a little madness

A man needs a little madness, or else he never dares cut the rope and be free -Nikos Kazantzakis

Zutubi

Archive for December, 2009

Cygwin, Svn and Windows 7

Yes, I use windows. Please don’t hate me for it. And yes, I use cygwin because I like to be able to use the command line tool that *nix provides. I will probably move away from windows someday, however for now it is what I am comfortable and most productive with.

So when I upgraded my machine to Windows 7 the other day, one of the first things I did was install Cygwin. Having done this numerous times in the past, I went straight to the download link and didn’t bother reading any of the useful content on the home page. Big Mistake.

The first sign that I had that there was trouble looming was this

Can’t create tunnel: Resource temporarily unavailable

when running any svn commands. I was aware that Windows 7 had significantly different security setup to XP, so I started looking around to see there was any help available at the usual locations. Alas, I came up empty. What was even more curious was that the error was completely random. Sometimes a command would work, other times it would not.

Queue a lot of frustration and cursing until I finally saw the cygwin home page again and this time read the note that

Note that Windows 7 and later will only be supported starting with the 1.7 version of Cygwin.

Cygwin 1.7 is still in beta testing, so figured I would give it a go and keep fingers crossed that what I need to work still works.

A download and svn checkout later and I run into this

/usr/bin/svn.exe: error while loading shared libraries: ?: cannot open
shared object file: No such file or directory

Was I out of luck? Fortunately my trusty friend google came to the rescue this time.

So for anyone else that is using cygwin and running into problems, I hope you find this helpful.

Pulse 2.1.11: Get More From Your Build Agents

The latest Pulse 2.1 beta build, 2.1.11, has just been freshly baked. This build includes several new features and improvements. Prominent among them is a new “statistics” tab for agents. This tab lists various figures such as the number of recipes the agent executes each day and how long the average recipe keeps the agent busy. Statistics are also shown for agent utilisation, including a pie chart that makes it easy to visualise:

agent utilisation chart

This allows you to see if you are getting the most out of your agent machines. If you do notice a machine is underutilised, another new feature could help identify the cause: compatibility information for projects and agents. Pulse matches builds to agents by considering if the resources required for the project are all available on the agent. Now when you configure requirements, Pulse shows you which agents those requirements are compatible with. On the flip side, when configuring an agent’s available resources, Pulse shows you which projects those resources satisfy.

Other highlights in this build:

  • Optional compression of large build logs (on by default).
  • Visual indicators of which users are logged in, and last access times for all users.
  • Support for Subversion 1.6 working copies for personal builds.
  • Actions can now be performed on all descendants of a project or agent template (e.g. disable all agents with one click).
  • New options to terminate a build early if a critical stage or number of stages have already failed.
  • The system/agent info tabs now show the Pulse process environment (visible to administrators only).
  • Use of bare git repositories on the Pulse master to save disk space.

Yes, we have been busy :). Get over to our website and download the beta now — it’s free to try, and a free upgrade for customers with current support contracts!

Boost.Test XML Reports with Boost.Build

My previous post Using Boost.Test with Boost.Build illustrated how to build and run Boost.Tests tests with the Boost.Build build system. For my own purposes I wanted to take this one step further by integrating Boost.Test results with continuous integration builds in Pulse.

To do this, I needed to get Boost.Test to produce XML output, at the right level of detail, which can be read by Pulse. This is another topic I have covered to some extent before: the key part being to pass the arguments “–log_format=XML –log_level=test_suite” to the Boost.Test binaries. The missing link is how to achieve this using Boost.Build’s run task. Recall that the syntax for the run task is as follows:

rule run (
    sources + :
    args * :
    input-files * :
    requirements * :
    target-name ? :
    default-build * )

Notice in particular that you can pass arguments just after the sources. So I updated my Jamfile to the following:

using testing ;
lib boost_unit_test_framework ;
run NumberTest.cpp /libs/number//number boost_unit_test_framework
    : --log_format=XML --log_level=test_suite
    ;

and lo, the test output was now in XML format:

$ cat bin/NumberTest.test/gcc-4.4.1/debug/NumberTest.output 
<TestLog><TestSuite name="Number"><TestSuite name="NumberSuite"><TestCase name="checkPass"><TestingTime>0</TestingTime></TestCase><TestCase name="checkFailure"><Error file="NumberTest.cpp" line="15">check Number(2).add(2) == Number(5) failed [4 != 5]</Error><TestingTime>0</TestingTime></TestCase></TestSuite></TestSuite></TestLog>
*** 1 failure detected in test suite "Number"

EXIT STATUS: 201

The output will not exactly win awards: it has no <?xml …?> declaration, no formatting, and thanks to Boost.Test contains trailing junk. We’ve made sure that the processing in Pulse 2.1 takes care of this, though.

