public async Task MergePartialTypeMergesModifiers(string firstModifiers, string secondModifiers,
                                                          InterfaceModifiers expected)
        {
            var firstCode =
                TypeDefinitionCode.EmptyInterface.Replace("interface", firstModifiers + " partial interface");
            var secondCode = TypeDefinitionCode.EmptyInterface
                             .Replace("interface", secondModifiers + " partial interface");

            var firstNode = await TestNode.FindNode <InterfaceDeclarationSyntax>(firstCode)
                            .ConfigureAwait(false);

            var secondNode = await TestNode.FindNode <InterfaceDeclarationSyntax>(secondCode)
                             .ConfigureAwait(false);

            var firstDefinition  = new InterfaceDefinition(firstNode);
            var secondDefinition = new InterfaceDefinition(secondNode);

            firstDefinition.MergePartialType(secondDefinition);

            firstDefinition.Modifiers.Should().Be(expected);
        }