Reformulate the synthetic codes

tests/test_synthetic_env.py

@@ -0,0 +1,30 @@
+#####################################################
+# Copyright (c) Xuanyi Dong [GitHub D-X-Y], 2021.04 #
+#####################################################
+# pytest tests/test_synthetic_env.py -s             #
+#####################################################
+import sys, random
+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 datasets import ConstantGenerator, SinGenerator
+from datasets import SyntheticDEnv
+
+
+class TestSynethicEnv(unittest.TestCase):
+    """Test the synethtic environment."""
+
+    def test_simple(self):
+        mean_generator = SinGenerator()
+        std_generator = ConstantGenerator(constant=0.5)
+
+        dataset = SyntheticDEnv([mean_generator], [[std_generator]])
+        print(dataset)
+        for timestamp, tau in dataset:
+            assert tau.shape == (5000, 1)