embark/dapps/tests/app/test/lib_test_spec.js

/*global artifacts, contract, config, it*/
const assert = require('assert');
const Test2 = artifacts.require('Test2');

config({
  contracts: {
    deploy: {
      "Test2": {},
      "ZAMyLib": {},
      "ZAMyLib2": {
        "deploy": true
      }
    }
  }
});

contract("Test", function() {
  it("should call library correctly", async function() {
    let result = await Test2.methods.testAdd().call();
    assert.strictEqual(parseInt(result, 10), 3);
  });

});