Is there a way to test subsystems (and only subsystems)?

class CowsayTool(NpxToolBase):
    options_scope = "cowsay"
    name = "Cowsay"
    # Intentionally older version.
    default_version = "cowsay@1.4.0"
    help = "The Cowsay utility for printing cowsay messages"

I want to ensure that the version option is present, but the

create_subsystem

utility doesn't seem to do any checking to see if fields exist or not:

cowsaytool = create_subsystem(CowsayTool, versionXYZ="cowsay@1.5.0")

My hope was to do something like this:

rule_runner.set_options(["--backend-packages=['pants.backend.experimental.javascript']", "--cowsay-version='cowsay@1.5.0'"])

and then somehow get the subsystem and verify that the version was picked up correctly. Would I only be able to do this via the

run_pants

mechanism (which seems heavy for what I want)

can do that and then request the subsystem

rule_runner.request(MySubsystem, [])

🤯

Yea, you will need the queryrule

Neat! Thanks!

@pytest.fixture
def rule_runner() -> RuleRunner:
    return RuleRunner(
        rules=[
            *nodejs.rules(),
            *CowsayTool.rules(),
            QueryRule(CowsayTool, []),
        ],
    )

def test_installing(rule_runner: RuleRunner):
    rule_runner.set_options(["--backend-packages=['pants.backend.experimental.javascript']", "--cowsay-version=cowsay@1.5.0"])
    tool = rule_runner.request(CowsayTool, [])
    assert tool.default_version == "cowsay@1.4.0"
    assert tool.version == "cowsay@1.5.0"

cc @ancient-vegetable-10556 ^

@wide-midnight-78598 this (gets a typecheck error because of missing the) is a tediousness arising from MyPy not liking

@memoized_classmethod

Thanks @ancient-vegetable-10556 - I figured it was because of memoized_classmethod, but didn't know if ignoring the error was cool beans or not

Yeah, the solution is to either fix

@memoized

so that it works with

@classmethod

and

@staticmethod

, or to get a mypy plugin to understand the situation

👍 Done!

In case you haven’t already, keeping the

ignore

as tightly scoped as possible is the best practice

),  # type: ignore[call-arg]

?

exactly

Yep, always. Even ignoring stuff like this gives me the queasies, so as tightly scoped as possible 🙂