在dut方法中使用的模擬lambda表達式
[英]mocking lambda expressions that are used in methods of the dut
問題描述
我有一個下面要進行單元測試的方法：
public string GetReferentie(string prefix)
{
IRepositoryAsync<ParameterGetal> parameterGetalRepository = _unitOfWork.RepositoryAsync<ParameterGetal>();
var dateparameterGetal = parameterGetalRepository
.Query(o => o.parameter=="Datum")
.Select()
.Single();
var ordertellerparametergetal = parameterGetalRepository
.Query(o => o.parameter == "orderteller")
.Select()
.Single();
DateTime date = DateTime.Parse(dateparameterGetal.parameterwaarde);
int orderteller=0;
if (date == DateTime.Today)
{
orderteller = int.Parse(ordertellerparametergetal.parameterwaarde);
}
else
{
dateparameterGetal.parameterwaarde = string.Format("{0:dd/MM/yyyy}", DateTime.Today);
orderteller = 0;
}
orderteller++;
ordertellerparametergetal.parameterwaarde = orderteller.ToString();
string result = string.Format("{0}{1:yyyyMMdd}.{2:00}",prefix,DateTime.Today,orderteller);
return result;
}
這里的問題是，我正在使用2個lambda表達式，這使模擬變得很困難，因為我在stackoverflow中找到的大多數解決方案都制定了基於忽略正在使用的lambda的解決方案。
您如何處理？ 注意，我有解決方案。 接下來，我將其發布為答案。
1 個解決方案
解決方案1
0 已采納 2017-01-26 19:50:56
有時對於單元測試，必須在DUT的設計中務實，並且可能在類中添加僅用於單元測試的內容。 我從上面修改了該類，以使lambda表達式可變，並允許通過getter訪問這些表達式。 這樣，單元測試可以訪問getter，因此模擬程序可以真正檢查要傳遞的lambda。 這里有足夠的談話是代碼：
public class ReferentieBuilder : IReferentieBuilder
{
private readonly IUnitOfWorkAsync _unitOfWork;
private static readonly Expression<Func<ParameterGetal, bool>> _datumExpression = o => o.parameter=="Datum";
private static readonly Expression<Func<ParameterGetal, bool>> _ordertellerExpression = o => o.parameter == "orderteller";
public ReferentieBuilder(IUnitOfWorkAsync unitOfWork)
{
if (unitOfWork == null)
{
throw new ArgumentNullException("unitOfWork");
}
_unitOfWork = unitOfWork;
}
public static Expression<Func<ParameterGetal, bool>> DatumExpression
{
get { return _datumExpression;}
}
public static Expression<Func<ParameterGetal, bool>> OrderTellerExpression
{
get { return _ordertellerExpression; }
}
public string GetReferentie(string prefix)
{
IRepositoryAsync<ParameterGetal> parameterGetalRepository = _unitOfWork.RepositoryAsync<ParameterGetal>();
Debug.Assert(parameterGetalRepository!=null);
var dateparameterGetal = parameterGetalRepository
.Query(DatumExpression)
.Select()
.Single();
var ordertellerparametergetal = parameterGetalRepository
.Query(OrderTellerExpression)
.Select()
.Single();
DateTime date = DateTime.Parse(dateparameterGetal.parameterwaarde);
int orderteller=0;
if (date == DateTime.Today)
{
orderteller = int.Parse(ordertellerparametergetal.parameterwaarde);
}
else
{
dateparameterGetal.parameterwaarde = string.Format("{0:dd/MM/yyyy}", DateTime.Today);
orderteller = 0;
}
orderteller++;
ordertellerparametergetal.parameterwaarde = orderteller.ToString();
string result = string.Format("{0}{1:yyyyMMdd}.{2:00}",prefix,DateTime.Today,orderteller);
return result;
}
}
請參見我已經偽裝了兩個靜態只讀成員變量，並預見了靜態只讀屬性。 DatumExpression和OrderTellerExpression。
單元測試代碼將變成這樣：
[TestFixture]
class ReferentieBuilderTests
{
private IUnitOfWorkAsync _unitOfWork;
[SetUp]
public void setup()
{
List<ParameterGetal> dateParameterGetallen = new List<ParameterGetal>
{
new ParameterGetal{ID = 29, parameter = "Datum", parameterwaarde = string.Format("{0:dd/MM/yyyy}", DateTime.Today.AddDays(-1)) }
};
List<ParameterGetal> tellerParameterGetallen = new List<ParameterGetal>
{
new ParameterGetal{ID = 3, parameter = "orderteller", parameterwaarde = "4" }
};
IQueryFluent<ParameterGetal> datefluent = MockRepository.GenerateStub<IQueryFluent<ParameterGetal>>();
IQueryFluent<ParameterGetal> tellerfluent = MockRepository.GenerateStub<IQueryFluent<ParameterGetal>>();
IRepositoryAsync<ParameterGetal> parametergetalrepository = MockRepository.GenerateStub<IRepositoryAsync<ParameterGetal>>();
_unitOfWork = MockRepository.GenerateStub<IUnitOfWorkAsync>();
_unitOfWork.Stub(u => u.RepositoryAsync<ParameterGetal>())
.Return(parametergetalrepository);
parametergetalrepository.Stub(r => r.Query(ReferentieBuilder.DatumExpression))
.Return(datefluent);
parametergetalrepository.Stub(r => r.Query(ReferentieBuilder.OrderTellerExpression))
.Return(tellerfluent);
datefluent.Stub(q => q.Select())
.Return(dateParameterGetallen);
tellerfluent.Stub(q => q.Select())
.Return(tellerParameterGetallen);
}
[Test]
public void GetFirstReferentieOfDay_returnsCorrectReferentie()
