Use this to write a unit test that asserts that your XAML correctly binds to your ViewModel.

AssertNoBindingErrorsTraceListener.cs

class AssertNoBindingErrorsTraceListener : TraceListener
{
    readonly StringBuilder messageBuilder = new StringBuilder();


    public AssertNoBindingErrorsTraceListener(SourceLevels level)
    {
        PresentationTraceSources.DataBindingSource.Listeners.Add(this);
        PresentationTraceSources.DataBindingSource.Switch.Level = level;
    }

    public static IDisposable Start(SourceLevels level = SourceLevels.Warning)
    {
        var listener = new AssertNoBindingErrorsTraceListener(level);
        return new DisposableToken(listener);
    }

    class DisposableToken : IDisposable
    {
        private readonly AssertNoBindingErrorsTraceListener _listener;

        public DisposableToken(AssertNoBindingErrorsTraceListener listener)
        {
            _listener = listener;
        }

        public void Dispose()
        {
            string message = this._listener.messageBuilder.ToString();

            Assert.True(string.IsNullOrEmpty(message), message);
            this._listener.Flush();
            this._listener.Close();
            PresentationTraceSources.DataBindingSource.Listeners.Remove(this._listener);
        }
    }

    public override void Write(string message)
    {
        messageBuilder.Append(message);
    }

    public override void WriteLine(string message)
    {
        messageBuilder.Append(message);
    }
}

WpfAssert.cs

using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using Xunit;

// Requires
// HKCU\Software\Microsoft\Tracing\WPF
//      ManagedTracing = (DWORD) 1
//
// TODO: Fail if that key is not set

static class WpfAssert
{
    /// <summary>
    /// Assert that the UserControl successfully binds to the given ViewModel
    /// </summary>
    public static void BindsSuccessfully(UserControl userControl, object viewModel)
    {
        var hostWindow = new Window { Content = userControl };
        BindsSuccessfully(hostWindow, viewModel);
    }

    /// <summary>
    /// Assert that the Window successfully binds to the given ViewModel
    /// </summary>
    public static void BindsSuccessfully(Window window, object viewModel)
    {
        using (AssertNoBindingErrorsTraceListener.Start())
        {
            window.DataContext = viewModel;

            window.Show(); // force binding
        }
    }
}

WpfAssertTests.cs

public class WpfAssertTests
{
    class TestViewModel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged = delegate { };

        public const string MyPropertyPropertyName = "MyProperty";
        string _myProperty;
        public string MyProperty
        {
            get { return this._myProperty; }
            set
            {
                this._myProperty = value;
                RaisePropertyChanged();
            }
        }

        void RaisePropertyChanged([CallerMemberName]string propertyName = null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    [Fact]
    public void Fail()
    {
        var viewModel = new TestViewModel();
        Binding myBinding = new Binding(TestViewModel.MyPropertyPropertyName + "BOGUS") { Source = viewModel };

        Assert.Throws<Xunit.Sdk.TrueException>(() =>
        {
            using (AssertNoBindingErrorsTraceListener.Start())
            {
                var textBox = new TextBox();
                textBox.SetBinding(TextBlock.TextProperty, myBinding);
            }
        });
    }
}