Project Euler Problem 2

In my last post I talked about how I've been using the Project Euler problems as a sort of Code Kata.  Thanks to @rickasaurus and @calvinb for providing great feedback/comments on that solution!

Problem 2 is below:

Problem 2: "Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be: 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...  Find the sum of all the even-valued terms in the sequence which do not exceed four million." (Project Euler Problem #2)

Tests:

module Problem2Tests

open NUnit.Framework   
  
[<TestFixture>]    
type Problem2__When_finding_sum_of_even_valued_terms_in_the_fibonacci_sequence_up_to_89 () =   
    [<Test>]  
    member this.should_return_sum_of_44 () =  
        let result = Problem2.FindSum 89  
        Assert.AreEqual(44, result)        

[<TestFixture>]    
type Problem2__When_finding_sum_of_even_valued_terms_in_the_fibonacci_sequence_below_4_million () =   
    [<Test>]  
    member this.should_return_sum_of_4613732 () =  
        let result = Problem2.FindSum 4000000  
        Assert.AreEqual(4613732, result)

Code:

module Problem2

let FindSum max =
    let rec getFibonacciSumForEvens lastValue currentValue accumulator =
        match lastValue + currentValue with
        | sum when sum >= max -> accumulator
        | sum when sum % 2 = 0 -> 
            getFibonacciSumForEvens currentValue sum (accumulator + sum)
        | sum -> getFibonacciSumForEvens currentValue sum accumulator
    getFibonacciSumForEvens 0 1 0