Next: Demonstration Functions, Up: Test and Demo Functions [Contents][Index]
Perform tests from the first file in the loadpath matching name.
test can be called as a command or as a function. Called with
a single argument name, the tests are run interactively and stop
after the first error is encountered.
With a second argument the tests which are performed and the amount of output is selected.
"quiet"Don’t report all the tests as they happen, just the errors.
"normal"Report all tests as they happen, but don’t do tests which require user interaction.
"verbose"Do tests which require user interaction.
The argument fid can be used to allow batch processing. Errors
can be written to the already open file defined by fid, and
hopefully when Octave crashes this file will tell you what was happening
when it did. You can use stdout if you want to see the results as
they happen. You can also give a file name rather than an fid, in
which case the contents of the file will be replaced with the log from
the current test.
Called with a single output argument success, test returns
true if all of the tests were successful. Called with two output arguments
n and max, the number of successful tests and the total number
of tests in the file name are returned.
If the second argument is the string "grabdemo", the contents of
the demo blocks are extracted but not executed. Code for all code blocks
is concatenated and returned as code with idx being a vector
of positions of the ends of the demo blocks.
If the second argument is "explain", then name is ignored
and an explanation of the line markers used is written to the file
fid.
test scans the named script file looking for lines which start
with the identifier ‘%!’. The prefix is stripped off and the rest
of the line is processed through the Octave interpreter. If the code
generates an error, then the test is said to fail.
Since eval() will stop at the first error it encounters, you must
divide your tests up into blocks, with anything in a separate
block evaluated separately. Blocks are introduced by valid keywords like
test, function, or assert immediately following ‘%!’.
A block is defined by indentation as in Python. Lines beginning with
‘%!<whitespace>’ are part of the preceeding block.
For example:
%!test error ("this test fails!");
%!test "test doesn't fail. it doesn't generate an error";
When a test fails, you will see something like:
***** test error ("this test fails!")
!!!!! test failed
this test fails!
Generally, to test if something works, you want to assert that it produces a correct value. A real test might look something like
%!test
%! a = [1, 2, 3; 4, 5, 6]; B = [1; 2];
%! expect = [ a ; 2*a ];
%! get = kron (b, a);
%! if (any (size (expect) != size (get)))
%! error ("wrong size: expected %d,%d but got %d,%d",
%! size (expect), size (get));
%! elseif (any (any (expect != get)))
%! error ("didn't get what was expected.");
%! endif
To make the process easier, use the assert function. For example,
with assert the previous test is reduced to:
%!test %! a = [1, 2, 3; 4, 5, 6]; b = [1; 2]; %! assert (kron (b, a), [ a; 2*a ]);
assert can accept a tolerance so that you can compare results
absolutely or relatively. For example, the following all succeed:
%!test assert (1+eps, 1, 2*eps) # absolute error %!test assert (100+100*eps, 100, -2*eps) # relative error
You can also do the comparison yourself, but still have assert generate the error:
%!test assert (isempty ([])) %!test assert ([1, 2; 3, 4] > 0)
Because assert is so frequently used alone in a test block, there
is a shorthand form:
%!assert (…)
which is equivalent to:
%!test assert (…)
Occasionally a block of tests will depend on having optional
functionality in Octave. Before testing such blocks the availability of
the required functionality must be checked. A %!testif HAVE_XXX
block will only be run if Octave was compiled with functionality
‘HAVE_XXX’. For example, the sparse single value decomposition,
svds(), depends on having the ARPACK library. All of the tests
for svds begin with
%!testif HAVE_ARPACK
Review config.h or octave_config_info ("features") to see some
of the possible values to check.
Sometimes during development there is a test that should work but is
known to fail. You still want to leave the test in because when the
final code is ready the test should pass, but you may not be able to
fix it immediately. To avoid unnecessary bug reports for these known
failures, mark the block with xtest rather than test:
%!xtest assert (1==0)
%!xtest fail ("success=1", "error")
In this case, the test will run and any failure will be reported.
However, testing is not aborted and subsequent test blocks will be
processed normally. Another use of xtest is for statistical
tests which should pass most of the time but are known to fail
occasionally.
Each block is evaluated in its own function environment, which means
that variables defined in one block are not automatically shared
with other blocks. If you do want to share variables, then you
must declare them as shared before you use them. For example, the
following declares the variable a, gives it an initial value (default
is empty), and then uses it in several subsequent tests.
%!shared a %! a = [1, 2, 3; 4, 5, 6]; %!assert (kron ([1; 2], a), [ a; 2*a ]); %!assert (kron ([1, 2], a), [ a, 2*a ]); %!assert (kron ([1,2; 3,4], a), [ a,2*a; 3*a,4*a ]);
You can share several variables at the same time:
%!shared a, b
You can also share test functions:
%!function a = fn (b) %! a = 2*b; %!endfunction %!assert (fn(2), 4);
Note that all previous variables and values are lost when a new shared block is declared.
Remember that %!function begins a new block and that
%!endfunction ends this block. Be aware that until a new block
is started, lines starting with ‘%!<space>’ will be discarded as comments.
