Running Jest using Gulp with code coverage

Jest is a unit test framework that is mainly used for reactjs. Jest is widely used by facebook in their projects.

Add below configuration in gulpfile.js for running Jest unit test cases through gulp

  const gulp = require('gulp');
  const jestcli = require('jest-cli');

  gulp.task('test', () => {  
   jestcli.runCLI({ config: { rootDir: 'test/unit/' } }, '.', (done) => {
    done();
   });
  });

Using command: gulp test, will execute the test cases written under directory 'test/unit'. To have code coverage, we can configure it in package.json file as below:

  "jest": {
    "collectCoverage": true,
    "coverageDirectory": "./test/unit-test-coverage"
  }

Add above config in package.json file. for defining custom directory to create the report, mention the directory in coverageDirectory key, otherwise it will generate at root directory.

How to check if database exists while connecting in HSQLDB

In HSQLDB, if while providing connection string if the database does not exists, it creates a new database. However, lets say if we want to restrict HSQLDB to create new Database and only connect to exists one and if not present then throw back an exception, we can specify a connection property ifexists=true. This will allow only to connect to an existing database and avoid creating new one. Also, if db does not exists it will throw an exception.

 Connection c = DriverManager.getConnection( "jdbc:hsqldb:file:testdb;ifexists=true", "SA", "");