Pex does not support decimal

So not able to do much this weekend I decided to use Pex to do some testing on a project I am busy on.  The class I needed to test was a quote detail line where there is two quantities, of which only one can be specified depending on the property DealerSupplied.  Here is the bare properties:

   1: public decimal DealerQty

   2: {

   3:     get

   4:     {

   5:         return _DealerQty;

   6:     }

   7:     set

   8:     {

   9:         if (!DealerSupplied && value != 0)

  10:         {

  11:             throw new ArgumentException("You cannot set the DealerQty if the product is not DealerSupplied.");

  12:         }

  13:  

  14:         SetPropertyValue("DealerQty", ref _DealerQty, value);

  15:     }

  16: }

  17:  

  18: public bool DealerSupplied

  19: {

  20:     get

  21:     {

  22:         return _DealerSupplied;

  23:     }

  24:     set

  25:     {

  26:         SetPropertyValue("DealerSupplied", ref _DealerSupplied, value);

  27:         if (_DealerSupplied)

  28:         {

  29:             WMSQty = 0;

  30:         }

  31:         else

  32:         {

  33:             DealerQty = 0;

  34:         }

  35:     }

  36: }

  37:  

  38: public decimal WMSQty

  39: {

  40:     get

  41:     {

  42:         return _WMSQty;

  43:     }

  44:     set

  45:     {

  46:         if (DealerSupplied && value != 0)

  47:         {

  48:             throw new ArgumentException("You cannot set the WMSQty if the product is DealerSupplied.");

  49:         }

  50:         SetPropertyValue("WMSQty", ref _WMSQty, value);

  51:     }

  52: }

Initially I was guessing that I’d need at least 6 or 7 tests to test these three properties.

So how can Pex help me explore this code?

Well I thought I’d try the following code:

   1: [PexMethod]

   2: public void DealerSupplied_Qty_Test_Dec(bool dealerSupplied, decimal wmsQty, decimal dealerQty)

   3: {

   4:     StubQuoteComponentBase target = new StubQuoteComponentBase();

   5:     target.DealerSupplied = dealerSupplied;

   6:     target.WMSQty = wmsQty;

   7:     target.DealerQty = dealerQty;

   8: }

I was a bit surprised when I got only two tests back from Pex.  I was even more surprised when I saw the values.

So my first reaction was to shoot of an email to Pex Support.  I then tried to use int’s instead of decimal’s.

   1: [PexMethod]

   2: public void DealerSupplied_Qty_Test_Int(bool dealerSupplied, int wmsQty, int dealerQty)

   3: {

   4:     StubQuoteComponentBase target = new StubQuoteComponentBase();

   5:     target.DealerSupplied = dealerSupplied;

   6:     target.WMSQty = wmsQty;

   7:     target.DealerQty = dealerQty;

   8: }

This gave me a much better result:

Then I got an email from Nikolai, where he confirmed that Pex does not play well with the decimal value type.  In his words: ‘all generated tests are bogus’ when using decimal as parameters.