{
ReferentieBuilder referentieBuilder = new ReferentieBuilder(_unitOfWork);
string prefix = "P";
DateTime today = DateTime.Today;
string correctReferentie = string.Format("{0}{1:yyyyMMdd}.01", prefix, today);
Assert.AreEqual(correctReferentie,referentieBuilder.GetReferentie(prefix), "Wrong First Referentie");
}
[Test]
public void GetSecondReferentieOfDay_returnsCorrectReferentie()
{
ReferentieBuilder referentieBuilder = new ReferentieBuilder(_unitOfWork);
string prefix = "P";
referentieBuilder.GetReferentie(prefix);
DateTime today = DateTime.Today;
string correctReferentie = string.Format("{0}{1:yyyyMMdd}.02", prefix, today);
Assert.AreEqual(correctReferentie,referentieBuilder.GetReferentie(prefix), "Wrong Second Referentie");
}
[Test]
public void GetThirdReferentieOfDay_returnsCorrectReferentie()
{
ReferentieBuilder referentieBuilder = new ReferentieBuilder(_unitOfWork);
string prefix = "P";
referentieBuilder.GetReferentie(prefix);
referentieBuilder.GetReferentie(prefix);
DateTime today = DateTime.Today;
string correctReferentie = string.Format("{0}{1:yyyyMMdd}.03", prefix, today);
Assert.AreEqual(correctReferentie, referentieBuilder.GetReferentie(prefix), "Wrong Second Referentie");
}
}
這里的竅門是，該模擬使用的是ReferentieBuilder.DatumExpression和ReferentieBuilder.OrderTellerExpression，而不是在單元測試中以硬編碼方式傳遞相同的lambda表達式。 這具有不重復的額外優點。 通過為允許單元測試訪問的lambda表達式添加只讀屬性，代碼並沒有那么復雜。
請不要過多地判斷代碼的邏輯。 它正在嘗試生成一個從每天1開始的運行編號。 上次訪問該函數的時間以及最后一個數字也存儲在數據庫中。 這是根據要求，我也不喜歡。
也可以使用Eugene注釋以下解決方案：
[TestFixture]
class ReferentieBuilderTests
{
private IUnitOfWorkAsync _unitOfWork;
[SetUp]
public void setup()
{
List<ParameterGetal> dateParameterGetallen = new List<ParameterGetal>
{
new ParameterGetal{ID = 29, parameter = "Datum", parameterwaarde = string.Format("{0:dd/MM/yyyy}", DateTime.Today.AddDays(-1)) }
};
List<ParameterGetal> tellerParameterGetallen = new List<ParameterGetal>
{
new ParameterGetal{ID = 3, parameter = "orderteller", parameterwaarde = "4" }
};
IQueryFluent<ParameterGetal> datefluent = MockRepository.GenerateStub<IQueryFluent<ParameterGetal>>();
IQueryFluent<ParameterGetal> tellerfluent = MockRepository.GenerateStub<IQueryFluent<ParameterGetal>>();
IRepositoryAsync<ParameterGetal> parametergetalrepository = MockRepository.GenerateStub<IRepositoryAsync<ParameterGetal>>();
_unitOfWork = MockRepository.GenerateStub<IUnitOfWorkAsync>();
_unitOfWork.Stub(u => u.RepositoryAsync<ParameterGetal>())
.Return(parametergetalrepository);
parametergetalrepository.Stub(r => r.Query(Arg<Expression<Func<ParameterGetal, bool>>>.Matches(a => LambdaCompare.Eq(a, o => o.parameter == "Datum"))))
.Return(datefluent);
parametergetalrepository.Stub(r => r.Query(Arg<Expression<Func<ParameterGetal, bool>>>.Matches(a => LambdaCompare.Eq(a, o => o.parameter == "orderteller"))))
.Return(tellerfluent);
datefluent.Stub(q => q.Select())
.Return(dateParameterGetallen);
tellerfluent.Stub(q => q.Select())
.Return(tellerParameterGetallen);
}
[Test]
public void GetFirstReferentieOfDay_returnsCorrectReferentie()
{
ReferentieBuilder referentieBuilder = new ReferentieBuilder(_unitOfWork);
string prefix = "P";
DateTime today = DateTime.Today;
string correctReferentie = string.Format("{0}{1:yyyyMMdd}.01", prefix, today);
Assert.AreEqual(correctReferentie,referentieBuilder.GetReferentie(prefix), "Wrong First Referentie");
}
[Test]
public void GetSecondReferentieOfDay_returnsCorrectReferentie()
{
ReferentieBuilder referentieBuilder = new ReferentieBuilder(_unitOfWork);
string prefix = "P";
referentieBuilder.GetReferentie(prefix);
DateTime today = DateTime.Today;
string correctReferentie = string.Format("{0}{1:yyyyMMdd}.02", prefix, today);
Assert.AreEqual(correctReferentie,referentieBuilder.GetReferentie(prefix), "Wrong Second Referentie");
}
[Test]
public void GetThirdReferentieOfDay_returnsCorrectReferentie()
{
ReferentieBuilder referentieBuilder = new ReferentieBuilder(_unitOfWork);
string prefix = "P";
referentieBuilder.GetReferentie(prefix);
referentieBuilder.GetReferentie(prefix);
DateTime today = DateTime.Today;
string correctReferentie = string.Format("{0}{1:yyyyMMdd}.03", prefix, today);
Assert.AreEqual(correctReferentie, referentieBuilder.GetReferentie(prefix), "Wrong Second Referentie");
}
}
可以在這里找到lambda表達式比較器： 測試lambda表達式相等性的最有效方法
使用鏈接的更新。 使用此解決方案，無需在DUT上進行任何更新，即，無需表達式只讀屬性。
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