Improve logic and error messages for file reading and writing with Python code (#4567)

* Fix issues with file reading and writing with Python code

* Change error message, use Workspace.get_path

---------

Co-authored-by: Reinier van der Leer <github@pwuts.nl>

tests/integration/test_execute_code.py

@@ -1,6 +1,7 @@
 import random
 import string
 import tempfile
+from typing import Callable
 
 import pytest
 from pytest_mock import MockerFixture
@@ -10,12 +11,12 @@ from autogpt.config import Config
 
 
 @pytest.fixture
-def config_allow_execute(config: Config, mocker: MockerFixture):
+def config_allow_execute(config: Config, mocker: MockerFixture) -> Callable:
     yield mocker.patch.object(config, "execute_local_commands", True)
 
 
 @pytest.fixture
-def python_test_file(config: Config, random_string):
+def python_test_file(config: Config, random_string) -> Callable:
     temp_file = tempfile.NamedTemporaryFile(dir=config.workspace_path, suffix=".py")
     temp_file.write(str.encode(f"print('Hello {random_string}!')"))
     temp_file.flush()
@@ -34,18 +35,24 @@ def test_execute_python_file(python_test_file: str, random_string: str, config):
     assert result.replace("\r", "") == f"Hello {random_string}!\n"
 
 
-def test_execute_python_file_invalid(config):
+def test_execute_python_file_invalid(config: Config):
     assert all(
         s in sut.execute_python_file("not_python", config).lower()
         for s in ["error:", "invalid", ".py"]
     )
+
+
+def test_execute_python_file_not_found(config: Config):
     assert all(
         s in sut.execute_python_file("notexist.py", config).lower()
-        for s in ["error:", "does not exist"]
+        for s in [
+            "python: can't open file 'notexist.py'",
+            "[errno 2] no such file or directory",
+        ]
     )
 
 
-def test_execute_shell(config_allow_execute, random_string, config):
+def test_execute_shell(config_allow_execute: bool, random_string: str, config: Config):
     result = sut.execute_shell(f"echo 'Hello {random_string}!'", config)
     assert f"Hello {random_string}!" in result