Example code to run Jest from a Node.js script.

funcs.js

const sum = (n, m) => n + m;

module.exports = { sum };

funcs.spec.js

const { sum } = require("funcs");

describe("Sum", () => {
  it("should be able to sum numbers", async () => {
    expect(sum(2, 2)).toBe(4);
  });

  it("should be able to sum negative numbers", async () => {
    expect(sum(-2, 2)).toBe(0);
  });
});

main.js

const { runCLI } = require("jest");

runCLI(
  {
    collectCoverage: true,
    collectCoverageFrom: "./*.js",
    coveragePathIgnorePatterns: ["./main.js"],
  },
  [""]
);

package.json

{
  "dependencies": {
    "jest": "^27.4.5"
  }
}