learning Unit Tests / nUnit (in C#, msvs2005) - C# Discussion Boards

17-Aug-08 0:54

This site is very useful about Regular Expression .
http://www.regular-expressions.info/[^]
Did you see it ?

Re: Regex

Angelinna17-Aug-08 17:36

Angelinna

17-Aug-08 17:36

Yes I did. Thank you very much for the guidance.

Re: Regex

Mohammad Dayyan18-Aug-08 2:26

How to determine DataGridView column datatype

18-Aug-08 2:26

You're welcome Smile | :)

baranils15-Aug-08 21:08

baranils

15-Aug-08 21:08

Hello

Is it possible to test a datagridview column to know if it is numeric ?

I see nothing, but it must be something because when entering text in a numeric column I get an exception !

Warning : My need is not to handle the exception but to know wich column are numeric in order to set the alignemeent !

Many thanks for any help !

Re: How to determine DataGridView column datatype

dan!sh 15-Aug-08 23:13

dan!sh

15-Aug-08 23:13

If you are usimg a DataTable to fill the GridView, then you can get the column metadata in separate datatable. This table holds the datatype for each column. I am unable to recall the function now, but it was something like GetSchema.

Hope it helps

Re: How to determine DataGridView column datatype

baranils15-Aug-08 23:18

baranils

15-Aug-08 23:18

Thank you

But I finaly found a better way

It is to use the "ValueType" property

for (int i = 0; i < dgv_ScanStat.ColumnCount; i++)
{
  System.Type Tp = dgv_ScanStat.Columns[i].ValueType;
  bool isNumeric =
      Tp == typeof(byte) ||
      Tp == typeof(System.Int16) ||
      Tp == typeof(System.Int32) ||
      Tp == typeof(System.Int64) ||
      Tp == typeof(sbyte) ||
      Tp == typeof(System.UInt16) ||
      Tp == typeof(System.UInt32) ||
      Tp == typeof(System.UInt64) ||
      Tp == typeof(float) ||
      Tp == typeof(double) ||
      Tp == typeof(decimal);

  if (isNumeric)
  {
    dgv_ScanStat.Columns[i].DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight;
  }
}

learning Unit Tests / nUnit (in C#, msvs2005)

noway00115-Aug-08 16:59

noway001

15-Aug-08 16:59

Hi,
I need to learn how to do unit tests for certain functions. I have googled and come accross some stuff, but all the examples are easy.
I read multiple articles on code project, but it didn't help. Usually, I see examples of unit testings functions that take in 1-2 parameters and perform addition/multiplication/etc.
I need to know how to unit test functions that return nothing, take in no parameters, and so on. For example, how do I write unit tests for a function that simply executes a SQL stored procedure? Or a function that just calls other functions?
For example:

private static void DoStuff()
{
  int x = 0, y = 0, z = 0;

  Function1();
  x = Function2();
  if(x > y)
    Function3();
}

Or something like:

private static void ExecProc(int vidID)
{
  try
  {
    SqlCommand cmd  = new SqlCommand("blah", conn);
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.Add(new SqlParameter("@vidID", vidID));
    cmd.ExecuteNonQuery();
  }
  catch (Exception e)
  {
    Console.WriteLine("error: " + e.ToString());
  }
}

I know how to do unit tests for the simple examples, where functions take in a parameter or two, and give some output in certain cases. However, when there is no output, when there is no input, when they talk to the DB or execute stored procs...what are proper unit tests?

I am using Visual Studio 2005 (C#) and have access to nUnit. Ideally, I'd like to learn how to write unit tests (manually) for the above examples, and then learn to use nUnit.

Any help you can provide is appreciated. Also, any links my googling didn't turn up would be appreciated as well. I'm really lost, and am sick of finding the same example that uses functions performing simple arithmetic.
Thanks!

Re: learning Unit Tests / nUnit (in C#, msvs2005)

N a v a n e e t h15-Aug-08 17:45

N a v a n e e t h

15-Aug-08 17:45

You don't test private methods normally. DoStuff() method is hard to test as it has dependencies with other methods. You can use Interaction testing[^] to test DoStuff() method. You should refactor the dependencies to separate classes and just test it calls the expected methods. You have to use mock objects to do this. I suggest you to look at RhinoMocks, a mocking framework.

In the ExecProc() methods you have used ADO.NET classes which is hard to test. So you need to abstract it behind and interface, mock the interface while testing. Check the following,

class ProcedureExecution
{
     IDataAccess dataAccess;
     public ProcedureExecution(IDataAccess dataAccess)
     {
         this.dataAccess = dataAccess;
     }

     public void ExecProc(int vidID)
     {
          try
          {
              dataAccess.Execute("blah",vidID);
          }
          catch (Exception e)
          {
              //Console.WriteLine("error: " + e.ToString());
          }
     }
}

We have abstracted the SQL execution code behind an interface named IDataAccess and we supply it through constructor. It is called dependency injection. While testing you can easily mock IDataAccess. AFAIK, there is no testing required for the above said method as there is nothing to test. Also using static will make testing tough.

If the shown code is your data layer code, then test your method itself and check the values in the database. It's tedious, but it drives out of bugs.

