Fix for input data bug (#5)

* Bug in read_input

* Add test for input data

* Empty input test

Author: Shillaker

pyfaasm/pyfaasm/core.py

@@ -83,7 +83,9 @@ def read_input(input_len):
     _init_host_interface()
     input_len = int(input_len)
     buff = ctypes.create_string_buffer(input_len)
-    return _host_interface.__faasm_read_input(buff, input_len)
+    _host_interface.__faasm_read_input(buff, input_len)
+
+    return buff.value
 
 
 def write_output(output):

pyfaasm/test/test_inputs.py

@@ -0,0 +1,31 @@
+import unittest
+import json
+from pyfaasm.core import (
+    get_input_len,
+    read_input,
+    set_emulator_message,
+)
+
+
+class TestInputs(unittest.TestCase):
+    def test_input_data(self):
+        expected = "blah blah foo bar"
+        msg = {"user": "foo", "function": "bar", "input_data": expected}
+
+        set_emulator_message(json.dumps(msg))
+
+        input_len = get_input_len()
+        self.assertEqual(input_len, len(expected))
+
+        actual_bytes = read_input(input_len)
+        actual = actual_bytes.decode("utf-8")
+
+        self.assertEqual(actual, expected)
+
+    def test_empty_input_data(self):
+        msg = {"user": "foo", "function": "bar"}
+
+        set_emulator_message(json.dumps(msg))
+
+        input_len = get_input_len()
+        self.assertEqual(input_len, 0)