Unit tests

Trip Volpe mraccident at gmail.com
Sun Feb 21 16:10:37 PST 2010


Paul D. Anderson Wrote:

> I know there are a lot of D programmers rooting for enhancements to the unittests in D (and I don't want to re-open that discussion), but are there any of the best and brightest among us who have developed a module to allow for named tests and tests that keep running following a failure, etc.
> 
> I apologize if this is a question that's already been asked and answered.
> 
> Paul

Nick Sabalausky's deferAssert is one take on it, though it's rendered a bit verbose by mixin syntax. I'm writing a small module for this myself -- my main goal is to provide simple and intuitive syntax, and I'm willing to give up a little functionality for that. Here's what a typical unit test might look like:

unittest
{
    begin( "testName" );

    int foo = 3, baz = 42;

    bool isOnFire() { return true; }

    expectEqual! ( foo, 10 );
    expectEqual! ( baz, 42 );
    expect( !isOnFire(), "danger: code is on fire!" );
}


And here is a sample output:

Testing 'parser'...                               [OK]
Testing 'lexer'...                                [FAIL]
    FAILED TEST: lexNumber
       lexer.d(517): expected: pos == 6; actual: '8', '6'
Testing 'units'...                                [OK]
Testing 'teststuff'...                            [FAIL]
    FAILED TEST: testName
       teststuff.d(12): expected: foo == 10; actual: '3', '10'
       teststuff.d(14): danger: code is on fire!

It integrates quite smoothly so far, using Runtime.moduleUnitTester() to set a custom runner for all unit tests that tracks errors, test names, and so forth and provides the comprehensive output listed above. I also added console text coloring, so on Windows and Linux those "[OK]"s will be in bright green and the "[FAIL]" tags in red. :-)

Having to use begin() at the start of the test is a bit of a kludge, and ideally D would allow tests to be named by unittest("testName") { } or some similar syntax.

Also, my expectEqual template is hurt somewhat by a limitation in D -- it uses template alias parameters so that it can print a string representation of the symbols that were given to it in a diagnostic message, e.g., "expected: foo == 10". Unfortunately, alias parameters can only alias single D symbols -- so expectEqual!(foo, 10) is okay, but expectEqual!(someArray[1], someFunc()) is not.

In another posting here ( http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=105682 ) I suggested allowing template alias parameters to alias compound expressions, which would solve the above problem and make unit testing much more awesome.  :D

Anyway, as my test module develops into something a little more robust and finished-looking, I'd be happy to post the code if anybody is interested.



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