add (failing) prism to jani test

tests/storage/test_prism.py

@@ -0,0 +1,12 @@
+import stormpy
+import stormpy.logic
+from helpers.helper import get_example_path
+import pytest
+
+class TestPrism:
+    def test_prism_to_jani(self):
+        program = stormpy.parse_prism_program(get_example_path("dtmc", "die.pm"))
+        orig_properties = stormpy.parse_properties_for_prism_program("P=? [F \"two\"]", program)
+        assert len(orig_properties) == 1
+        jani_model, new_properties = program.to_jani(orig_properties)
+        assert len(new_properties) == len(orig_properties)