public void GetAll_via_context()
        {
            var expectedContactsQueryable = MockHelper.ContactTestCollection;
            var mockContactTestCollection = MockHelper.CreateMockDbSet(expectedContactsQueryable);

            var contactServiceMock = new Mock <IContactService>();

            contactServiceMock.Setup(c => c.GetAll()).Returns(mockContactTestCollection.Object);

            var actualContacts   = contactServiceMock.Object.GetAll().ToList();
            var expectedContacts = expectedContactsQueryable.ToList();

            Assert.IsTrue(actualContacts.Count == expectedContacts.Count);
            CollectionAssert.AreEqual(actualContacts, expectedContacts);
        }