title: Cannot assign void to an implicitly-typed variable in unit test
body: <p>everyone, I am trying to write a unit test for my Processor class. in my project, I take a JSON file and Deserialize it and then I build and process it then save it to my database 
  this is my process class</p>
  
  <pre><code>public class CustomerProcessors
      {
          private static IRepository _repository;
          private static PracticeEntities4 _context;
          private static Customer customer;
          public CustomerProcessors()
          {
          }
  
          public CustomerProcessors(IRepository repository)
          {
              _repository = repository;
          }
  
  
          public static void Process(Customer customer)
          {
              var oldcustomer = _repository.GetOldCustomerId(customer.Code.Value);
            if (oldcustomer == null)
              {
                  Save(customer);
              }
              else
                  update(customer);
          }
  
          private static void update(Customer customer)
          {
  
              _repository.UpdateCustomer(customer);
  
          }
  
          private static void Save(Customer customer)
          {
              _repository.SaveCustomer(customer);
          }
      }
  </code></pre>
  
  <p>this is my Builder </p>
  
  <pre><code> public  Customer CustomerBuild(DtoCustomer dto)
          {
              return new Customer()
              {
                  FirstName = dto.FirstName,
                  LastName = dto.LastName,
                  Address = dto.Address,
                  Email = dto.Email,
                  Code = int.Parse(dto.Code),
                  PhoneNumber = dto.Phone
  
              };
          }
  </code></pre>
  
  <p>and finally, this is my unit test </p>
  
  <pre><code>    [TestClass]
     public class CustomerProcessorTest
      {
  
          private static string path;
          private static CustomerDeserializer _customerDeserializer;
          private static CustomerBuilder _customerBuilder;
          private List&lt;Customer&gt; _customers;
          private static Mock&lt;IRepository&gt; mock;
          private  Customer customer;
  
          [ClassInitialize]
          public static void CLassInitialize(TestContext context)
          {
              path = Path.Combine(Environment.CurrentDirectory, @"JSON\", "Customer.json");
          }
  
          [TestInitialize]
          public void TestInitialize()
          {
              mock = new Mock&lt;IRepository&gt;();
              _customerDeserializer = new CustomerDeserializer();
              _customerBuilder = new CustomerBuilder();
              _customers = new List&lt;Customer&gt;();
              Customer customer = new Customer();
          }
  
          [TestMethod]
          public void CusomerDeserialize_customerProcess()
          {
              //Arange
              mock.Setup(e =&gt; e.GetOldCustomerId(1001)).Returns(3);
              mock.Setup(e =&gt; e.GetOldStoreId(200)).Returns(3);
              //Act
              var dtos = CustomerDeserializer.Deserialize(path);
              var dto = dtos.FirstOrDefault(e =&gt; e.Code == "1001");
              var Builder= new CustomerBuilder();
              var customer = Builder.CustomerBuild(dto);
  //Error here
                  var process= CustomerProcessors.Process(customer);
  
              //Asset
              Assert.AreEqual(0, _customers.Count);
          }
  
  
      }
  }
  </code></pre>
  
  <p>I have this error and I don't know what to do?</p>