[test] [python] Add test_case

test/python_unit/test_case.py

+import unittest
+import numpy as np
+
+class TestCase(unittest.TestCase):
+    def assertApprox(self, a, b, epsilon=1e-6):
+        return self.assertTrue(np.allclose(a, b, epsilon), "%s !~= %s" % (a, b))
+