If you are a Pulse user looking to integrate Pulse and Boost.Test, you might also be interested in a new Cookbook article that I’ve written up on this topic.

Using Boost.Test with Boost.Build

In my earlier post C++ Unit Testing With Boost.Test I used make to build my sample code — largely because that is what I am more familiar with. If you’re using Boost for testing, though, you should also consider using it for building. From what I’ve seen you get a lot of functionality for free with Boost.Build if you’re willing to climb the learning curve. In order to help, I’ve put together a simple tutorial that combines Boost.Test and Boost.Build.

Prerequisites

In this tutorial I’m assuming you have Boost installed already. If not, you can refer to my earlier post or the Boost Getting Started Guide.

Installing Boost.Build

If, like me, you installed Boost by using the package manager on your Linux box, you may still not have Boost.Build installed. On Debian-based systems, Boost.Build requires two extra packages:

$ sudo apt-get install bjam boost-build

The bjam package installs Boost’s variant of the jam build tool, whereas the boost-build package installs a set of bjam configurations that form the actual Boost.Build system.

If you’re not lucky enough to have a boost-build package or equivalent, you can get a pre-built bjam binary and sources for Boost.Build, see the official documentation for details.

Once you have everything set up, you should be able to run bjam –version and see similar to the following output:

$ bjam --version
Boost.Build V2 (Milestone 12)
Boost.Jam 03.1.16

If you don’t see details of the Boost.Build version then it is likely you have only installed bjam and not the full Boost.Build system.

Sample Projects

To demonstrate Boost.Build’s support for multiple projects in a single tree, I split my sample code into two pieces: a simple library, and the test code itself. The library consists of a single Number class, which is an entirely contrived wrapper around an int. The test code exercises this library, and thus needs to link against it.

Boost.Build isn’t particularly fussy about how you lay out your projects, so I went for a simple structure:

$ ls -R
.:
Jamroot  number  test

./number:
Jamfile  Number.cpp  Number.hpp

./test:
Jamfile  NumberTest.cpp

The Jamroot and Jamfiles are build files used by Boost.Build. They are in the same format — the difference in name is used to indicate the top level of the project. Boost.Build subprojects inherit configuration from parent projects by searching up the directory tree for a Jamfile, and will stop when a Jamroot is reached.

Top Level

The top level Jamroot file is incredibly simple in this case:

use-project /libs/number : number ;

In fact this line isn’t even strictly necessary, but it is good practice. It assigns the symbolic name “/libs/number” to the project in the “number” subdirectory. It’s overkill for such a simple example, but this abstraction means our test project will have no dependency on the exact location of the number library. If we refactored and moved the library into a subdirectory called “math”, then we would only need to update the Jamroot.

Number Library

As mentioned above, the number library is a contrived wrapper around an int that I created simply for illustration. The interface for this library is defined in Number.hpp:

#ifndef MY_LIBRARY_H
#define MY_LIBRARY_H

#include <iostream>

class Number
{
public:
  Number(int value);

  bool operator==(const Number& other) const;

  Number add(const Number& other) const;
  Number subtract(const Number& other) const;

  int getValue() const;

private:
  int value;
};

std::ostream& operator<<(std::ostream& output, const Number& n);

#endif

Of greater interest is the Jamfile used to build the library:

project : usage-requirements <include>. ;
lib number : Number.cpp ;

Note that the single “lib” line is all that is required to build the library. The lib rule is one of the core rules provided by Boost.Build, and follows its common syntax:

rule rule-name (
     main-target-name :
     sources + :
     requirements * :
     default-build * :
     usage-requirements * )

So in this case we are instructing Boost.Build to create a library named “number” from the sources “Number.cpp”.

The project declaration, which adds usage-requirements, is a convenience for consumers of this library. This tells the build system that any project that uses the number library should have this directory “.” added to its include path. This makes it easy for those projects to include Number.hpp.

We can build the library by running bjam in the number directory:

$  bjam
...found 12 targets...
...updating 5 targets...
MkDir1 ../number/bin
MkDir1 ../number/bin/gcc-4.4.1
MkDir1 ../number/bin/gcc-4.4.1/debug
gcc.compile.c++ ../number/bin/gcc-4.4.1/debug/Number.o
gcc.link.dll ../number/bin/gcc-4.4.1/debug/libnumber.so
...updated 5 targets...

Note that by default Boost.Build produces a dynamic library, and outputs the built artifacts into configuration-specific subdirectories.

