如何在c＃桌面应用程序中对特定功能执行单元测试？

Question

I have a function named LoadCitation.

public void LoadCitation()
    {

        cmd = new SqlCommand("select * from tbl_Users where isLogin=1", con);
        sqlDataAdapter = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        sqlDataAdapter.Fill(ds);
        String username = ds.Tables[0].Rows[0]["username"].ToString();
        sqlDataAdapter = new SqlDataAdapter("select id,title,author1_fname,author1_lname,author2_fname,author2_lname,author3_fname,author3_lname,doctype,year,publisher,abstract,nameofdoc,issue,volume,pgno,url,accessdate,notes,tag from tbl_Citation  where username ='" + username + "'", con);
        DataSet = new DataSet();
        con.Open();
        sqlDataAdapter.Fill(DataSet, "tbl_Citation");
        con.Close();

        dgeviewcitation.DataSource = DataSet;
        dgeviewcitation.DataMember = "tbl_Citation";
    }

I want to perform unit testing for this method.

[TestClass()]
public class EditcitationTests
{

    [TestMethod()]
    public void LoadCitationTest()
    {

    }
}

I have created method but didn't know what to write inside the function for unit testing...

Answer 1

As written, this method is not unit testable.

That's because it has a hard dependency on an external resource. What if the test was run in an environment that didn't have that DB set up? How do you know what data will be in the DB? Unit tests should never leave their class (and any mocks).

So first, you need to get that SQL into a service that is injected into your form (also fix the SQL injection vulnerability while you're at it!). Then your test will mock that service (using something like NSubstitute or Moq ) and you can verify that the data the mock returns is stored correctly in dgeviewcitation .

Note that UIs are usually terrible candidates for unit tests, the correct approach is to have them as a very thin (as thin as possible) layer over your actual logic, and then unit test the logic. Architectural patterns like MVVM try to help with this.