Use github actions to ensure code is formated.

.github/workflows/test.yml

@@ -0,0 +1,37 @@
+name: "Test"
+on:
+  pull_request:
+  push:
+jobs:
+  test-nix:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+          # Nix Flakes doesn't work on shallow clones
+          fetch-depth: 0
+    - uses: cachix/install-nix-action@v16
+      with:
+        nix_path: nixpkgs=channel:nixos-unstable
+        extra_nix_config: |
+          experimental-features = nix-command flakes
+          system-features = nixos-test benchmark big-parallel kvm
+    - run: nix-build
+  test:
+    strategy:
+      matrix:
+        go-version: [ 1.14.x, 1.15.x, 1.16.x ]
+        os: [ ubuntu-latest ]
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Install Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: ${{ matrix.go-version }}
+    - name: Checkout code
+      uses: actions/checkout@v2
+    - name: Format
+      run: if [ "$(gofmt -s -l . | wc -l)" -gt 0 ]; then exit 1; fi
+      if: matrix.os == 'ubuntu-latest'
+    - name: Test
+      run: go test -race ./...