public void DeleteSalary_WhenNotExists()
        {
            var dao = new PostgresDataAccessObjectService(dbContext);

            var coll = dao.GetAllSalaries();

            Assert.Empty(coll);

            dao.DeleteSalary(1);

            coll = dao.GetAllSalaries();
            Assert.Empty(coll);
        }
        public async Task DeleteSalary_WhenExists()
        {
            await dbContext.Salaries.AddAsync(new Salary { SalaryId = 1, Value = 100, TimePeriod = "some", EmployeeId = 1 });

            await dbContext.Salaries.AddAsync(new Salary { SalaryId = 2, Value = 200, TimePeriod = "some2", EmployeeId = 1 });

            await dbContext.SaveChangesAsync();

            var dao = new PostgresDataAccessObjectService(dbContext);

            var coll = dao.GetAllSalaries();

            Assert.Equal(2, coll.Count);

            dao.DeleteSalary(1);

            coll = dao.GetAllSalaries();
            Assert.Single(coll);
            Assert.Equal(2, coll[0].SalaryId);
        }