add unit tests for distribution module

Author: joshuabmoore

tests/test_calculator.py

@@ -8,7 +8,7 @@
 # does the calculator run on module functions (yes/no)?
 @pytest.mark.parametrize("x", [
     "medical", "extreme", "criticality", "correlation", "information", "entropy",
-    "stationarity"])
+    "stationarity", "distribution"])
 def test_module_basic(x):
     # basic checks on medical module
     data = get_dataset(which="sinusoid")