Add dual-controller AIO USB transport

tests/test_switch_pro_descriptors_native.py

@@ -0,0 +1,87 @@
+from __future__ import annotations
+
+import shutil
+import subprocess
+from pathlib import Path
+
+
+def compile_descriptor_test(
+    root: Path,
+    compiler: str,
+    output: Path,
+    expected_count: int,
+    configured_count: int | None,
+) -> subprocess.CompletedProcess[str]:
+    command = [
+        compiler,
+        "-std=c++17",
+        "-Wall",
+        "-Wextra",
+        "-Werror",
+        "-pedantic",
+        f"-DEXPECTED_HID_INSTANCE_COUNT={expected_count}",
+    ]
+    if configured_count is not None:
+        command.append(f"-DSWITCH_PICO_HID_INSTANCE_COUNT={configured_count}")
+    command.extend(
+        [
+            f"-I{root}",
+            str(root / "tests" / "switch_pro_descriptors_test.cpp"),
+            "-o",
+            str(output),
+        ]
+    )
+    return subprocess.run(
+        command,
+        check=False,
+        cwd=root,
+        text=True,
+        capture_output=True,
+    )
+
+
+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_default_descriptor_contract_is_single_hid(tmp_path: Path) -> None:
+    root = Path(__file__).resolve().parents[1]
+    executable = tmp_path / "switch_pro_descriptors_default_test"
+    result = compile_descriptor_test(root, host_compiler(), executable, 1, None)
+    assert result.returncode == 0, result.stderr
+    subprocess.run([str(executable)], check=True, cwd=root)
+
+
+def test_explicit_single_descriptor_contract(tmp_path: Path) -> None:
+    root = Path(__file__).resolve().parents[1]
+    executable = tmp_path / "switch_pro_descriptors_single_test"
+    result = compile_descriptor_test(root, host_compiler(), executable, 1, 1)
+    assert result.returncode == 0, result.stderr
+    subprocess.run([str(executable)], check=True, cwd=root)
+
+
+def test_dual_descriptor_contract(tmp_path: Path) -> None:
+    root = Path(__file__).resolve().parents[1]
+    executable = tmp_path / "switch_pro_descriptors_dual_test"
+    result = compile_descriptor_test(root, host_compiler(), executable, 2, 2)
+    assert result.returncode == 0, result.stderr
+    subprocess.run([str(executable)], check=True, cwd=root)
+
+
+def test_unsupported_hid_instance_counts_fail_to_compile(tmp_path: Path) -> None:
+    root = Path(__file__).resolve().parents[1]
+    compiler = host_compiler()
+    for unsupported_count in (0, 3):
+        executable = tmp_path / f"switch_pro_descriptors_invalid_{unsupported_count}"
+        result = compile_descriptor_test(
+            root,
+            compiler,
+            executable,
+            unsupported_count,
+            unsupported_count,
+        )
+        assert result.returncode != 0, (
+            f"unsupported HID instance count {unsupported_count} compiled successfully"
+        )