Testing JMagick

Hi all,

My proposed JUnit testing scheme for JMagick is ready.
Please comment if you disagree on any of these things. If no
objections are made in 5 days I will consider all the below APPROVED
by the jmagick community.

For those that don't know about Unit testing, the idea is to write
some methods that use JMagick in different ways and then to compare
the result against expected values and report an error if the results
are not as expected. See also http://junit.org/ and
http://junit.sourceforge.net/junit3.8.1/index.html .

For JMagick I propose
1) we use JUnit 3 (that is, JDK1.4 no fancy new things from JDK1.5).
2) we maintain a collection of 'correct output' images to compare with
in 'test/correct_output'
3) all accepted tests are in package 'magicktest'. All
new/proposed/not finished/not yet accepted tests are in package
'magicktest.BETA'
4) the goal is to get 100% code coverage, that is: Running the test
suite should activate all JMagick methods.

When 100% code coverage is acieved is will be muuuch easier and safer
to edit the source code of JMagick:
* any errors introduced will show up in the tests (probably, at least :-).
* Any new incompatibilities becaurse of IM code change will
immediately be found.
* we can safely (without breaking anything) move to other ways of
usingIM/GraphicsMagick functions from Java and keep compatibility
(I have automatick exposure/code generation usning JNA in mind -
others consider using the much easier C++ API).



In test/magicktest is the test classes. All test classes are here, and
not in src/ anymore.

Eric's old simpe 'test' (Test.java - but it's really more some
examples of usage than a test) have been renamed to
'OldSimpleTest.java'

Eric's work has been convertet to a JUnit test case in
TestJMagick.java. Please have a look now before you continue reading:
http://jmagick.svn.sourceforge.net/viewvc/jmagick/test/magicktest/TestJMagick.java?view=markup

Here in an example:

   65 ImageInfo info = new ImageInfo(Testtools.path_input + "pics.jpg");
...
   75 image = new MagickImage(info);
...
   82 assertEquals("X resolution is ", 72, image.getXResolution(), 0.1);
   83 assertEquals("Y resolution is ", 72, image.getYResolution(), 0.1);

The methods assertEquals() CHECKS that the return value of
image.getYResolution() is 72  (+/- 0.1) and if this is not the case an
exetion is thrown and the test fails.
Now: THAT is (unit) testing.


Here in another example:

  116 public void testRaise() throws Exception {
  117 // Raise image
  118 image.raiseImage(new Rectangle(0, 0, 10, 20), true);
  119 MagickTesttools.writeAndCompare(image, info, "raised.jpg");
  120 }

Here we use a utility method MagickTesttools which writes the image in
the directory test/actual_output ("test/actual_output/raised.jpg") and
then compares this image with "test/correct_output/raised.jpg". If any
differences are found (within a small margin) then an exception is
thrown and the test fails.


Please check out/update from SVN and try it!
UNIX command line users should be able to just wrtie 'make test'  (but
you need to install junit.jar in lib/ directory).
Windows/GUI users should configure their project to include JUnit
testing and run the class TestJMagick.
Please report any problems you may have.

In test/correct_output is images as they are expected to be. If you
have made an update to JMagick and wants to generate a new set of
'correct' output images you should 'make generateCorrect' or run the
class GenerateCorrectOutput and follow the instructions.


I look forward to hear your reactions!

I hope everyone will try the new test suite on as many platforms as
possible and report any success/failure.

Some tests are dependent on the fonts installed on the system and will
thus probably fail. These have been '_failMightBeOk' in their name (to
not upset you).



--
Jacob Nordfalk
http://javabog.dk
Skype: jacobnordfalk
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