tests incompatible with older mmcore

[tlambert03]

this isn't likely to be something we come across much if ever, but I just ran tests on an older windows setup, without running mmcore install and saw this error:

tests\test_prop_widget.py ..................F
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> captured log >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
DEBUG    pymmcore-plus:_util.py:104 using MM path from user install: C:\Users\talley\AppData\Local\pymmcore-plus\pymmcore-plus\mm\Micro-Manager_2.0.3_20231023       
DEBUG    pymmcore-plus:_mmcore_plus.py:305 setting adapter search paths: ['C:\\Users\\talley\\AppData\\Local\\pymmcore-plus\\pymmcore-plus\\mm\\Micro-Manager_2.0.3_20231023']
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> traceback >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 

dev = 'Camera', prop = 'MaximumExposureMs', qtbot = <pytestqt.qtbot.QtBot object at 0x000001715D562080>

    @pytest.mark.parametrize("dev, prop", dev_props)
    def test_property_widget(dev, prop, qtbot):
        wdg = PropertyWidget(dev, prop, mmcore=CORE)
        qtbot.addWidget(wdg)
        if CORE.isPropertyReadOnly(dev, prop) or prop in (
            "SimulateCrash",
            "Trigger",
            "AsyncPropertyLeader",
        ):
            return

        start_val = CORE.getProperty(dev, prop)
        _assert_equal(wdg.value(), start_val)

        # make sure that setting the value via the widget updates core
        if allowed := CORE.getAllowedPropertyValues(dev, prop):
            val = allowed[-1]
        elif CORE.getPropertyType(dev, prop) in (PropertyType.Integer, PropertyType.Float):
            # these are just numbers that work for the test config devices
            _vals = {
                "TestProperty": 1,
                "Photon Flux": 50,
                "TestProperty1": 0.01,
                "TestProperty3": 0.002,
                "OnCameraCCDXSize": 20,
                "OnCameraCCDYSize": 20,
                "FractionOfPixelsToDropOrSaturate": 0.05,
            }
            val = _vals.get(prop, 1)
        else:
            val = "some string"

        before = wdg.value()
        wdg.setValue(val)

        strict_init = hasattr(CORE, "isFeatureEnabled") and CORE.isFeatureEnabled(
            "StrictInitializationChecks"
        )
        if CORE.isPropertyPreInit(dev, prop) and strict_init:
            # as of pymmcore 10.7.0.71.0, setting pre-init properties
            # after the device has been initialized does nothing.
            _assert_equal(wdg.value(), before)
            return

>       _assert_equal(wdg.value(), val)

tests\test_prop_widget.py:74:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  

a = 10000.0, b = 1

    def _assert_equal(a, b):
        try:
>           assert float(a) == float(b)
E           assert 10000.0 == 1.0
E            +  where 10000.0 = float(10000.0)
E            +  and   1.0 = float(1)

tests\test_prop_widget.py:25: AssertionError

I believe it might be an MMCore incompatibility (Micro-Manager_2.0.3_20231023) ... but will look into it later