The following is nearly identical to the example above, but does nothing.
%!function a = fn (b) %! a = 2*b; %!endfunction %! assert (fn(2), 4);
Because there is a space after ‘%!’ the assert statement does
not begin a new block and this line is treated as a comment.
Error and warning blocks are like test blocks, but they only succeed
if the code generates an error. You can check the text of the error
is correct using an optional regular expression <pattern>.
For example:
%!error <passes!> error ("this test passes!");
If the code doesn’t generate an error, the test fails. For example:
%!error "this is an error because it succeeds.";
produces
***** error "this is an error because it succeeds."; !!!!! test failed: no error
It is important to automate the tests as much as possible, however
some tests require user interaction. These can be isolated into
demo blocks, which if you are in batch mode, are only run when
called with demo or the verbose option to test.
The code is displayed before it is executed. For example,
%!demo %! t = [0:0.01:2*pi]; x = sin (t); %! plot (t, x); %! # you should now see a sine wave in your figure window
produces
funcname example 1: t = [0:0.01:2*pi]; x = sin (t); plot (t, x); # you should now see a sine wave in your figure window Press <enter> to continue:
Note that demo blocks cannot use any shared variables. This is so that they can be executed by themselves, ignoring all other tests.
If you want to temporarily disable a test block, put # in place
of the block type. This creates a comment block which is echoed
in the log file but not executed. For example:
%!#demo %! t = [0:0.01:2*pi]; x = sin (t); %! plot (t, x); %! # you should now see a sine wave in your figure window
The following trivial code snippet provides examples for the use of fail, assert, error and xtest:
function output = must_be_zero (input)
if (input != 0)
error ("Non-zero input!")
endif
output = input;
endfunction
%!fail ("must_be_zero (1)");
%!assert (must_be_zero (0), 0);
%!error <Non-zero> must_be_zero (1);
%!xtest error ("This code generates an error");
When putting this a file must_be_zero.m, and running the test, we see
test must_be_zero verbose
⇒
>>>>> /path/to/must_be_zero.m
***** fail ("must_be_zero (1)");
***** assert (must_be_zero (0), 0);
***** error <Non-zero> must_be_zero (1);
***** xtest error ("This code generates an error");
!!!!! known failure
This code generates an error
PASSES 4 out of 4 tests (1 expected failures)
%!testcheck that entire block is correct
%!testif HAVE_XXXcheck block only if Octave was compiled with feature HAVE_XXX.
%!xtestcheck block, report a test failure but do not abort testing.
%!errorcheck for correct error message
%!warningcheck for correct warning message
%!demodemo only executes in interactive mode
%!#comment: ignore everything within the block
%!shared x,y,zdeclare variables for use in multiple tests
%!functiondefine a function for use in multiple tests
%!endfunctionclose a function definition
%!assert (x, y, tol)shorthand for %!test assert (x, y, tol)
You can also create test scripts for built-in functions and your own C++
functions. To do so, put a file with the bare function name (no .m
extension) in a directory in the load path and it will be discovered by
the test function. Alternatively, you can embed tests directly in your
C++ code:
/*
%!test disp ("this is a test")
*/
or
#if 0
%!test disp ("this is a test")
#endif
However, in this case the raw source code will need to be on the load
path and the user will have to remember to type
test ("funcname.cc").
Produce an error if the specified condition is not met. assert can
be called in three different ways.
assert (cond)assert (cond, errmsg, …)assert (cond, msg_id, errmsg, …)Called with a single argument cond, assert produces an
error if cond is zero. When called with more than one argument the
additional arguments are passed to the error function.
assert (observed, expected)Produce an error if observed is not the same as expected. Note that observed and expected can be scalars, vectors, matrices, strings, cell arrays, or structures.
assert (observed, expected, tol)Produce an error if observed is not the same as expected but equality
comparison for numeric data uses a tolerance tol.
If tol is positive then it is an absolute tolerance which will produce
an error if abs (observed - expected) > abs (tol).
If tol is negative then it is a relative tolerance which will produce
an error if abs (observed - expected) >
abs (tol * expected). If expected is zero tol will
always be interpreted as an absolute tolerance. If tol is not scalar
its dimensions must agree with those of observed and expected
and tests are performed on an element-wise basis.
Return true if code fails with an error message matching pattern, otherwise produce an error. Note that code is a string and if code runs successfully, the error produced is:
expected error <.> but got none
Code must be in the form of a string that may be passed by
fail to the Octave interpreter via the evalin function,
that is, a (quoted) string constant or a string variable.
If called with two arguments, the behavior is similar to
fail (code), except the return value will only be true if
code fails with an error message containing pattern (case sensitive).
If the code fails with a different error to that given in pattern,
the message produced is:
expected <pattern>
but got <text of actual error>
The angle brackets are not part of the output.
Called with three arguments, the behavior is similar to
fail (code, pattern), but produces an error if no
warning is given during code execution or if the code fails.
See also: assert.
Next: Demonstration Functions, Up: Test and Demo Functions [Contents][Index]