rust: build integration test for the qemu_api crate

Adjust the integration test to compile with a subset of QEMU object
files, and make it actually create an object of the class it defines.

Follow the Rust filesystem conventions, where tests go in tests/ if
they use the library in the same way any other code would.

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

rust/qemu-api/tests/tests.rs

@@ -0,0 +1,78 @@
+// Copyright 2024, Linaro Limited
+// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use core::ffi::CStr;
+
+use qemu_api::{
+    bindings::*,
+    declare_properties, define_property,
+    definitions::{Class, ObjectImpl},
+    device_class_init, vm_state_description,
+};
+
+#[test]
+fn test_device_decl_macros() {
+    // Test that macros can compile.
+    vm_state_description! {
+        VMSTATE,
+        name: c"name",
+        unmigratable: true,
+    }
+
+    #[repr(C)]
+    #[derive(qemu_api_macros::Object)]
+    pub struct DummyState {
+        pub _parent: DeviceState,
+        pub migrate_clock: bool,
+    }
+
+    #[repr(C)]
+    pub struct DummyClass {
+        pub _parent: DeviceClass,
+    }
+
+    declare_properties! {
+        DUMMY_PROPERTIES,
+            define_property!(
+                c"migrate-clk",
+                DummyState,
+                migrate_clock,
+                unsafe { &qdev_prop_bool },
+                bool
+            ),
+    }
+
+    device_class_init! {
+        dummy_class_init,
+        props => DUMMY_PROPERTIES,
+        realize_fn => None,
+        legacy_reset_fn => None,
+        vmsd => VMSTATE,
+    }
+
+    impl ObjectImpl for DummyState {
+        type Class = DummyClass;
+        const TYPE_INFO: qemu_api::bindings::TypeInfo = qemu_api::type_info! { Self };
+        const TYPE_NAME: &'static CStr = c"dummy";
+        const PARENT_TYPE_NAME: Option<&'static CStr> = Some(TYPE_DEVICE);
+        const ABSTRACT: bool = false;
+        const INSTANCE_INIT: Option<unsafe extern "C" fn(obj: *mut Object)> = None;
+        const INSTANCE_POST_INIT: Option<unsafe extern "C" fn(obj: *mut Object)> = None;
+        const INSTANCE_FINALIZE: Option<unsafe extern "C" fn(obj: *mut Object)> = None;
+    }
+
+    impl Class for DummyClass {
+        const CLASS_INIT: Option<
+            unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut core::ffi::c_void),
+        > = Some(dummy_class_init);
+        const CLASS_BASE_INIT: Option<
+            unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut core::ffi::c_void),
+        > = None;
+    }
+
+    unsafe {
+        module_call_init(module_init_type::MODULE_INIT_QOM);
+        object_unref(object_new(DummyState::TYPE_NAME.as_ptr()) as *mut _);
+    }
+}