I am aware of the lack of complete EDM function mapping in Effort, it is indeed planned to be fixed.

If you wanted to continue testing the library, you could add additional Edm function support in the following class:
http://effort.codeplex.com/SourceControl/changeset/view/11d013f93a0e#Main%2fSource%2fEffort%2fInternal%2fDbCommandTreeTransformation%2fCanonicalFunctions.cs

Its implementation seems a bit messy, so I will probably redesign it completely.

You can find a complete list of EDM functions here:
http://msdn.microsoft.com/en-us/library/bb738626.aspx

Awesome. Thanks for the quick response. :)

I've been planning to help you out with this project, but it's been difficult to find the time recently. I'll try to take a look at this at some point in the near future.

First of all, I wanted to say that this is awesome tool for unit testing. However, there is some errors what make me confused, such as:

"There is no matching CLR function in MMDB for function Edm.IndexOf."

As I know, the mmdb does not support IndexOf function, also, I downloaded the code you refer to. But forgive my knowledge, I do not know the way how to add addtional Edm.IndexOf function. I will appreciate that if you can give me a hand, thanks in advance.

A contributor has been working on this (along with other things) for a while, you can check his implementation at his fork repository:

http://effort.codeplex.com/SourceControl/changeset/8acb420d2571#Main%2fSource%2fEffort%2fInternal%2fDbCommandTreeTransformation%2fCanonicalFunctions.cs