testingSQL.js

const testQuery = async query => {
  const pool = new sql.ConnectionPool({ // ... //})

  try {
    await pool.connect()
    return await pool.request().query(`
      BEGIN TRANSACTION
      ${query}
      ROLLBACK TRANSACTION
    `)
  } finally {
    await pool.close()
  }
}

export const selectMaxRetailPriceMSSQL = `
    SELECT TOP 1 MasterRetailPrice
    FROM UpcCollisionReport
    ORDER BY MasterRetailPrice DESC
`

it('Should return maximum MasterRetailPrice', async () => {
  const {recordset} = await testQuery(`
      -- Initializing database state
      TRUNCATE TABLE UpcCollisionReport;
      INSERT INTO UpcCollisionReport (MasterRetailPrice) 
      VALUES (3), (5), (1), (2), (4);
      ${selectMaxRetailPriceMSSQL} 
  `)
  expect(recordset).toStrictEqual([
    expect.objectContaining({MasterRetailPrice: 5}),
  ])
})