Introduce static USB output driver boundary

tests/test_usb_output_driver_native.py

@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+import shutil
+import subprocess
+from pathlib import Path
+
+
+def host_compiler() -> str:
+    compiler = shutil.which("c++") or shutil.which("g++")
+    assert compiler is not None, "a host C++ compiler is required"
+    return compiler
+
+
+def test_usb_output_driver_contracts(tmp_path: Path) -> None:
+    root = Path(__file__).resolve().parents[1]
+    compiler = host_compiler()
+    backends = (
+        ("uart", []),
+        ("bluepad32", ["-DSWITCH_PICO_BLUEPAD32=1"]),
+    )
+    for backend, backend_definitions in backends:
+        for instance_count in range(1, 5):
+            executable = (
+                tmp_path
+                / f"usb_output_driver_{backend}_{instance_count}_test"
+            )
+            result = subprocess.run(
+                [
+                    compiler,
+                    "-std=c++17",
+                    "-Wall",
+                    "-Wextra",
+                    "-Werror",
+                    "-pedantic",
+                    f"-DSWITCH_PICO_HID_INSTANCE_COUNT={instance_count}",
+                    "-DSWITCH_PICO_ADAPTER_FEASIBILITY=1",
+                    *backend_definitions,
+                    f"-I{root / 'tests' / 'native_stubs'}",
+                    f"-I{root}",
+                    str(root / "tests" / "usb_output_driver_test.cpp"),
+                    str(root / "switch_pro_driver.cpp"),
+                    str(root / "usb_output_driver.cpp"),
+                    str(root / "xinput_driver.cpp"),
+                    str(root / "switch_haptics.cpp"),
+                    "-o",
+                    str(executable),
+                ],
+                check=False,
+                cwd=root,
+                text=True,
+                capture_output=True,
+            )
+            assert result.returncode == 0, result.stderr
+            _ = subprocess.run([str(executable)], check=True, cwd=root)