ci: runsystests under emulator on GH Action

Toward #184/

.github/workflows/emulator_systests.yml

@@ -0,0 +1,41 @@
+name: "Presubmit: build and test wheels"
+
+on:
+  push:
+  #pull_request:
+  #  branches:
+  #    - main
+
+jobs:
+
+  run-systests-under-emulator:
+    runs-on: ubuntu-latest
+
+    steps:
+
+    - name: Checkout
+      uses: actions/checkout@v2
+
+    - name: Install gclould SDK + Bigtable emulator
+      env:
+        BIGTABLE_EMULATOR_HOST: "localhost:8789"
+      run: |
+        apt-get install google-cloud-sdk google-cloud-sdk-bigtable-emulator
+        gcloud components install beta bigtable
+        gcloud beta emulators bigtable start --host-port $BIGTABLE_EMULATOR_HOST
+
+    - name: Set up python
+      uses: actions/setup-python@v2
+      with:
+        python-version: "3.9"
+
+    - name: Install test dependencies
+      run: |
+          python -m pip install nox
+          nox -e system-3.9 --install-only
+
+    - name: Run systests
+      env:
+        BIGTABLE_EMULATOR_HOST: "localhost:8789"
+      run:
+          .nox/system-3.9/bin/py.test -v tests/system