Add one more synthetic env

tests/test_math_adv.py

@@ -15,6 +15,7 @@ if str(lib_dir) not in sys.path:
 
 from datasets import QuadraticFunc
 from datasets import ConstantFunc
+from datasets import DynamicLinearFunc
 from datasets import DynamicQuadraticFunc
 from datasets import ComposedSinFunc
 
@@ -50,3 +51,20 @@ class TestDynamicFunc(unittest.TestCase):
 
         function.set_timestamp(1)
         print(function(2))
+
+    def test_simple_linear(self):
+        timestamps = 30
+        function = DynamicLinearFunc()
+        function_param = dict()
+        function_param[0] = ComposedSinFunc(
+            num=timestamps, num_sin_phase=4, phase_shift=1.0, max_amplitude=1.0
+        )
+        function_param[1] = ConstantFunc(constant=0.9)
+        function.set(function_param)
+        print(function)
+
+        with self.assertRaises(TypeError) as context:
+            function(0)
+
+        function.set_timestamp(1)
+        print(function(2))