public void CheckIfCompanyNameIsAvailableShouldReturnTrueIfCompanyExist() { var options = new DbContextOptionsBuilder <TaskPlannerDbContext>() .UseInMemoryDatabase(databaseName: "Company_CheckCompanyName_Database") .Options; var dbContext = new TaskPlannerDbContext(options); var company = new Company { Name = "DataCenter", Address = "asd", FieldOfService = "IT" }; dbContext.Companies.Add(company); var companyService = new CompanyService(dbContext, null); var result = companyService.CheckIfCompanyNameIsAvailable(company.Name); Assert.True(result); }