Expose driver base classes via API (#523)

docs/sections/user_guide/api/driver.rst

@@ -0,0 +1,6 @@
+``uwtools.api.driver``
+======================
+
+.. automodule:: uwtools.api.driver
+   :inherited-members:
+   :members:

docs/sections/user_guide/api/index.rst

@@ -5,6 +5,7 @@ API
    chgres_cube
    config
    esg_grid
+   driver
    file
    filter_topo
    fv3

src/uwtools/api/driver.py

@@ -0,0 +1,28 @@
+"""
+API access to the ``uwtools`` driver base classes.
+"""
+
+import importlib
+import sys
+
+_CLASSNAMES = [
+    "Assets",
+    "AssetsCycleBased",
+    "AssetsCycleAndLeadtimeBased",
+    "AssetsTimeInvariant",
+    "Driver",
+    "DriverCycleBased",
+    "DriverCycleAndLeadtimeBased",
+    "DriverTimeInvariant",
+]
+
+
+def _add_classes():
+    m = importlib.import_module("uwtools.drivers.driver")
+    for classname in _CLASSNAMES:
+        setattr(sys.modules[__name__], classname, getattr(m, classname))
+        __all__.append(classname)
+
+
+__all__: list[str] = []
+_add_classes()

src/uwtools/drivers/ww3.py

@@ -14,7 +14,7 @@
 
 class WaveWatchIII(AssetsCycleBased):
     """
-    A library driver for ww3.
+    An assets driver for ww3.
     """
 
     # Workflow tasks

src/uwtools/tests/api/test_driver.py

@@ -0,0 +1,25 @@
+# pylint: disable=missing-function-docstring,protected-access
+
+from inspect import isclass, ismodule
+
+from pytest import mark
+
+from uwtools.api import driver as driver_api
+from uwtools.drivers import driver as driver_lib
+
+
+@mark.parametrize("classname", driver_api._CLASSNAMES)
+def test_driver(classname):
+    assert getattr(driver_api, classname) is getattr(driver_lib, classname)
+
+
+def test_public_attributes():
+    # Check that the module is not accidentally exposing unexpected public attributes. Ignore
+    # private attributes and imported modules and assert that what remains is an intentionally
+    # exposed (driver) class.
+    for name in dir(driver_api):
+        obj = getattr(driver_api, name)
+        if name.startswith("_") or ismodule(obj):
+            continue
+        assert isclass(obj)
+        assert name in driver_api._CLASSNAMES