAX],[TMIN,TMAX],[TMIN,TMAX]], [TMIN,TMAX]) # NAND(0,0,1,1) => 1