Question: How to mock a method that passes a parameter by reference? about delphi-mocks HOT 3 OPEN

Currently there isn't a way to achieve var or out parameter return values with Delphi.Mocks. I have had plans on how to achieve this, just haven't had the time to attempt its implementation.

The DoInvoke of the proxy classes needs to handle updating var variables and out variables. Even though the args array is const itself, from memory the values of the variables at each index could be altered to the desired values. These would then be returned to the caller, only when the value was either listed as var, or out. If there is information on the method as to the parameter type we could even protect against this.

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Thanks for the reply. Doesn't sound like any small undertaking to achieve this capability. My best bet would probably be to eliminate my argument passed by reference and have my method just return the data instead; pass the old result value of the method through a separate property/method.

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-----Original Message-----
From: Jason Smith [email protected]
To: VSoftTechnologies/Delphi-Mocks [email protected]
Cc: Ryan Potts [email protected]
Sent: Tue, 29 Mar 2016 7:32 PM
Subject: Re: [VSoftTechnologies/Delphi-Mocks] Question: How to mock a method that passes a parameter by reference? (#88)

Currently there isn't a way to achieve var or out parameter return values with Delphi.Mocks. I have had plans on how to achieve this, just haven't had the time to attempt its implementation.

The DoInvoke of the proxy classes needs to handle updating var variables and out variables. Even though the args array is const itself, from memory the values of the variables at each index could be altered to the desired values. These would then be returned to the caller, only when the value was either listed as var, or out. If there is information on the method as to the parameter type we could even protect against this.

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Reply to this email directly or view it on GitHub:
#88 (comment)

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Yes, and it is one of the draw backs for using Delphi.Mocks. Even in C# you have to do something like the following for Moq.

int outVariable = 2;
myMock.Setup(x => x.FuncWithOutVar(out outVariable)).Returns(true);

The outVariable always gets a hint saying it could be removed as the value is not used. I suspect we would get the same thing in delphi as the compiler has no idea we are intercepting the method call.

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