dragonball: add test utils.

Added some tools for dragonball unit testing.

Signed-off-by: wllenyj <wllenyj@linux.alibaba.com>

src/dragonball/src/lib.rs

@@ -34,6 +34,9 @@ pub mod vm;
 
 mod event_manager;
 mod io_manager;
+
+mod test_utils;
+
 mod vmm;
 
 pub use self::error::StartMicroVmError;

src/dragonball/src/test_utils.rs

@@ -0,0 +1,47 @@
+// Copyright (C) 2022 Alibaba Cloud. All rights reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+#[cfg(test)]
+pub mod tests {
+    use crate::api::v1::InstanceInfo;
+    use crate::vm::{CpuTopology, KernelConfigInfo, Vm, VmConfigInfo};
+    use dbs_utils::epoll_manager::EpollManager;
+    use linux_loader::cmdline::Cmdline;
+    use std::sync::{Arc, RwLock};
+    use vmm_sys_util::tempfile::TempFile;
+
+    pub fn create_vm_for_test() -> Vm {
+        // Call for kvm too frequently would cause error in some host kernel.
+        let instance_info = Arc::new(RwLock::new(InstanceInfo::default()));
+        let epoll_manager = EpollManager::default();
+        let mut vm = Vm::new(None, instance_info, epoll_manager).unwrap();
+        let kernel_file = TempFile::new().unwrap();
+        let cmd_line = Cmdline::new(64);
+        vm.set_kernel_config(KernelConfigInfo::new(
+            kernel_file.into_file(),
+            None,
+            cmd_line,
+        ));
+
+        let vm_config = VmConfigInfo {
+            vcpu_count: 1,
+            max_vcpu_count: 1,
+            cpu_pm: "off".to_string(),
+            mem_type: "shmem".to_string(),
+            mem_file_path: "".to_string(),
+            mem_size_mib: 1,
+            serial_path: None,
+            cpu_topology: CpuTopology {
+                threads_per_core: 1,
+                cores_per_die: 1,
+                dies_per_socket: 1,
+                sockets: 1,
+            },
+            vpmu_feature: 0,
+        };
+        vm.set_vm_config(vm_config);
+        vm.init_guest_memory().unwrap();
+        vm
+    }
+}