Im using Moq to create mocks of a data set.
I have created a little helper class that allows me to have an in memory storage instead of a database that makes unit testing a breeze. That way I can add and remove items from my mock data set, this allows me to test my insert and delete service calls.
During the setup of the mock I have a line that looks like the following
this.Setup(i => i.AcademicCycles).Returns(mockStore.GetList<AcademicCycle>());
My mock has a lot of properties so I would like to perform this setup step using reflection. I have managed to the Returns
part of the process working via reflection but I am stuck on the lambda method to Setup
.
Setup
takes an
Expression<Func<GoalsModelUnitOfWork, IQueryable<AcademicCycle>>>
that corresponds to the i => i.AcademicCycles
and I would like to create this dynamically. Using reflection I have the following:
The name of the property: "AcademicCycles"
The type IQueryable<AcademicCycle>
The type AcademicCycle
I also have the instance of the i
in the lambda statement which is a GoalsModelUnitOfWork
The code to create the expression dynamically would be like this:
ParameterExpression parameter = Expression.Parameter(typeof (GoalsModelUnitOfWork), "i"); MemberExpression property = Expression.Property(parameter, "AcademicCycles"); var queryableType = typeof (IQueryable<>).MakeGenericType(typeof (AcademicCycle)); var delegateType = typeof (Func<,>).MakeGenericType(typeof (GoalsModelUnitOfWork), queryableType); var yourExpression = Expression.Lambda(delegateType, property, parameter);
The result will have the desired type, but the problem is that the return type of Expression.Lambda()
is LambdaExpression
and you can't perform a type cast to Expression<Func<...>>
to pass it as parameter to your setup function because you don't know the generic type parameters for the Func
. So you have to invoke the Setup
method by reflection, too:
this.GetType().GetMethod("Setup", yourExpression.GetType()).Invoke(this, yourExpression);
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