def test_deregister_custom_var():
env = Env()
env.register("MY_SPECIAL_VAR", type="path")
env.deregister("MY_SPECIAL_VAR")
assert "MY_SPECIAL_VAR" not in env
env.register("MY_SPECIAL_VAR", type="path")
paths = ["/home/wakka", "/home/wakka/bin"]
env["MY_SPECIAL_VAR"] = paths
env.deregister("MY_SPECIAL_VAR")
# deregistering a variable that has a value set doesn't
# remove it from env;
# the existing variable also maintains its type validation, conversion
assert "MY_SPECIAL_VAR" in env
with pytest.raises(TypeError):
env["MY_SPECIAL_VAR"] = 32
# removing, then re-adding the variable without registering
# gives it only default permissive validation, conversion
del env["MY_SPECIAL_VAR"]
env["MY_SPECIAL_VAR"] = 32
