add test workflow

.github/workflows/test.yaml

@@ -0,0 +1,18 @@
+name: Test
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  test:
+    name: Test
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Unit Test (Backend)
+        working-directory: src-tauri
+        run: cargo test