Have a LINQ query expression (below) that want to test mocking the Entity Framework. To mock I am using the code: Entity Framework Testing with a Mocking Framework This works for other queries but doesn't work for this
var query = from vwPs in _reportingDbContext.VwAccountNumber join ps in _reportingDbContext.PaymentSummary on new { Key1 = vwPs.Id, Key2 = vwPs.AccountNumber, Key3 = true, Key4 = true } equals new { Key1 = ps.Id, Key2 = ps.AccountNumber, Key3 = ps.PaymentDate >= fromDateTime, Key4 = ps.PaymentDate < toDateTime } into viewJoinPayment from ps in viewJoinPayment.DefaultIfEmpty() join prg in generatedReportIds on ps.PaymentRef equals prg into paymentJoinGenerated from prgRow in paymentJoinGenerated.DefaultIfEmpty() where vwPs.Id == Id select new { vwPs.AccountNumber, Payments = ps, ReportGenerated = prgRow }; When execute the query the value in '_inner' at this point in the code
internal class TestDbAsyncEnumerator<T> : IDbAsyncEnumerator<T> { //... public Task<bool> MoveNextAsync(CancellationToken cancellationToken) { return Task.FromResult(_inner.MoveNext()); } //... }
? _inner {System.Linq.Enumerable.WhereSelectEnumerableIterator<<>f__AnonymousType11<<>f__AnonymousType10<<>f__AnonymousType9<<>f__AnonymousType7>, LL.Core.DataAccess.Models.PaymentSummaryEntity>, System.Collections.Generic.IEnumerable>, int>, <>f__AnonymousType12>} Current: null
Results View: Expanding the Results View will enumerate the IEnumerable
and when it executes the MoveNext() get exception
? _inner.MoveNext() '_inner.MoveNext()' threw an exception of type 'System.NullReferenceException' Data: {System.Collections.ListDictionaryInternal} HResult: -2147467261 HelpLink: null InnerException: null Message: "Object reference not set to an instance of an object." Source: "Anonymously Hosted DynamicMethods Assembly" StackTrace: " at lambda_method(Closure , <>f__AnonymousType9
2 )\r\n at System.Linq.Enumerable.<GroupJoinIterator>d__404.MoveNext()\r\n at System.Linq.Enumerable.d__223.MoveNext()\r\n at System.Linq.Enumerable.WhereSelectEnumerableIterator2.MoveNext()" TargetSite: {Int32 lambda_method(System.Runtime.CompilerServices.Closure, <>f__AnonymousType92[<>f__AnonymousType72[LL.Core.DataAccess.Models.VwAccountNumberEnt ity,System.Collections.Generic.IEnumerable`1[LL.Core.DataAccess.Models.PaymentSummaryEntity]],LL.Core.DataAccess.Models.PaymentSummaryEntity])}
Tried few changes including the one suggested in here DbSet mock, no results while calling ToList secondly
but still get the same problem. Please, can anybody give some light?
Verify query implementation with integration tests is not an option, as boss wants this to be tested at unit test level as all the other queries.
UPDATE: Thanks @Eduard Malakhov this is something tried. If remove the both 'DefaultIfEmpty' and run the query it doesn't throw the exception. But how can avoid the exception with the DefaultIfEmpty? How can I modify the mocking code to check this case, as the exception is not happening with a not mocked call?
var query = from vwPs in _charityReportingDbContext.VwCharityAccountNumber join ps in _charityReportingDbContext.PaymentSummary on new { Key1 = vwPs.CharityId, Key2 = vwPs.AccountNumber, Key3 = true, Key4 = true } equals new { Key1 = ps.CharityId, Key2 = ps.AccountNumber, Key3 = ps.PaymentDate >= fromDateTime, Key4 = ps.PaymentDate < toDateTime } into viewJoinPayment select new { vwPs.AccountNumber, };