In this recipe, you will also see an example of how to use the Extern reserved object to define references to methods in external DLLs such as those of the Win32 API. These methods can then be loaded and executed during runtime. We have already seen an example of this in the Reading values from an INI file recipe in Chapter 1, Data-driven Tests. Here, we will learn how to implement a function that draws a rectangle on the screen with the color of your choice. This is useful to mark areas on the screen that are of interest (especially when the test fails) and hence, makes the report analysis task more efficient.
From the File menu, navigate to New | Test, or use the Ctrl + N shortcut.
To complete this recipe, we need the global Extern object, which, with proper use, provides UFT with access to the methods of an external Dynamic Link Library (DLL). We will define a variable and assign it a reference to the global Extern object (this is done to avoid persistence, as Extern is a reserved object that is not released from memory until UFT closes):
Dim oExternObj Set oExternObj = Extern
Then, we will declare the methods required to accomplish our task; in this case, to draw a rectangle on the screen:
With oExternObj
.Declare micHwnd, "GetDesktopWindow", "User32.DLL", "GetDesktopWindow"
.Declare micULong, "GetWindowDC", "User32.DLL", "GetWindowDC",micHwnd
.Declare micInteger, "ReleaseDC", "User32.DLL", "ReleaseDC", micHwnd, micULong
.Declare micULong, "CreatePen", "Gdi32.DLL", "CreatePen", micInteger, micInteger, micDword
.Declare micInteger, "SetROP2", "Gdi32.DLL", "SetROP2", micULong, micInteger
.Declare micULong, "SelectObject", "Gdi32.DLL", "SelectObject", micULong, micULong
.Declare micULong, "DeleteObject", "Gdi32.DLL", "DeleteObject", micULong
.Declare micULong, "GetStockObject", "Gdi32.DLL", "GetStockObject", micInteger
.Declare micULong, "Rectangle", "Gdi32.DLL", "Rectangle", micULong, micInteger, micInteger, micInteger, micInteger
End WithAfter we define the connection to the DLL with its returned value and arguments, we will write a function that accepts the following arguments, namely, TestObject and a reference to the Extern object named oExternLocal:
Function DrawRect(ByRef TestObject, ByVal oExternLocal)
Dim YTop, XLeft, YBottom, XRight
Dim hDC, hPen
'Get object coordinates
With TestObject
XLeft = .GetROProperty("abs_x")
YTop = .GetROProperty("abs_y")
YBottom = YTop+.GetROProperty("height")-1
XRight = XLeft+.GetROProperty("width")-1
End With
With oExternLocal
' Get the Desktop DC
hDC = .GetWindowDC(.GetDesktopWindow)
' Create a five pixels wide Pen
hPen = .CreatePen(6, 5, RGB(0, 0, 0)) ' PS_INSIDEFRAME, 3 , RGB(0, 0, 0)
.SetROP2 hDC, 6 ' hDC, R2_NOT
.SelectObject hDC, hPen
' Use an empty fill
.SelectObject hDC, .GetStockObject (5) ' NULL_BRUSH
' Draw the rectangle
.Rectangle hDC, XLeft, YTop, XRight, YBottom
' CleanUp
.ReleaseDC .GetDesktopWindow, hDC
.DeleteObject hPen
End With
Set oExtern = Nothing
End Function To utilize the function, use the following code:
DrawRect Window("Notepad").WinEditor("Edit"), oExternObjAs a result of running the test, the Notepad window would look similar to the following screenshot for a brief time (it is possible to extend it by adding a Wait command before releasing the drawing context and pen objects):
First, we use the variable oExternObj as a reference (shallow copy) to the Extern reserved object to avoid persistence, that is, to ensure that the declared external methods do not remain in memory. Otherwise, we will need to close and reopen UFT to reset the Extern object.
Second, we call the function DrawRect and pass TestObject to be highlighted (in this case, the Notepad WinEditor) and the oExternObj variable.
Third, the function DrawRect calculates the boundaries of the given TestObject, and calls the relevant methods from the external Win32 API via the oExternLocal object to set the required resources (Pen, Drawing Context, and so on). It then uses the Rectangle method to actually draw a five-pixel-wide rectangle around TestObject. Finally, it releases the resources.