Add test for python interface

tests/test_purepython.py

@@ -0,0 +1,46 @@
+import unittest
+from python_workflow_definition.purepython import load_workflow_json
+
+function_str = """
+def get_prod_and_div(x, y):
+    return {"prod": x * y, "div": x / y}
+
+
+def get_sum(x, y):
+    return x + y
+
+
+def get_square(x):
+    return x ** 2
+"""
+
+workflow_str = """
+{
+  "version": "0.1.0",
+  "nodes": [
+    {"id": 0, "type": "function", "value": "workflow.get_prod_and_div"},
+    {"id": 1, "type": "function", "value": "workflow.get_sum"},
+    {"id": 2, "type": "function", "value": "workflow.get_square"},
+    {"id": 3, "type": "input", "value": 1, "name": "x"},
+    {"id": 4, "type": "input", "value": 2, "name": "y"},
+    {"id": 5, "type": "output", "name": "result"}
+  ],
+  "edges": [
+    {"target": 0, "targetPort": "x", "source": 3, "sourcePort": null},
+    {"target": 0, "targetPort": "y", "source": 4, "sourcePort": null},
+    {"target": 1, "targetPort": "x", "source": 0, "sourcePort": "prod"},
+    {"target": 1, "targetPort": "y", "source": 0, "sourcePort": "div"},
+    {"target": 2, "targetPort": "x", "source": 1, "sourcePort": null},
+    {"target": 5, "targetPort": null, "source": 2, "sourcePort": null}
+  ]
+}"""
+
+class TestPurePython(unittest.TestCase):
+    def test_pure_python(self):
+        with open("workflow.py", "w") as f:
+            f.write(function_str)
+
+        with open("workflow.json", "w") as f:
+            f.write(workflow_str)
+
+        self.assertEqual(load_workflow_json(file_name="workflow.json"), 6.25)