python saddle points

python/saddle-points/saddle_points_test.py

@@ -0,0 +1,82 @@
+"""Tests for the saddle-points exercise
+
+Implementation note:
+The saddle_points function must validate the input matrix and raise a
+ValueError with a meaningful error message if the matrix turns out to be
+irregular.
+"""
+import unittest
+
+from saddle_points import saddle_points
+
+
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.5.0
+
+class SaddlePointsTest(unittest.TestCase):
+    def test_identify_single_saddle_point(self):
+        matrix = [[9, 8, 7], [5, 3, 2], [6, 6, 7]]
+        self.assertEqual(saddle_points(matrix), [{"row": 2, "column": 1}])
+
+    def test_empty_matrix_has_no_saddle_points(self):
+        self.assertEqual(saddle_points([]), [dict()])
+
+    def test_matrix_with_one_elem_has_single_saddle_point(self):
+        matrix = [[1]]
+        self.assertEqual(saddle_points(matrix), [{"row": 1, "column": 1}])
+
+    def test_identify_lack_of_saddle_points_when_there_are_none(self):
+        matrix = [[1, 2, 3], [3, 1, 2], [2, 3, 1]]
+        self.assertEqual(saddle_points(matrix), [dict()])
+
+    def test_identify_multiple_saddle_points_in_column(self):
+        matrix = [[4, 5, 4], [3, 5, 5], [1, 5, 4]]
+        expected = [{"row": 1, "column": 2}, {"row": 2, "column": 2},
+                    {"row": 3, "column": 2}]
+        self.assertEqual(saddle_points(matrix), expected)
+
+    def test_identify_multiple_saddle_points_in_row(self):
+        matrix = [[6, 7, 8], [5, 5, 5], [7, 5, 6]]
+        expected = [{"row": 2, "column": 1}, {"row": 2, "column": 2},
+                    {"row": 2, "column": 3}]
+        self.assertEqual(saddle_points(matrix), expected)
+
+    def test_identify_saddle_point_in_bottom_right_corner(self):
+        matrix = [[8, 7, 9], [6, 7, 6], [3, 2, 5]]
+        expected = [{"row": 3, "column": 3}]
+        self.assertEqual(saddle_points(matrix), expected)
+
+    def test_non_square_matrix_with_2_saddle_points(self):
+        matrix = [[3, 1, 3], [3, 2, 4]]
+        self.assertEqual(saddle_points(matrix), [{"row": 1, "column": 1},
+                                                 {"row": 1, "column": 3}])
+
+    def test_single_column_matrix_has_saddle_point_min_value(self):
+        matrix = [[2], [1], [4], [1]]
+        self.assertEqual(saddle_points(matrix), [{"row": 2, "column": 1},
+                                                 {"row": 4, "column": 1}])
+
+    def test_single_row_matrix_has_saddle_point_in_max_value(self):
+        matrix = [[2, 5, 3, 5]]
+        self.assertEqual(saddle_points(matrix), [{"row": 1, "column": 2},
+                                                 {"row": 1, "column": 4}])
+
+    # Additional tests for this track
+
+    def test_irregular_matrix(self):
+        matrix = [[3, 2, 1], [0, 1], [2, 1, 0]]
+        with self.assertRaisesWithMessage(ValueError):
+            saddle_points(matrix)
+
+    # Utility functions
+    def setUp(self):
+        try:
+            self.assertRaisesRegex
+        except AttributeError:
+            self.assertRaisesRegex = self.assertRaisesRegexp
+
+    def assertRaisesWithMessage(self, exception):
+        return self.assertRaisesRegex(exception, r".+")
+
+
+if __name__ == '__main__':
+    unittest.main()