Beginning Unit Testing with NUnit in Visual Studio

How to start with NUnit?

Download it from http://www.nunit.org/ and install it. It should be installed at C:\Program Files (x86)\NUnit 2.6.2. (2.6.2 is the current release version in the time of writing this article)

How to organise my projects? Where to put unit tests?

Put the business logic of your app in a class library project (e.g. MyBusinessLogic.dll). Your main app (MyApp.exe) project references this dll. Put unit tests in a separate project (e.g. MyBusinessLogicTester.dll) but within the same solution. MyBusinessLogicTester.dll will reference nunit.framework.dll (located at C:\Program Files (x86)\NUnit 2.6.2\bin) and MyBusinessLogic.dll.

How to run NUnit tests?

In MyBusinessLogicTester project: go to Properties -> Debug. Set Start external program to C:\Program Files (x86)\NUnit 2.6.2\bin\nunit.exe and put MyBusinessLogicTester.dll in Command line arguments field.

Set MyBusinessLogicTester as a StartUp project in your solution and run it. Nunit GUI app (nunit.exe) will open and display all test fixtures and tests in the left-hand side tree view. You can select tests you want to run and then execute them.

If you're running MyBusinessLogicTester tests with ReSharper, make sure MyBusinessLogicTester is marked to be built in the Configuration Manager.


Links and References:
http://www.nunit.org/
http://stackoverflow.com/questions/67299/is-unit-testing-worth-the-effort
http://stackoverflow.com/questions/1365943/how-to-start-unit-testing-or-tdd
http://stackoverflow.com/questions/347156/do-you-put-unit-tests-in-same-project-or-another-project
http://stackoverflow.com/questions/3979855/how-do-i-set-up-nunit-to-run-my-projects-unit-tests
http://stackoverflow.com/questions/759854/how-do-i-run-nunit-in-debug-mode-from-visual-studio
http://stackoverflow.com/questions/3476054/can-unit-testing-be-successfully-added-into-an-existing-production-project-if-s
http://stackoverflow.com/questions/6103807/unit-testing-philosophy

Hello, world! in NSIS - the simplest NSIS script

NSIS requires two things to be present in a script:

1) call to OutFile function (in order to define installer's name and output directory)
2) at least one Section (NSIS script executes sections and each section can contain functions and instructions; functions contain instructions only)

So, the shortest script that compiles could be:

HelloWorld.nsi:




NSIS compiler creates HelloWorld-installer.exe in the same directory where HelloWorld.nsi resides. When run, installer looks like this:



If we click on Show details button, we can see the following:



We can use ShowInstDetails in order to make installer displaying details by default:



We can use DetailPrint in order to output our custom messages:



And so Installer displays our custom text and Details window by default:




If we want to perform some system checks when installer starts, we can place our code in predefined function .onInit. In the next example, we'll just put displaying message box:



When we run installer, message box is first displayed:



When we click on OK, main window shows:



I used instruction Name to customize title of Installer's windows.

We can do some more serious stuff in .onInit function, like Windows version check. Download GetWindowsVersion.nsh header, create directory headers in the same directory where HelloWorld.nsi is, place GetWindowsVersion.nsh in that new directory (as we want to keep downloaded scripts separately from our work), include that header in the script and call function it exposes - GetWindowsVersion:



Message box displays Windows version:



NOTE: Files with extension nsi are installer script files and files with extension nsh are installer headers.

NOTE: DetailPrint calls from .onInit are ignored.

How to issue periodical execution of DOS command in a single line

Let's say we want to check the state of the socket connection on the port 4016 every second. We can use netstat command to display required information and ping invalid IP address with timeout of 1 second. These two commands can be grouped in the same line with & operator and that group can be put inside infinite FOR loop:

Command:

C:\Users\Scrillex>for /L %a in (0,0,0) do (netstat -an|find "4016" & ping 1.1.1.1 - n 1 -w 1000 >nul)

Output:

C:\Users\Bojan>(netstat -an | find "4016" & ping 1.1.1.1 -n 1 -w 1000 1>nul)
TCP 0.0.0.0:4016 0.0.0.0:0 LISTENING
TCP [::]:4016 [::]:0 LISTENING

C:\Users\Bojan>(netstat -an | find "4016" & ping 1.1.1.1 -n 1 -w 1000 1>nul)
TCP 0.0.0.0:4016 0.0.0.0:0 LISTENING
TCP [::]:4016 [::]:0 LISTENING

C:\Users\Bojan>(netstat -an | find "4016" & ping 1.1.1.1 -n 1 -w 1000 1>nul)
TCP 0.0.0.0:4016 0.0.0.0:0 LISTENING
TCP [::]:4016 [::]:0 LISTENING
^C

To stop the execution of this single line script use CTLR-C.

Safe release of resources

If class allocates unmanaged resources (database connections, sockets, window handles, bitmaps...) it has to implement IDisposable interface with a single method Dispose() which deallocates such resources. When user of this class does not need its instance any more, it has to make sure Dispose() is called - even in the case of an exception. This can be achieved by using try-catch-finally block or with using statement:

Some classes in .NET which implement IDisposable have method Close() along with method Dispose(). Dispose() usually calls Close():

...so it's perfectly safe omitting explicit call to Close() when using using statement.

Resources:
Proper use of the IDisposable interface (SO)
close or dispose (SO)
Does Stream.Dispose always call Stream.Close (and Stream.Flush) (SO)

Creating graphs and diagrams with Doxygen

Install Doxygen and GraphViz.

Open Doxywizard.

In Wizard tab, click on Diagrams topic. Enable Use dot tool from the GraphViz package and select desired graphs to generate.

In Expert tab, click on Project topic. Enable SHORT_NAMES.

In Expert tab, click on Dot topic. Enable HAVE_DOT and set DOT_PATH to relative path to GraphViz binaries (e.g. ../../../Program Files/Graphviz 2.28/bin). Set other attributes by your needs.

When run, Doxygen will create image files for all specified diagrams and create hyperlinks to them across the generated html files.

How to exclude directory from Doxygen parsing

Let's say we want to generate documentation for some code which is at the following path:

C:\development\project1

This project might be using some module (e.g. 3rd party code) which is contained in project1's subdirectory:

C:\development\project1\module1

How to exclude module1 from Doxygen parser? In Doxywizard, open Expert tab and click on Input topic. Find EXCLUDE_PATTERNS attribute and type:

*/module1/*

NOTE:
INPUT attribute should be set to the absolute path to the code of our project:

C:\development\project1

Appending string to STL stringstream

std::stringstream constructor has two optional parameters: string that this stream will be initialized with and the buffer mode. Default mode for stringstream is ios::in|ios::out. Put pointer (the one that points to the location in the buffer where the next output operation will start inserting characters) is always set to location 0 upon stream creation regardless of the buffer content. That explains why Test 2 in the code below yields overwriting of the content on the second output.

If we want to initialize stream during its creation and to make next output operation to append characters, we need to move put pointer to the end of the buffer explicitly - by setting buffer open mode to ios::ate (see Test 3).

main.cpp:


Output:

Test 1:
Contained string: "abc"; Output pointer position: 3
Contained string: "abcdef"; Output pointer position: 6

Test 2:
Contained string: "abc"; Output pointer position: 0
Contained string: "def"; Output pointer position: 3

Test 3:
Contained string: "abc"; Output pointer position: 3
Contained string: "abcdef"; Output pointer position: 6