Add initial tests

Author: MunifTanjim

src/index.test.js

@@ -0,0 +1,87 @@
+const MongoDBEngine = require('../').default;
+const { MongoDBDatabaseEngine } = require('../');
+
+jest.setTimeout(10 * 1000);
+
+jest.mock('perf_hooks');
+
+const baseVersion = '0';
+const getAdvisoryLockId = (databaseName, ...names) => {
+  return [String(databaseName.length), String(names.join().length)];
+};
+const getUserInfo = () => Promise.resolve(`Jest`);
+
+const databaseName = 'synor';
+const collectionName = 'test_record';
+const params = `synor_migration_record_collection=${collectionName}`;
+const uri = `mongodb://mongo:mongo@127.0.0.1:27017/${databaseName}?${params}`;
+
+describe('module exports', () => {
+  test('default export exists', () => {
+    expect(typeof MongoDBEngine).toBe('function');
+  });
+
+  test('named export exists', () => {
+    expect(typeof MongoDBDatabaseEngine).toBe('function');
+  });
+
+  test('default and named exports are same', () => {
+    expect(MongoDBEngine).toBe(MongoDBDatabaseEngine);
+  });
+});
+
+describe('initialization', () => {
+  let dbUri;
+  const helpers = {
+    baseVersion,
+    getAdvisoryLockId,
+    getUserInfo
+  };
+
+  beforeEach(() => {
+    dbUri = uri;
+    helpers.baseVersion = baseVersion;
+    helpers.getAdvisoryLockId = getAdvisoryLockId;
+    helpers.getUserInfo = getUserInfo;
+  });
+
+  test.each([undefined, null, 0])('throws if uri is %s', uri => {
+    expect(() => MongoDBDatabaseEngine(uri, helpers)).toThrow();
+  });
+
+  test('throws if uri is empty', () => {
+    dbUri = ' ';
+    expect(() => MongoDBDatabaseEngine(dbUri, helpers)).toThrow();
+  });
+
+  describe('helpers validation', () => {
+    beforeEach(() => {
+      helpers.getAdvisoryLockId = getAdvisoryLockId;
+      helpers.getUserInfo = getUserInfo;
+    });
+
+    test(`throws if getAdvisoryLockId is missing`, () => {
+      delete helpers.getAdvisoryLockId;
+      expect(() => MongoDBDatabaseEngine(dbUri, helpers)).toThrow();
+    });
+
+    test(`throws if getAdvisoryLockId is not function`, () => {
+      helpers.getAdvisoryLockId = '';
+      expect(() => MongoDBDatabaseEngine(dbUri, helpers)).toThrow();
+      helpers.getAdvisoryLockId = null;
+      expect(() => MongoDBDatabaseEngine(dbUri, helpers)).toThrow();
+    });
+
+    test(`throws if getUserInfo is missing`, () => {
+      delete helpers.getUserInfo;
+      expect(() => MongoDBDatabaseEngine(dbUri, helpers)).toThrow();
+    });
+
+    test(`throws if getUserInfo is not function`, () => {
+      helpers.getUserInfo = '';
+      expect(() => MongoDBDatabaseEngine(dbUri, helpers)).toThrow();
+      helpers.getUserInfo = null;
+      expect(() => MongoDBDatabaseEngine(dbUri, helpers)).toThrow();
+    });
+  });
+});