feat: Add first test workflow

Part of #2

.github/workflows/tests.yml

@@ -0,0 +1,44 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  configure:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v27
+      - name: Build matrix json
+        uses: workflow/nix-shell-action@v3
+        with:
+          script: |
+            node ./tools/ci/generate_matrix.js
+
+      - name: Set matrix data
+        id: set-matrix
+        run: echo "matrix=$(jq -c . < ./tools/ci/workflow-matrix.json)" >> $GITHUB_OUTPUT
+
+  build:
+    name: Build & Run
+    needs: configure
+    strategy:
+      matrix: ${{ fromJson(needs.configure.outputs.matrix) }}
+    runs-on: ${{ matrix.runner }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v27
+      - name: Build then run
+        uses: workflow/nix-shell-action@v3
+        with:
+          script: |
+            bazel run //:filc

tools/ci/.gitignore

@@ -0,0 +1 @@
+workflow-matrix.json

tools/ci/generate_matrix.js

@@ -0,0 +1,16 @@
+const fs = require("node:fs");
+
+const OUTPUT_FILE = __dirname + "/workflow-matrix.json";
+
+const runners = ["ubuntu-latest", "macos-latest", "windows-latest"];
+
+let result = [];
+
+for (let runner of runners) {
+    result.push({
+        runner,
+    });
+}
+
+fs.writeFileSync(OUTPUT_FILE, JSON.stringify({includes: result}));
+

tools/nix/default.nix

@@ -3,4 +3,5 @@
 [
   (import ./pinned-bazel.nix { inherit pkgs; })
   (import ./pinned-clang.nix { inherit pkgs; })
+  (import ./pinned-nodejs.nix { inherit pkgs; })
 ]

tools/nix/pinned-nodejs.nix

@@ -0,0 +1,5 @@
+{ pkgs }:
+
+[
+  pkgs.nodejs_22
+]