Mock Registry.GetValue

[Keith Knight]

I am attempting to mock Registry.GetValue with specific parameters using the following code:

Mock.Arrange(Function() Registry.GetValue("HKEY_CURRENT_USER\Software\VB and VBA Program Settings\Legacy App\Options", "SettingValue", String.Empty)).Returns("Test Result")

I get the following exception:

{"Object reference not set to an instance of an object."}
   at ..( parsed, Type argType, Int32 argIndex, Expression argExpression) in c:\B\Basilisk\Basilisk CI Build\Sources\CodeBase\Telerik.JustMock\DynamicParser.cs:line 114
   at ..Œ(MethodCallExpression expression) in c:\B\Basilisk\Basilisk CI Build\Sources\CodeBase\Telerik.JustMock\DynamicParser.cs:line 94
   at ..ˆ(Expression expression) in c:\B\Basilisk\Basilisk CI Build\Sources\CodeBase\Telerik.JustMock\ExpressionVisitor.cs:line 61
   at ..() in c:\B\Basilisk\Basilisk CI Build\Sources\CodeBase\Telerik.JustMock\DynamicParser.cs:line 34
   at ..(Object obj, Type mockTarget, MethodInfo method, Expression expression) in c:\B\Basilisk\Basilisk CI Build\Sources\CodeBase\Telerik.JustMock\MockContext.cs:line 31
   at ..(Expression`1 expression) in c:\B\Basilisk\Basilisk CI Build\Sources\CodeBase\Telerik.JustMock\MockContext.cs:line 23
   at Telerik.JustMock.Mock...€( x) in c:\B\Basilisk\Basilisk CI Build\Sources\CodeBase\Telerik.JustMock\Mock.cs:line 75
   at ..[TDelgate,TReturn](† instruction, Func2`2 function) in c:\B\Basilisk\Basilisk CI Build\Sources\CodeBase\Telerik.JustMock\MockContext.cs:line 226
   at Telerik.JustMock.Mock.Arrange[TResult](Expression`1 expression) in c:\B\Basilisk\Basilisk CI Build\Sources\CodeBase\Telerik.JustMock\Mock.cs:line 73
   at xxxx.vb

Is there something that I can do differently?

Thanks,
Keith

[Ricky]

Hi Keith,

Thank you for submitting the issue. However, I found that there is an issue with expression parsing for VB when you pass string for object type argument. I have added this to the backlog and hopefully it will be fixed in the next release.

Currently, the workaround for this is to rewrite Mock.Arrange in the following way:

Mock.Arrange(Function() Registry.GetValue(Arg.AnyString, "SettingValue", Arg.AnyObject)).Returns("Test Result")

Here, I have used Arg.AnyObject instead of the original string value. Since, this is an MsCorlib member you also need to have a MockClassAttribute and Initialize it during test setup. I have attached a test project for Registry.GetValue which shows it further.

Additionally, mocking Registry.GetValue works well for test written with NUNit + TestDriven.Net but fails with MsTest where it calls the original method. It seems that MSTest is making call to Registry before running the test and although everthing is setup and injected properly it is calling the original method. Therefore, as of now Registry.GetValue won’t work under MSTest.

With Regards,
Ricky