node/test/addons-napi/test_exception/test.js

'use strict';

const common = require('../../common');
const test_exception = require(`./build/${common.buildType}/test_exception`);
const assert = require('assert');
const theError = new Error('Some error');
function throwTheError() {
  throw theError;
}
let caughtError;

// Test that the native side successfully captures the exception
let returnedError = test_exception.returnException(throwTheError);
assert.strictEqual(theError, returnedError);

// Test that the native side passes the exception through
assert.throws(
  () => {
    test_exception.allowException(throwTheError);
  },
  function(err) {
    return err === theError;
  },
  'Thrown exception was allowed to pass through unhindered'
);

// Test that the exception thrown above was marked as pending
// before it was handled on the JS side
assert.strictEqual(test_exception.wasPending(), true,
                   'VM was marked as having an exception pending' +
                   ' when it was allowed through');

// Test that the native side does not capture a non-existing exception
returnedError = test_exception.returnException(common.mustCall());
assert.strictEqual(undefined, returnedError,
                   'Returned error should be undefined when no exception is' +
                   ` thrown, but ${returnedError} was passed`);

// Test that no exception appears that was not thrown by us
try {
  test_exception.allowException(common.mustCall());
} catch (anError) {
  caughtError = anError;
}
assert.strictEqual(undefined, caughtError,
                   'No exception originated on the native side, but' +
                   ` ${caughtError} was passed`);

// Test that the exception state remains clear when no exception is thrown
assert.strictEqual(test_exception.wasPending(), false,
                   'VM was not marked as having an exception pending' +
                   ' when none was allowed through');