test(linux-client): move linux-group test out of integration tests (#4692)

Closes #4669 

This should stop the problem of `linux-group` failing because of trying
to test an older release that doesn't have the right CLI features

---------

Co-authored-by: Jamil <jamilbk@users.noreply.github.com>
Co-authored-by: Thomas Eizinger <thomas@eizinger.io>

.github/workflows/_integration_tests.yml

@@ -106,7 +106,6 @@ jobs:
           direct-download-roaming-network,
           dns-failsafe, # Uses the default DNS control method
           dns-nm,
-          # linux-group,  # Stub, doesn't run Firezone code yet. (broken compat test)
           relay-graceful-shutdown,
           relayed-curl-api-down,
           relayed-curl-api-restart,

.github/workflows/_rust.yml

@@ -119,3 +119,25 @@ jobs:
       - name: Run smoke tests (Windows)
         if: ${{ runner.os == 'Windows' }}
         run: bash ../../scripts/tests/smoke-test-gui-windows.sh
+
+  headless-client:
+    name: headless-client-${{ matrix.test }}-${{ matrix.runs-on }}
+    strategy:
+      fail-fast: false
+      matrix:
+        # TODO: Add Windows as part of issue #3782
+        runs-on: [ubuntu-20.04, ubuntu-22.04]
+        test: [linux-group]
+    runs-on: ${{ matrix.runs-on }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/setup-rust
+      - run: cargo build -p firezone-headless-client
+        env:
+          CONNLIB_LOG_UPLOAD_INTERVAL_SECS: 300
+        name: "cargo build"
+        shell: bash
+      - run: scripts/tests/${{ matrix.test }}.sh
+        name: "test script"
+        shell: bash
+        working-directory: ./

scripts/tests/linux-group.sh

@@ -16,10 +16,9 @@ function print_debug_info {
 
 trap print_debug_info EXIT
 
-# Copy the Linux Client out of its container
-docker compose exec client cat firezone-linux-client > "$BINARY_NAME"
-chmod u+x "$BINARY_NAME"
-sudo mv "$BINARY_NAME" "/usr/bin/$BINARY_NAME"
+# Copy the Linux Client out of the build dir
+ls . ./rust ./rust/target ./rust/target/debug
+sudo cp "rust/target/debug/firezone-headless-client" "/usr/bin/$BINARY_NAME"
 
 sudo cp "scripts/tests/systemd/$SERVICE_NAME.service" /usr/lib/systemd/system/