Add DiscreteConditional unit test for markdown printing

python/gtsam/tests/test_DiscreteConditional.py

@@ -0,0 +1,54 @@
+"""
+GTSAM Copyright 2010-2021, Georgia Tech Research Corporation,
+Atlanta, Georgia 30332-0415
+All Rights Reserved
+
+See LICENSE for the license information
+
+Unit tests for Discrete Conditionals.
+Author: Varun Agrawal
+"""
+
+# pylint: disable=no-name-in-module, invalid-name
+
+import unittest
+
+from gtsam import DiscreteConditional, DiscreteKeys
+from gtsam.utils.test_case import GtsamTestCase
+
+
+class TestDiscreteConditional(GtsamTestCase):
+    """Tests for Discrete Conditionals."""
+    def test_markdown(self):
+        """Test whether the _repr_markdown_ method."""
+
+        A = (2, 2)
+        B = (1, 2)
+        C = (0, 3)
+        parents = DiscreteKeys()
+        parents.push_back(B)
+        parents.push_back(C)
+
+        conditional = DiscreteConditional(A, parents,
+                                          "0/1 1/3  1/1 3/1  0/1 1/0")
+        expected = \
+            " $P(A|B,C)$:\n" \
+            "|B|C|0|1|\n" \
+            "|:-:|:-:|:-:|:-:|\n" \
+            "|0|0|0|1|\n" \
+            "|0|1|0.25|0.75|\n" \
+            "|0|2|0.5|0.5|\n" \
+            "|1|0|0.75|0.25|\n" \
+            "|1|1|0|1|\n" \
+            "|1|2|1|0|\n"
+
+        def formatter(x: int):
+            names = ["C", "B", "A"]
+            return names[x]
+
+        actual = conditional._repr_markdown_(formatter)
+        self.assertEqual(actual, expected)
+
+
+if __name__ == "__main__":
+    unittest.main()