NewSetup.cs

private TestedObject testedObject;
private IDependency depency;

[SetUp]
public void Setup()
{
  var dependency = new Mock<IDependency>();
  // dependency setup
  testedObject = new TestedObject(depency.object);
}

[Test]
public void It_works_with_dependencies()
{
  var result = testedObject.WorkWithDependency();
  // assert result
  dependency.Verify(d => d.WasNotified());
}