Question

I am new to Rhino Mocks, and using mock isolation frameworks in general for unit testing. I have written the following test, where I have set up an expectation for a mock IDataProvider object to return a collection of objects. The collection supplied has one object in it.

When I run the test, the call to the IDataProvider returns a empty list when it should return the list with one object in it.

Any ideas whats going wrong?

Here is my test: (Please excuse any bad practises here… feel free to mention any. Im trying to learn! Thanks)

[TestMethod()]
public void FetchDataSeries_NeedsUpdate_SuccessfulDataSeriesRetrievedFromDataProvider() {
  List<IDataSeries> dataSeries = new List<IDataSeries>();
  dataSeries.Add(new DataSeries("test"));
  DrillDownLevel level = DrillDownLevel.YEAR;
  int? year = 2008;

  var dataProvider = _MockRepository.CreateMock<IDataProvider>();
  dataProvider.Expect(dp => dp.GetDataSeries(String.Empty, level, year, null ,null, null)).Return(dataSeries);
  _DataSourceContext.DataProvider = dataProvider;

  CollectionAssert.AreEqual(dataSeries, _DataSourceContext.FetchDataSeries(level, year, null, null, null));
  dataProvider.VerifyAllExpectations();
}

Relevant portion of method under test: (The DataProvider.GetDataSeries call returns empty list… this should return stubbed list.)

      public override List<IDataSeries> FetchDataSeries(DrillDownLevel? drillDownLevel, int? year, int? month, DateTime? week, int? day) {

    List<IDataSeries> dataSeries = new List<IDataSeries>();

    // Cache data for maximum cache period
    // if data has been cached for longer than the maxium cache period OR the updateInterval has elapsed UNLESS LastUpdateAttempt was less than minimum update interval
    if (NeedsUpdate(LastUpdate, LastUpdateAttempt)) {

      // Attempt to get new data
      LoggingService.InfoFormat("DataSourceContext: {0}: Attempting to get new data:", Name);
      dataSeries = DataProvider.GetDataSeries(DataQuery, drillDownLevel, year, month, week, day);
    }

    return dataSeries;
  }

Answer 1

You’re missing a call to ReplayAll:

    _MockRepository.ReplayAll();
    CollectionAssert.AreEqual(dataSeries, _DataSourceContext.FetchDataSeries(level, year, null, null, null));

See: http://ayende.com/Wiki/Comparison+of+different+Rhino+Mocks+syntaxes.ashx