如何比较.NET中的两个列表

Question

List<Employee> emplist = new List<Employee>();
emplist.Add(new Employee { Name = "Emp_1", BasicSalary = 1000, Id = Guid.NewGuid(), HRA = 100, DA = 10, TotalSalary = 1110 });
emplist.Add(new Employee { Name = "Emp_2", BasicSalary = 1000 * 2, Id = Guid.NewGuid(), HRA = 200, DA = 20, TotalSalary = 2220 });
emplist.Add(new Employee { Name = "Emp_3", BasicSalary = 1000 * 3, Id = Guid.NewGuid(), HRA = 300, DA = 30, TotalSalary = 3330 });

var result = empRep.CallSupportFindAll();

// CollectionAssert.AreEqual(emplist, result);
Assert.AreEqual(emplist, result);
var r1 = result[0];
Assert.AreEqual(r1.Name, emplist[0].Name);
Assert.AreEqual(r1.TotalSalary, emplist[0].TotalSalary);
Assert.AreEqual(r1.BasicSalary, emplist[0].BasicSalary);

I want to compare two lists emplist and result . Assert.AreEqual(r1.Name, emplist[0].Name); worked but if we have thousands of records then I need to write thousands of lines. so please answer-- for one line code for compare two list... thanks in advance

Answer 1

If I understand correctly, you simply have two instances of List<Employee> and you want to assert that they are equal. Ie they have the same number of Employee instances, in the same order, with equal properties.

If so, this has nothing to do with FakeItEasy. You simply need a method of performing the assertion. Personally I would do this using Fluent Assertions .

result.Should().BeEquivalentTo(emplist);

Answer 2

You can use HashSet<> to compare the two lists.

First, define an equaliser like this

public class EmployeeComparer : IEqualityComparer<Employee>
    {
        public bool Equals(Employee x, Employee y)
        {
            if (x == null && y == null)
                return true;
            if (x == null || y == null)
                return false;

            //You can implement the equal method as you like. For instance, you may compare by name 
            if (x.Id == y.Id)
                return true;
            return false;
        }

        public int GetHashCode(Employee employee)
        {
            return employee.Id.GetHashCode();
        }
    }

Next, create 2 hash sets based on the input and the result of the method

var equaliser = new EmployeeComparer();
HashSet<Employee> inputHashset = new HashSet<Employee>(emplist ,equaliser );
  HashSet<Employee> resultHashset = new HashSet<Employee>(result,equaliser);

Finally, assert the equality of the two sets. It means, instead of

 Assert.AreEqual(emplist, result);

Do

 Assert.IsTrue(inputHashset.SetEquals(resultHashset));

Answer 3

  public bool compareTwolist<T>(List<T> lst1,List<T> lst2)
    {

        bool bresult = false;
        if (lst1.GetType() != lst2.GetType())
        {
            return false;
        }

        //if any of the list is null, return false
        if ((lst1 == null && lst2 != null) || (lst2 == null && lst1 != null))
            return false;

        //if count don't match between 2 lists, then return false
        if(lst1.Count != lst2.Count)
            return false;

       foreach (T item in lst1)
       {
           T obj1 = item;
           T obj2 = lst2.ElementAt(lst1.IndexOf(item));
           Type type = typeof(T);

           foreach (System.Reflection.PropertyInfo property in type.GetProperties())
           {
               string obj1Value = string.Empty;
               string obj2Value = string.Empty;

               if (type.GetProperty(property.Name).GetValue(obj1) != null)
                   obj1Value = type.GetProperty(property.Name).GetValue(obj1).ToString();

               if (type.GetProperty(property.Name).GetValue(obj2) != null)
                   obj2Value = type.GetProperty(property.Name).GetValue(obj2).ToString();

               //if any of the property value inside an object in the list didnt match, return false
               if (obj1Value.Trim() != obj2Value.Trim())
               {
                   bresult = false;
                   break;
               }
           }

       }
         return bresult;

 }

yes, I got a solution by creating user define function and pass two lists which we want to compare..

and just check is var a is true or not

var a = compareTwolist(empwithoutid, resultwithoutid); Assert.IsTrue(a);

Answer 4

The comparison methods suggested in the other answers require you to implement equals on all your objects. This doesn't scale well from a maintenance perspective. Also in some tests only subset of fields are to be compared. This means multiple compare or equals methods to be implemented. An alternative is stateprinter which dumps state to a string to compare against. It can even write and rewrite your asserts for you. See https://github.com/kbilsted/StatePrinter/blob/master/doc/AutomatingUnitTesting.md for more info on automation and https://github.com/kbilsted/StatePrinter/blob/master/doc/TheProblemsWithTraditionalUnitTesting.md for an in depth discussion on problems with unit testing as you are facing now.