embark/test_apps/test_app/test/lib_test_spec.js

contract("Test", function() {
  before(function(done) {
    this.timeout(0);
    var contractsConfig = {
      "Test2": {
      },
      "ZAMyLib": {
      },
      "ZAMyLib2": {
        "deploy": true
      }
    };

    EmbarkSpec.deployAll(contractsConfig, () => { done() });
  });

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

});