+ * [DOCTEST - Description]
+ * [Defining your expectations]
+ * [Expecting an error]
+## DOCTEST - Description
+Run examples embedded in documentation
+With doctest, you can put an example of using your function, right in the
+m-file help. Then, that same example can be used like a unit test, to make
+sure the function still does what the docs say it does.
+Here's a trivial function and its documentation:
+ function sum = add3(value)
+ % ??? Error using ==> add3 ***
+ % add3(value) requires value to be a number
+ % TWO blank lines before the prose description of the function continues
+ error('add3(value) requires value to be a number');
+Here's an example of what happens when something changes and your test fails.
+By the way, output is in the Test Anything Protocol format, which I guess is
+mostly used by Perl people, but it's good enough for now. See
+Normally, the failure report would include a link to somewhere near the
+doctest that failed, but that doesn't format properly in published m-files.
+ doctest('should_fail', 'CreateLinks', 0) % the links don't work in
+ % Has a doctest that should fail.
+## Defining your expectations
+Each time doctest runs a test, it's running a line of code and checking that
+the output is what you say it should be. It knows something is an example
+because it's a line in help('your_function') that starts with '>>'. It knows
+what you think the output should be by starting on the line after >> and
+looking for the next >>, two blank lines, or the end of the documentation.
+If the output of some function will change each time you call it, for instance
+if it includes a random number or a stack trace, you can put ***** (three
+asterisks) where the changing element should be. This acts as a wildcard, and
+will match anything. See the example below.
+Here are some examples of formatting, both ones that work and ones that don't.
+ doctest('formatting', 'CreateLinks', 0)
+ % >> 1 + 1 % should work fine
+ % >> 1 + 1 % comparisons collapse all whitespace, so this passes
+ % >> 1 + 1; % expects no output, since >> is on the next line
+ % >> for I = 1:3 % FAILS: code to run can only be one line long
+ % >> for I = 1:3; disp(I); end % but this works
+ % >> 1 + 4 % FAILS: there aren't 2 blank lines before the prose
+ % Blah blah blah oops! This prose started too soon!
+ % Sometimes you have output that changes each time you run a function
+ % >> dicomuid % FAILS: no wildcard on changing output
+ % 188.8.131.52.4.1.95184.108.40.206.944807727511025110.343357080818013
+ % You can use *** as a wildcard to match this!
+ ok 1 - "1 + 1 % should work fine"
+ ok 2 - "1 + 1 % comparisons collapse all whitespace, so this
+ ok 3 - "1 + 1; % expects no output, since >> is on the next line"
+ not ok 4 - "for I = 1:3 % FAILS: code to run can only be one line long"
+ expected: disp(I) end 1 2 3
+ got : ??? Error: At least one END is missing: the statement may
+ ok 5 - "for I = 1:3; disp(I); end % but this works"
+ not ok 6 - "1 + 4 % FAILS: there aren't 2 blank lines before the
+ expected: ans = 5 Blah blah blah oops! This prose started too soon!
+ not ok 7 - "dicomuid % FAILS: no wildcard on changing output"
+ ok 8 - "dicomuid % passes"
+doctest can deal with errors, a little bit. You might want this to test that
+your function correctly detects that it is being given invalid parameters. But
+if your example will emit other output BEFORE the error message, the current
+version can't deal with that. For more info see Issue #4 on the bitbucket site
+(below). Warnings are different from errors, and they work fine.
+ doctest('errors', 'CreateLinks', 0)
+ % Errors and doctest - demonstrates a current limitation of doctest
+ % >> not_a_real_function(42)
+ % ??? Undefined function or method 'not_a_real_function' for input
+ % arguments of type 'double'.
+ % >> disp('if at first you don''t succeed...'); error('nevermind')
+ % if at first you don't succeed...
+ ok 1 - "not_a_real_function(42)"
+ not ok 2 - "disp('if at first you don''t succeed...'); error('nevermind')"
+ expected: if at first you don't succeed... ??? nevermind
+All adjascent white space is collapsed into a single space before comparison,
+so right now doctest can't detect a failure that's purely a whitespace
+It can't run lines that are longer than one line of code (so, for example, no
+loops that take more than one line). This is difficult because I haven't found
+a good way to mark these subsequent lines as part-of-the-source-code rather
+I haven't found a good way of isolating the variables that you define in the
+tests from the variables used to run the test. So, don't run CLEAR in your
+doctest, and don't expect WHO/WHOS to work right, and don't mess with any
+variables that start with doctest_. :-/
+When you're working on writing/debugging a Matlab class, you might need to run
+'clear classes' to get correct results from doctests (this is a general
+problem with developing classes in Matlab).
+The latest version from the original author, Thomas Smith, is available at
+The bugtracker is also there, let me know if you encounter any problems!
+Published with MATLAB® 7.9
+ : http://testanything.org/
+ : http://bitbucket.org/tgs/doctest-for-matlab/src