All C# applications should call Application.Quit(); in the beginning to avoid any .NET problems.- Unclyclopedia

How to use google | Ask smart questions

Re: learning Unit Tests / nUnit (in C#, msvs2005)

noway00117-Aug-08 10:02

noway001

17-Aug-08 10:02

Thanks for your help.
I think I'm on the right track now.
I suppose I can do something similar for testing calls to a web service?

I have to read about Interaction testing, and look into RhinoMocks.

Web Browser Navigation Help

ekimfeenux15-Aug-08 14:10

ekimfeenux

15-Aug-08 14:10

I have been making my own web browser in C# and something that isn't necessarily bad is always having to click my 'GO' button. I have gotten used to being able to just hit the 'ENTER' key and be on my way to the web site. I am fairly new to c# coding so I am thinking I am missing a solution somewhere. Any help would be appreciated.

Clipboard Exception ?

Mohammad Dayyan15-Aug-08 13:22

15-Aug-08 13:22

Hi guys.
I try to save and get data from clipboard but this exception occur

Object reference not set to an instance of an object

This is my snippet code.

XElement data = (from node in X_Element.Descendants(nodeName)
                 select node).First();
Clipboard.Clear();
Clipboard.SetData("XElement", data);
XElement newXmlNode = (XElement)Clipboard.GetData("XElement");
MessageBox.Show(newXmlNode.Name.ToString());

I'm sure that there is a XElement data in data

What's wrong with it?
Thanks in advance

Paul Conrad15-Aug-08 13:27

Paul Conrad

15-Aug-08 13:27

Mohammad Dayyan wrote:
Object reference not set to an instance of an object

That generally means there is a missing new....

"The clue train passed his station without stopping." - John Simmons / outlaw programmer

"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon

Mohammad Dayyan15-Aug-08 13:31

15-Aug-08 13:31

But I'm sure that there is a data in it Confused | :confused:

Paul Conrad15-Aug-08 13:34

Paul Conrad

15-Aug-08 13:34

Mohammad Dayyan wrote:
I'm sure that there is a data in it

Are you 100% absolutely sure?

You can't assume that it is always going to put data in there. Common practice in my shop is to declare the object and instantiate it with the new, then try to populate with the data. It does save from a lot of headache.

"The clue train passed his station without stopping." - John Simmons / outlaw programmer

"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon

JoeRip15-Aug-08 13:42

15-Aug-08 13:42

Are you looking at this in the debugger? Which line throws the exception?

If you can't look at it in the debugger for some reason, wrap each line in a try/catch and figure out which line is throwing the exception.

Mohammad Dayyan16-Aug-08 2:18

How thread safe are static fields?

16-Aug-08 2:18

Thanks for reply

JoeRip wrote:
Which line throws the exception?

this line :

XElement newXmlNode = (XElement)Clipboard.GetData("XElement");

JoeRip15-Aug-08 12:47

15-Aug-08 12:47

In the following struct:

public struct myStruct
     {
         public static int CumulativeCountOfInstances;

         public myStruct(int SomeUnusedData)
         {
             CumulativeCountOfInstances++;
         }
     }

If concurrent processes are creating myStruct structs, what prevents collisions as each instance tries to increment CumulativeCountOfInstances?

Mark Salsbery15-Aug-08 12:53

Mark Salsbery

15-Aug-08 12:53

Nothing prevents it.

Maybe a good place for an interlocked increment Smile | :)

How are different processes sharing the same variable?
Or did you mean concurrent threads?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

JoeRip15-Aug-08 12:56

15-Aug-08 12:56

I definitely mean concurrent threads. Friday afternoons are very hard on my concentration.

So I should use Interlocked increments from my constructor, AND I should should use Interlocked exchange any time I want to read this value?

Dang, static isn't as static as I thought it was Smile | :)

Mark Salsbery15-Aug-08 13:29

Mark Salsbery

15-Aug-08 13:29

If you use Interlocked.Increment() / Interlocked.Decrement()
then the new value will be returned (an increment and a read
are combined in one atomic operation).

Reading (for integer types) is atomic (except for 64-bit integers
on a 32-bit processor) so there's no Interlocked.Read except for
longs.

You could use Interlocked.Exchange() if that's what you need to do,
but it's not appropriate for just reading the value (what value would
you exchange?).

To write/modify the variable beyond the atomic operations provided by the
Interlocked class, you'll need to use some other type critical section,
like lock.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

JoeRip15-Aug-08 13:47

Do I still need to LOCK a Synchronized Queue?

15-Aug-08 13:47

Thanks again. I wondered why there was no Read for Int32.

JoeRip15-Aug-08 11:51

Re: Do I still need to LOCK a Synchronized Queue?

15-Aug-08 11:51

if I do this:

Queue SynchedMessageQueue = Queue.Synchronized(new Queue());

then when I access SynchedMessageQueue, do I still need to use LOCK statements?

Or is that now being handled automatically?

Wendelius15-Aug-08 12:30

Wendelius

15-Aug-08 12:30

I believe that this answers the question (from MSDN Queue.Synchronized Method[^]):

To guarantee the thread safety of the Queue, all operations must be done through this wrapper only.

Enumerating through a collection is intrinsically not a thread-safe procedure. 
Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception.
To guarantee thread safety during enumeration, 
you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.

Mika

Re: Do I still need to LOCK a Synchronized Queue?

JoeRip15-Aug-08 12:33