Issue #13: pytest added

Tests added to check precondition for the data
To check that the data has at least 4 columns and 4 rows.

sksurgerycore/algorithms/pivot.py

@@ -6,12 +6,32 @@ import numpy as np
 # from numpy.linalg import svd
 
 
-def pivot_calibration(matrices4x4):
+def add(number1, number2):
+    return number1 + number2
+
+def pivot_calibration(matricesNx4x4):
     """
-    The function receive [N, 4, 4] matrices.
+    Performs Pivot Calibration and returns Residual Error.
+
+    1. matricesNx4x4 and moving must be numpy array
+    2. matricesNx4x4 and moving should have 4 columns
+    3. matricesNx4x4 and moving should have at least 4 rows
+
+    :param matricesNx4x4: point set, N x 4 x 4 ndarray
+    :returns: residual_error
+    :raises: TypeError, ValueError
     """
+    if not isinstance(matricesNx4x4, np.ndarray):
+        raise TypeError("matricesNx4x4 is not a numpy array'")
+
+    if not matricesNx4x4.shape[1] == 4:  # pylint: disable=literal-comparison
+        raise ValueError("matricesNx4x4 should have 4 columns per matrix")
+
+    if not matricesNx4x4.shape[0] == 4:  # pylint: disable=literal-comparison
+        raise ValueError("matricesNx4x4 should have 4 rows per matrix")
+
 
-    number_of_matrices = len(matrices4x4)
+    number_of_matrices = len(matricesNx4x4)
 
     size_a = 3 * number_of_matrices, 6
     a_values = np.zeros(size_a, dtype=np.float64)
@@ -23,19 +43,19 @@ def pivot_calibration(matrices4x4):
     b_values = np.zeros(size_b, dtype=np.float64)
 
     for i in range(number_of_matrices):
-        b_values[i * 3 + 0, 0] = -1 * matrices4x4[i, 0, 3]
-        b_values[i * 3 + 1, 0] = -1 * matrices4x4[i, 1, 3]
-        b_values[i * 3 + 2, 0] = -1 * matrices4x4[i, 2, 3]
-
-        a_values[i * 3 + 0, 0] = matrices4x4[i, 0, 0]
-        a_values[i * 3 + 1, 0] = matrices4x4[i, 1, 0]
-        a_values[i * 3 + 2, 0] = matrices4x4[i, 2, 0]
-        a_values[i * 3 + 0, 1] = matrices4x4[i, 0, 1]
-        a_values[i * 3 + 1, 1] = matrices4x4[i, 1, 1]
-        a_values[i * 3 + 2, 1] = matrices4x4[i, 2, 1]
-        a_values[i * 3 + 0, 2] = matrices4x4[i, 0, 2]
-        a_values[i * 3 + 1, 2] = matrices4x4[i, 1, 2]
-        a_values[i * 3 + 2, 2] = matrices4x4[i, 2, 2]
+        b_values[i * 3 + 0, 0] = -1 * matricesNx4x4[i, 0, 3]
+        b_values[i * 3 + 1, 0] = -1 * matricesNx4x4[i, 1, 3]
+        b_values[i * 3 + 2, 0] = -1 * matricesNx4x4[i, 2, 3]
+
+        a_values[i * 3 + 0, 0] = matricesNx4x4[i, 0, 0]
+        a_values[i * 3 + 1, 0] = matricesNx4x4[i, 1, 0]
+        a_values[i * 3 + 2, 0] = matricesNx4x4[i, 2, 0]
+        a_values[i * 3 + 0, 1] = matricesNx4x4[i, 0, 1]
+        a_values[i * 3 + 1, 1] = matricesNx4x4[i, 1, 1]
+        a_values[i * 3 + 2, 1] = matricesNx4x4[i, 2, 1]
+        a_values[i * 3 + 0, 2] = matricesNx4x4[i, 0, 2]
+        a_values[i * 3 + 1, 2] = matricesNx4x4[i, 1, 2]
+        a_values[i * 3 + 2, 2] = matricesNx4x4[i, 2, 2]
 
         a_values[i * 3 + 0, 3] = -1
         a_values[i * 3 + 1, 3] = 0

tests/algorithms/test_pivot.py

+#  -*- coding: utf-8 -*-
+
+# import six
+import numpy as np
+import pytest
+import sksurgerycore.algorithms.pivot as p
+
+
+def test_empty_matrices4x4():
+    with pytest.raises(TypeError):
+        p.pivot_calibration(None)
+
+
+def test_four_columns_matrices4x4():
+    with pytest.raises(ValueError):
+        p.pivot_calibration(np.arange(2, 11, dtype=float).reshape(3, 3))
+
+def test_four_rows_matrices4x4():
+    with pytest.raises(ValueError):
+        p.pivot_calibration(np.arange(2, 11, dtype=float).reshape(3, 3))
+