test: add test coverage for passing a json-formatted pdl program

We already support this (since yaml can embed json), but it seems worthwhile having an explicit test for this.

Signed-off-by: Nick Mitchell <[email protected]>

Author: starpit

tests/test_hello.py

@@ -1,3 +1,5 @@
+import json
+
 import pytest
 
 from pdl.pdl import exec_str
@@ -49,6 +51,11 @@ def test_hello():
     assert text == "Hello, world!\nThis is your first prompt descriptor!\n"
 
 
+def test_hello_json():
+    result = exec_str(json.dumps(hello))
+    assert result == "Hello, world!\nThis is your first prompt descriptor!\n"
+
+
 def repeat(n):
     state = InterpreterState()
     data = Program.model_validate(repeat_data(n))