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/meson.build

@@ -14,11 +14,31 @@ _qemu_api_rs = static_library(
     '--cfg', 'MESON',
     # '--cfg', 'feature="allocator"',
   ],
-  dependencies: [
-    qemu_api_macros,
-  ],
 )
 
 qemu_api = declare_dependency(
   link_with: _qemu_api_rs,
+  dependencies: qemu_api_macros,
 )
+
+# Rust executables do not support objects, so add an intermediate step.
+rust_qemu_api_objs = static_library(
+    'rust_qemu_api_objs',
+    objects: [libqom.extract_all_objects(recursive: false),
+              libhwcore.extract_all_objects(recursive: false)])
+
+test('rust-qemu-api-integration',
+    executable(
+        'rust-qemu-api-integration',
+        'tests/tests.rs',
+        override_options: ['rust_std=2021', 'build.rust_std=2021'],
+        rust_args: ['--test'],
+        install: false,
+        dependencies: [qemu_api, qemu_api_macros],
+        link_whole: [rust_qemu_api_objs, libqemuutil]),
+    args: [
+        '--test',
+        '--format', 'pretty',
+    ],
+    protocol: 'rust',
+    suite: ['unit', 'rust'])