Counterfeit counterfeit in FakeItEasy

Question

How to create a fake with FakeItEasy , which allows you to use different return values ​​for consecutive calls. This is one example of what I would like to do:

var enumerator = A.Fake<IDictionaryEnumerator>();
A.CallTo(() => enumerator.MoveNext()).Returns(true);  //Expected value for first call
A.CallTo(() => enumerator.Key).Returns("key1");
A.CallTo(() => enumerator.Value).Returns("value1");
A.CallTo(() => enumerator.MoveNext()).Returns(false); //Expected value for second call

Assert.IsTrue(enumerator.MoveNext());    //Fails
Assert.IsFalse(enumerator.MoveNext());   

The statement will fail because the last MoveNext setting will overwrite the first.

Is it possible to do what I want in FakeItEasy ?

.

[edit] A
refined source question and a working example below.

Based on Patrik, the answer to this code shows how you can configure the fake. The trick is to cancel all settings and use Once().

var enumerator = A.Fake<IDictionaryEnumerator>();
A.CallTo(() => enumerator.MoveNext()).Returns(false).Once();
A.CallTo(() => enumerator.MoveNext()).Returns(true).NumberOfTimes(2);
A.CallTo(() => enumerator.Key).Returns("key2").Once();
A.CallTo(() => enumerator.Value).Returns("value2").Once();
A.CallTo(() => enumerator.Key).Returns("key1").Once();
A.CallTo(() => enumerator.Value).Returns("value1").Once();

while(enumerator.MoveNext())
{
    Debug.WriteLine(enumerator.Key + ": "+ enumerator.Value);               
}

This will print:

key1: value1
key2: value2

Answer 1

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A.CallTo(() => enumerator.MoveNext()).ReturnsNextFromSequence(false, true);

:

A.CallTo(() => enumerator.MoveNext()).Returns(true);
A.CallTo(() => enumerator.MoveNext()).Returns(false).Once();

Edit:

, , , , , MoveNext true false ? , .

FakeItEasy /, , . repeat - ".Once()" - , .

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Answer 2

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, :

public static void AFakeDictionaryEnumeratorReturns(
                       IDictionaryEnumerator enumerator, params object[] pairs)
{
    if (0 != pairs.Length % 2)
        throw new ArgumentException("pairs must have even number of elements", "pairs");

    int n = pairs.Length / 2;

    A.CallTo(() => enumerator.MoveNext()).Returns(false).Once();
    A.CallTo(() => enumerator.MoveNext()).Returns(true).NumberOfTimes(n);

    for (int i = pairs.Length; i > 0; i -= 2)
    {
        A.CallTo(() => enumerator.Key).Returns(pairs[i - 2]).Once();
        A.CallTo(() => enumerator.Value).Returns(pairs[i - 1]).Once();
    }
}

:

var enumerator = A.Fake<IDictionaryEnumerator>();
AFakeDictionaryEnumeratorReturns(enumerator, 
                                 "key1", "value1", "key2", "value2", "key3", "value3");

var keys = new List<object>();
var values = new List<object>();
while (enumerator.MoveNext())
{
    keys.Add(enumerator.Key);
    values.Add(enumerator.Value);
}

Assert.Equal(new List<object> { "key1", "key2", "key3" }, keys);
Assert.Equal(new List<object> { "value1", "value2", "value3" }, values);

(An IDictionaryEnumerator , , . IEnumerator<T> .)