init build & test flow

.github/workflows/build.yml

@@ -0,0 +1,65 @@
+name: build
+on:
+  pull_request:
+  push:
+jobs:
+  build:
+    strategy:
+      matrix:
+        os:
+          - ubuntu-latest
+          - macos-11
+        nix:
+          - name: 2.5.1
+            url: https://releases.nixos.org/nix/nix-2.5.1/install
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v2.3.5
+      - uses: cachix/install-nix-action@v15
+        with:
+          install_url: ${{ matrix.nix.url }}
+          extra_nix_config: |
+            experimental-features = nix-command flakes
+
+      - name: enable binary cache
+        uses: cachix/cachix-action@v10
+        with:
+          name: statix
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - run: nix flake check
+
+      - name: build statix
+        run: nix build -L
+
+      - name: build and install statix with flake-compat
+        run: nix-env -if default.nix
+
+  tests:
+    strategy:
+      matrix:
+        os:
+          - ubuntu-latest
+        nix:
+          - name: 2.5.1
+            url: https://releases.nixos.org/nix/nix-2.5.1/install
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v2.3.5
+
+      - uses: cachix/install-nix-action@v15
+        with:
+          install_url: ${{ matrix.nix.url }}
+          extra_nix_config: |
+            experimental-features = nix-command flakes
+
+      - uses: cachix/cachix-action@v10
+        with:
+          name: statix
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - name: set up pinned nixpkgs
+        run: echo "NIX_PATH=nixpkgs=$(nix-instantiate --eval flake-compat.nix -A defaultNix.inputs.nixpkgs.outPath | sed 's|\"||g')" >> $GITHUB_ENV
+
+      - run: nix-shell --run "cargo test"
+