Question

How do I mock the method GetValues() in System.Data.IDataReader?

This method changes the array of objects passed to it, so it can’t simply return a mocked value.

private void UpdateItemPropertyValuesFromReader( object item, IDataReader reader ) {     object[] fields = new object[ reader.FieldCount ];     reader.GetValues( fields ); //this needs to be mocked to return a fixed set of fields       // process fields    ... } 

Answer 1

you need to use the method Expect.Do() which takes a delegate. this delegate then needs to ‘do’ something, in place of the calling code. Therefore, write a delegate that populates the fields variable for you.

private int SetupFields( object[] fields ) {     fields[ 0 ] = 100;     fields[ 1 ] = 'Hello';     return 2; }  [Test] public void TestGetValues() {     MockRepository mocks = new MockRepository();      using ( mocks.Record() )     {         Expect             .Call( reader.GetValues( null ) )             .IgnoreArguments()             .Do( new Func<object[], int>( SetupField ) )     }          // verify here }