Test suite

[thesoftwarephilosopher]

This builds on #62 and (potentially) finishes #23 to add integration tests.

After this PR, scenarios in deal-generator.txt will have IDs like W1siMjQ1NDgyMiIsW11dXQ==.

Using these IDs, we can generate tests like this:

$ npm run generate-test -- W1siMjQ1NDgyMiIsW11dXQ==

Which will print something like this, suitable for pasting into the test suite:

it(`describe test`, () => {
  const { events, actions } = runDealGenerator({
    group: [['L2169473', []], ['2479625', ['AT-131949332[2479625]', 'AT-97165138[2479625]']]],
    records: [
      testLicense("L2169473", "2013-01-21", "EVALUATION", "inactive"),
      testLicense("2479625", "2013-01-23", "COMMERCIAL", "active"),
      testTransaction("2479625", "2020-04-07", "COMMERCIAL", "Upgrade", "AT-97165138", 411),
      testTransaction("2479625", "2021-03-25", "COMMERCIAL", "Renewal", "AT-131949332", 274)
    ],
  });
  expect(events).toEqual([
    ['purchase', 'L2169473', '2479625'],
    ['upgrade', 'AT-97165138[2479625]'],
    ['renewal', 'AT-131949332[2479625]']
  ]);
  expect(actions).toEqual([
    {
      Create: {
        dealStage: 'CLOSED_WON',
        addonLicenseId: '2479625',
        transactionId: null,
        closeDate: '2013-01-23',
        amount: 0
      }
    },
    {
      Create: {
        dealStage: 'CLOSED_WON',
        addonLicenseId: '2479625',
        transactionId: 'AT-97165138',
        closeDate: '2020-04-07',
        amount: 411
      }
    },
    {
      Create: {
        dealStage: 'CLOSED_WON',
        addonLicenseId: '2479625',
        transactionId: 'AT-131949332',
        closeDate: '2021-03-25',
        amount: 274
      }
    }
  ]);
});

This only tests the deal-generation phase of the engine. But it is one of the most vital and complex parts of the engine, which is why this task focused on that. The only other big part of the engine we could test is the license matcher. That has so far only been tested with a combination of trial and error, and saving extreme amounts of logs, but it has been very thoroughly tested. It will be much harder to test on fake data than the deal generator, but it's probably still possible if/when we want to add tests for it.