Add clippy-test.yml

Check for code quality improvements on all rust source code with
`clippy` in the `test` workspace.

.github/workflows/clippy-test.yml

@@ -0,0 +1,43 @@
+# Run `clippy` on the `test` workspace
+---
+name: Rust - Run Clippy to check lints (test workspace)
+on:
+  pull_request:
+    paths:
+      - 'test/**/*.rs'
+  workflow_dispatch:
+jobs:
+  clippy-check:
+    name: Clippy linting
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Install Protoc
+        uses: arduino/setup-protoc@v1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+
+      - uses: actions-rs/[email protected]
+        with:
+          toolchain: stable
+          components: clippy
+          override: true
+
+      - name: Install build dependencies
+        if: matrix.os == 'ubuntu-latest'
+        run: |
+          sudo apt-get update
+          sudo apt-get install libdbus-1-dev
+
+      - name: Clippy check
+        working-directory: test
+        shell: bash
+        env:
+          RUSTFLAGS: --deny warnings
+        run: |
+          time cargo clippy --locked -- -W clippy::unused_async