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Analyzers

Mockolate ships with some Roslyn analyzers to help you adopt best practices and catch issues early, at compile time. All rules provide actionable messages and link to identifiers for easy filtering.

Mockolate0001​

Verify methods only return a VerificationResult and do not directly throw. You have to specify how often you expect the call to happen, e.g. .AtLeastOnce(), .Exactly(n), etc. or use the verification result in any other way.

Example:

IChocolateDispenser sut = IChocolateDispenser.CreateMock();
sut.Dispense("Dark", 1);
// Analyzer Mockolate0001: Add a count assertion like .AtLeastOnce() or use the result.
sut.Mock.Verify.Dispense(It.Is("Dark"), It.IsAny<int>());

The included code fixer suggests to add the .AtLeastOnce() count assertion:

sut.Mock.Verify.Dispense(It.Is("Dark"), It.IsAny<int>()).AtLeastOnce();

Mockolate0002​

Mocked types must be mockable. This rule will prevent you from using unsupported types:

  • CreateMock()
    Type must be an interface, a delegate or a supported class (e.g. not sealed)
  • Implementing<T>()
    Type must be an interface

Mockolate0003​

.Wrap() arguments must be wrappable. The wrapped type must satisfy the same mockability rules as the primary mock target (interface, delegate, or non-sealed class).

Mockolate0004​

Ref-struct parameter mocking is not supported on this compilation. This warning fires when the signature of a mocked member routes through the ref-struct pipeline but the current build environment can't emit the setup surface:

  • Compilation target is older than .NET 9 — the ref-struct pipeline requires the allows ref struct anti-constraint introduced in C# 13 / .NET 9.
  • Parameter is out, ref, or ref readonly and its type is a non-Span<T> / non-ReadOnlySpan<T> ref struct — the mock can't round-trip the value through IOutParameter<T> / IRefParameter<T> when T is a ref struct.
  • Method returns a non-Span<T> / non-ReadOnlySpan<T> ref struct — currently unsupported.

Span<T> and ReadOnlySpan<T> flow through the existing SpanWrapper / ReadOnlySpanWrapper fallback and are not flagged. Custom ref-struct parameters and indexer keys (both get and set) ARE supported on .NET 9+ compilation targets.

See the Ref Struct Parameters section for the supported surface.