Test Project

Finally, our test project consists of a single source file, NumberTest.cpp, with a single test suite:

#define BOOST_TEST_DYN_LINK
#define BOOST_TEST_MODULE Number
#include <boost/test/unit_test.hpp>
#include <Number.hpp>

BOOST_AUTO_TEST_SUITE(NumberSuite)

BOOST_AUTO_TEST_CASE(checkPass)
{
  BOOST_CHECK_EQUAL(Number(2).add(2), Number(4));
}

BOOST_AUTO_TEST_CASE(checkFailure)
{
  BOOST_CHECK_EQUAL(Number(2).add(2), Number(5));
}

BOOST_AUTO_TEST_SUITE_END()

Note the definition of BOOST_TEST_DYN_LINK: this is essential to link against the Boost.Test dynamic library. Other than that the code is fairly self explanatory.

Again, the Jamfile is what we are really interested in here:

using testing ;
lib boost_unit_test_framework ;
run NumberTest.cpp /libs/number//number boost_unit_test_framework ;

Starting from the top, the “using testing” line includes Boost.Build’s support for Boost.Test. This support includes rules for building and running tests; for example it defines the “run” rule which is used later in the file.

The “lib” line declares a pre-built library (note that it has no sources) named “boost_unit_test_framework”. We use this later for linking against the Boost.Test dynamic library.

Finally, the “run” rule is used to define how to build an run a Boost.Test executable. The syntax for this rule is:

rule run (
    sources + :
    args * :
    input-files * :
    requirements * :
    target-name ? :
    default-build * )

In our sources we include both the source file and the two libraries that we require. Note that we refer to the number project using the symbolic name declared in our Jamroot.

To build and run the tests, we simply execute bjam in the test directory:

$ bjam
...found 29 targets...
...updating 8 targets...
MkDir1 bin
MkDir1 bin/NumberTest.test
MkDir1 bin/NumberTest.test/gcc-4.4.1
MkDir1 bin/NumberTest.test/gcc-4.4.1/debug
gcc.compile.c++ bin/NumberTest.test/gcc-4.4.1/debug/NumberTest.o
gcc.link bin/NumberTest.test/gcc-4.4.1/debug/NumberTest
testing.capture-output bin/NumberTest.test/gcc-4.4.1/debug/NumberTest.run
====== BEGIN OUTPUT ======
Running 2 test cases...
NumberTest.cpp(18): error in "checkFailure": check Number(2).add(2) == Number(5) failed [4 != 5]

*** 1 failure detected in test suite "Number"

EXIT STATUS: 201
====== END OUTPUT ======
&lt;snipped diagnostics&gt;
...failed testing.capture-output bin/NumberTest.test/gcc-4.4.1/debug/NumberTest.run...
...failed updating 1 target...
...skipped 1 target...
...updated 6 targets...

Note that the build fails as I have deliberately created a failing test case. The full output is somewhat longer due to the diagnostics given.

Wrap Up

That’s it! The impressive part is how simple it is to build two projects with an interdependency and run a test suite. In total the three build files include just six lines! And I haven’t even explored the fact that Boost.Build allows you to easily build across multiple platforms using various toolchains and configurations.

The hardest part is working through enough of the documentation to find out the few lines you need — hopefully this tutorial goes some way to removing that barrier.

Fencing Selenium With Xephyr

Earlier in the year I put Selenium in a cage using Xnest. This allows me to run browser-popping tests in the background without disturbing my desktop or (crucially) stealing my focus.

On that post Rohan stopped by to mention a nice alternative to Xnest: Xephyr. As the Xephyr homepage will tell you:

Xephyr is a kdrive based X Server which targets a window on a host X Server as its framebuffer. Unlike Xnest it supports modern X extensions ( even if host server doesn’t ) such as Composite, Damage, randr etc (no GLX support now). It uses SHM Images and shadow framebuffer updates to provide good performance. It also has a visual debugging mode for observing screen updates.

It sounded sweet, but I hadn’t tried it out until recently, on a newer box where I didn’t already have Xnest setup. The good news is the setup is as simple as with Xnest in my prior post:

  1. Install Xephyr: which runs an X server inside a window:
    $ sudo apt-get install xserver-xephyr
  2. Install a simple window manager: again, for old times’ sake, I’ve gone for fvwm:
    $ sudo apt-get install fvwm
  3. Start Xephyr: choose an unused display number (most standard setups will already be using 0) — I chose 1. As with Xnest, the -ac flag turns off access control, which you might want to be more careful about. My choice of window size is largely arbitrary:
    $ Xephyr :1 -screen 1024×768 -ac &
  4. Set DISPLAY: so that subsequent X programs connect to Xephyr, you need to set the environment variable DISPLAY to whatever you passed as the first argument to Xephyr above:
    $ export DISPLAY=:1
  5. Start your window manager: to manage windows in your nested X instance:
    $ fvwm &
  6. Run your tests: however you normally would:
    $ ant accept.master

Then just sit back and watch the browsers launched by Selenium trapped in the Xephyr window. Let’s see them take your focus now!