wallaby.js

module.exports = function(wallaby) {
  // Babel, jest-cli and some other modules may be located under
  // react-scripts/node_modules, so need to let node.js know about it
  var path = require("path");
  process.env.NODE_PATH +=
    path.delimiter +
    path.join(__dirname, "node_modules") +
    path.delimiter +
    path.join(__dirname, "node_modules/react-scripts/node_modules");
  require("module").Module._initPaths();

  return {
    files: [
      "src/**/*.+(js|jsx|json|snap|css|less|sass|scss|jpg|jpeg|gif|png|svg)",
      "!src/**/*.test.js?(x)",
      { pattern: "src/index.js", instrument: false },
      { pattern: "src/serviceWorker.js", instrument: false }
    ],
    filesWithNoCoverageCalculated: ["src/index.js", "src/serviceWorker.js"],

    tests: ["src/**/*.test.js?(x)"],

    env: {
      type: "node",
      runner: "node"
    },

    compilers: {
      "**/*.js?(x)": wallaby.compilers.babel({
        presets: ["react-app"]
      })
    },

    setup: wallaby => {
      const jestConfig = require("react-scripts/scripts/utils/createJestConfig")(
        p => require.resolve("react-scripts/" + p)
      );
      Object.keys(jestConfig.transform || {}).forEach(
        k => ~k.indexOf("^.+\\.(js|jsx") && void delete jestConfig.transform[k]
      );
      delete jestConfig.testEnvironment;
      wallaby.testFramework.configure(jestConfig);
    },

    testFramework: "jest"
  };
};