public void IsAssignable_ReturnsTrueIfAncestorTypeImplementsInterface()
{
// Arrange
var source = @"
namespace TestApp
{
public interface ITestInterface
{
}
public class ITestInterfaceA : ITestInterface
{
}
public class ITestInterfaceB : ITestInterfaceA
{
}
public class TestClass : ITestInterfaceB
{
}";
var compilation = TestCompilation.Create(source);
var sourceType = compilation.GetTypeByMetadataName("TestApp.ITestInterface");
var target = compilation.GetTypeByMetadataName("TestApp.TestClass");
// Act
var isAssignableFrom = CodeAnalysisExtensions.IsAssignableFrom(sourceType, target);
var isAssignableFromDerived = CodeAnalysisExtensions.IsAssignableFrom(target, sourceType);
// Assert
Assert.True(isAssignableFrom);
Assert.False(isAssignableFromDerived); // Inverse shouldn't be true
}
public void IsAssignable_ReturnsTrue_IfSourceAndDestinationAreTheSameInterface()
{
// Arrange
var source = @"
namespace TestApp
{
public interface ITestInterface { }
}";
var compilation = TestCompilation.Create(source);
var sourceType = compilation.GetTypeByMetadataName("TestApp.ITestInterface");
var target = compilation.GetTypeByMetadataName("TestApp.ITestInterface");
// Act
var isAssignableFrom = CodeAnalysisExtensions.IsAssignableFrom(sourceType, target);
// Assert
Assert.True(isAssignableFrom);
}
public void IsAssignable_ReturnsFalseIfTypeDoesNotImplementInterface()
{
// Arrange
var source = @"
namespace TestApp
{
public class TypeA { }
}";
var compilation = TestCompilation.Create(source);
var sourceType = compilation.GetTypeByMetadataName("TestApp.TypeA");
var target = compilation.GetTypeByMetadataName("System.IDisposable");
// Act
var isAssignableFrom = CodeAnalysisExtensions.IsAssignableFrom(sourceType, target);
// Assert
Assert.False(isAssignableFrom);
}
public void IsAssignable_ReturnsTrueIfTypesAreExact()
{
// Arrange
var source = @"
namespace TestApp
{
public class TestType { }
}";
var compilation = TestCompilation.Create(source);
var sourceType = compilation.GetTypeByMetadataName("TestApp.TestType");
var target = compilation.GetTypeByMetadataName("TestApp.TestType");
// Act
var isAssignableFrom = CodeAnalysisExtensions.IsAssignableFrom(sourceType, target);
// Assert
Assert.True(isAssignableFrom);
}
public void IsAssignable_ReturnsFalseForDifferentTypes()
{
// Arrange
var source = @"
namespace TestApp
{
public class TypeA { }
public class TypeB { }
}";
var compilation = TestCompilation.Create(source);
var sourceType = compilation.GetTypeByMetadataName("TestApp.TypeA");
var target = compilation.GetTypeByMetadataName("TestApp.TypeB");
// Act
var isAssignableFrom = CodeAnalysisExtensions.IsAssignableFrom(sourceType, target);
// Assert
Assert.False(isAssignableFrom);
}