circuitpython/tests/micropython/viper_globals.py

# test that viper functions capture their globals context

gl = {}

exec(
    """
@micropython.viper
def f():
    return x
""",
    gl,
)

# x is not yet in the globals, f should not see it
try:
    print(gl["f"]())
except NameError:
    print("NameError")

# x is in globals, f should now see it
gl["x"] = 123
print(gl["f"]())