finalize velocity gradient interpolation test

bfps/test/test_interpolation.py

@@ -34,20 +34,15 @@ def main():
             'r')
     pos0 = ifile['tracers0/state/0'].value
     pos1 = ofile['tracers0/position/0'].value
-    print('maximum position error is ', np.max(np.abs(pos0-pos1) / np.abs(pos0)))
+    assert(np.max(np.abs(pos0-pos1) / np.abs(pos0)) <= 1e-5)
     vort0 = ofile['tracers0/vorticity/0'].value
-    print(vort0)
     vel_gradient = ofile['tracers0/velocity_gradient/0'].value
-    print(vel_gradient)
     vort1 = vort0.copy()
-    vort1[:, 0] = vel_gradient[:, 7] - vel_gradient[:, 5]
-    vort1[:, 1] = vel_gradient[:, 2] - vel_gradient[:, 6]
-    vort1[:, 2] = vel_gradient[:, 3] - vel_gradient[:, 1]
-    print(np.abs(vort0-vort1) / np.abs(vort0))
     vort1[:, 0] = vel_gradient[:, 5] - vel_gradient[:, 7]
     vort1[:, 1] = vel_gradient[:, 6] - vel_gradient[:, 2]
     vort1[:, 2] = vel_gradient[:, 1] - vel_gradient[:, 3]
-    print(np.abs(vort0-vort1) / np.abs(vort0))
+    assert(np.max(np.abs(vort0-vort1) / np.abs(vort0)) <= 1e-5)
+    print('SUCCESS! Interpolated vorticity agrees with vorticity from interpolated velocity gradient.')
     return None
 
 if __name__ == '__main__':