BUG: Fixed bounds checking

closes #14

Author: Carwyn Pelley

stratify/_vinterp.pyx

@@ -548,7 +548,7 @@ cdef class _Interpolation(object):
         # Compute the axis in absolute terms.
         fp_axis = (axis + fz_src.ndim) % fz_src.ndim
         zp_axis = fp_axis - (fz_src.ndim - z_src.ndim)
-        if not 0 <= zp_axis < z_src.ndim or axis > z_src.ndim:
+        if (not 0 <= zp_axis < z_src.ndim or axis > fz_src.ndim):
             raise ValueError('Axis {} out of range.'.format(axis))
 
         # Ensure that fz_src's shape is a superset of z_src's.

stratify/tests/test_vinterp.py

@@ -339,14 +339,24 @@ def test_inconsistent_shape(self):
         with self.assertRaisesRegexp(ValueError, emsg):
             vinterp._Interpolation([1, 3], data, zdata, axis=2)
 
-    def test_axis_out_of_bounds(self):
+    def test_axis_out_of_bounds_fz_src_relative(self):
+        # axis is out of bounds as identified by the absolute axis with z_src.
         data = np.empty([5, 4])
         zdata = np.empty([5, 4])
         axis = 4
         emsg = 'Axis {} out of range'
         with self.assertRaisesRegexp(ValueError, emsg.format(axis)):
             vinterp._Interpolation([1, 3], data, zdata, axis=axis)
 
+    def test_axis_out_of_bounds_z_src_absolute(self):
+        # axis is out of bounds as identified by the relative axis with fz_src.
+        data = np.empty([5, 4])
+        zdata = np.empty([3, 5, 4])
+        axis = 0
+        emsg = 'Axis {} out of range'
+        with self.assertRaisesRegexp(ValueError, emsg.format(axis)):
+            vinterp._Interpolation([1, 3], data, zdata, axis=axis)
+
     def test_nd_inconsistent_ndims(self):
         z_target = np.empty((2, 3, 4))
         z_src = np.empty((3, 4))