Perl Needs Better Tools
by Matisse Enzer
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Pages: 1, 2, 3, 4, 5, 6
The most basic form of support for unit tests in an IDE is simply to make it easy to execute arbitrary scripts from within the IDE. Create a test.pl for your project and keep adding tests to it or to a t/ subdirectory as you develop, and keep running the script as you make changes. All modern IDEs provide at least this minimal capability.
A more sophisticated level of support for unit tests might resemble the Java
IDE feature for tests written in JUnit, where you can select an existing class
file (a .pm file in Perl) and ask the IDE to create a set of stub
tests for every subroutine in the file. (See JUnit and the Perl module Test::Unit for more on
unit tests.) Furthermore, the IDE should support running a set of tests and
giving simple visual feedback on what passed/failed. The standard approach in
the JUnit world is to show either a "green bar" (all passed) or "red bar"
(something failed) and then allow you to see details on failures. Other
nice-to-have features include calculating code-coverage, providing statistical
summaries of tests, etc.
Figure 9 shows a successful run of a Java test suite with Eclipse.
Figure 9. A successful JUnit test run
Figure 10 shows the same test run, this time with a failure.
Figure 10. A JUnit test run with a failure
A stack trace of the failure message appears in another part of the window
(cropped out here to save space). If you double-click on the test that failed
(testInflate), the IDE will open the file
(BalloonTest, in this case) and navigate to the test function.
The central idea is that the IDE should make it as painless as possible to add and modify and run tests, so you will do more of it during development.
Language-Specific Help
This is a fairly straightforward idea--the IDE should be able to find and
display the appropriate documentation for any keyword in your code, so if you
highlight push and ask for help, you should see the
push entry from the Perl documentation. If you highlight a method
or subroutine or other symbol name from an imported module, the IDE should
display the module's documentation for the selected item. Of course, this
requires that the documentation be available in a consistent, machine-readable
form, which is only sometimes true.
Debugger with Real-Time Display of Results
All modern IDEs offer support for running your code under a debugger, usually with visual display of what's going on, including the state of variables. The Komodo IDE supports debugging Perl that is running either locally or remotely.
Typical support for debugging in an IDE includes the ability to set breakpoints, monitor the state of variables, etc. Basically, the IDE should provide support for all of the features of the debugger itself. Graphical IDEs should provide a visual display of what is going on.
Automatic Code Reformatting
This means automatically or on-demand re-indenting and other reformatting of code. For example, when you cut and paste a chunk of code, the IDE should support reformatting the chunk to match the indentation of its new location. If you change the number of spaces or tabs for each level of indentation, or your convention for the placement of curly braces, then the IDE should support adjusting an entire file or all files in your project.
Seamless Handling of Multiple Languages
Many large software projects involve multiple languages. This is almost universally true in the case of web applications, where the user interface typically uses HTML, CSS, and JavaScript, and the back end uses one or more of Perl, PHP, Java, Python, Ruby, etc. It is very helpful to have development tools that seamlessly integrate work done in all of the languages. This is becoming quite common. For example, both Komodo and Eclipse support multiple languages.
Automated Building and Testing
This feature can be very basic by making it easy to run an arbitrary script from within the IDE and to see its output. This could be as simple as having the IDE configured to have a one-click way of running the traditional Perl module build-and-test commands:
$ perl Makefile.PL
$ make
$ make testA more advanced version of this feature might involve having the IDE create
stub code to test all of the subroutines in an existing file, or to run all of the
scripts in a specified directory under Test::Harness, or to run a
set of tests using Test::Unit::TestRunner
or Test::Unit::TkTestRunner.
(The latter provides a GUI testing framework.)
