describe('Reader chain', () => {
  const config: Config = {
    database: {
      host: 'localhost',
      port: 5432,
    },
    appName: 'myapp',
  }

  it('gets database config', () => {
    const result = getDatabase()(config)
    expect(result).toEqual({ host: 'localhost', port: 5432 })
  })

  it('builds connection string', () => {
    const result = getConnectionString()(config)
    expect(result).toBe('localhost:5432')
  })

  it('builds full connection string with app name', () => {
    const result = getFullConnectionString()(config)
    expect(result).toBe('myapp@localhost:5432')
  })
})