Add a simple Categorical space

tests/test_basic.py

@@ -0,0 +1,22 @@
+#####################################################
+# Copyright (c) Xuanyi Dong [GitHub D-X-Y], 2021.03 #
+#####################################################
+import sys
+import unittest
+import pytest
+from pathlib import Path
+
+lib_dir = (Path(__file__).parent / ".." / "lib").resolve()
+print("library path: {:}".format(lib_dir))
+if str(lib_dir) not in sys.path:
+    sys.path.insert(0, str(lib_dir))
+
+from spaces import Categorical
+
+
+class TestBasicSpace(unittest.TestCase):
+    def test_categorical(self):
+        space = Categorical(1, 2, 3, 4)
+        for i in range(4):
+            self.assertEqual(space[i], i + 1)
+        self.assertEqual("Categorical(candidates=[1, 2, 3, 4])", str(space))