Make It.IsAny, It.IsNotNull work for COM types
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stakx
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Jun 5, 2017
Source/It.cs
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| () => It.IsAny<TValue>()); | ||
| } | ||
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| /// <include file='It.xdoc' path='docs/doc[@for="It.IsNotNull"]/*'/> | ||
| public static TValue IsNotNull<TValue>() | ||
| { | ||
| return Match<TValue>.Create( | ||
| value => value != null && typeof(TValue).IsAssignableFrom(value.GetType()), | ||
| value => value is TValue, |
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The null check can be incorporated into the type check, since null is … is always false.
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Testing a COM object's type using `IsAssignableFrom` can report false negatives. .NET might only see the generic RCW type `__ComObject` in- stead of the COM interface type. The `is` operator on the other hand appears to be performing `QueryInterface` for COM objects to get the right result. Since `is` and `Type.IsAssignableFrom` work somewhat differently (see https://stackoverflow.com/q/44368313/240733), the previous type check is left in place for all objects *except* COM objects; for those, the `is`-based check is used instead. This distinction should reduce the likelihood of introducing a breaking change.
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This fixes #269:
Testing a COM object's type using
IsAssignableFromcan report false negatives because .NET might only see the generic RCW type__ComObjectinstead of the actual COM interface type. Theisoperator on the other hand appears to be performingQueryInterfacefor COM objects to get the right result.This commit introduces an additional branch in
It.IsAny<>that runs anis-based check for COM objects, and the as-is reflection-based check for everything else. The added logic takes effect only in builds targeting the full .NET Framework, since COM is not available on all .NET Core platforms.I have successfully verified the new behaviour against a COM object, but am reluctant to add any permanent test code involving COM to Moq. That would tie the unit test project to a Windows platform-specific facility. (It's possible to work around this by running a test conditionally, depending on the value of
Environment.OSVersion.Platform, but that seems a little hacky.)