Testing Details
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Contents
#org
Testsuite organization and naming conventions
#util
Utilities: abicheck and libv3test
#new
How to write a new test case
#check
Options for running the tests
#debug
Running debug-mode tests
#future
Future
#internals
DejaGNU internals
Testsuite organization and naming conventions
The directory
libsrcdir/testsuite
contains the
individual test cases organized in sub-directories corresponding
to chapters of the C++ standard (detailed below), the dejagnu
test harness support files, and sources to various testsuite
utilities that are packaged in a separate testing library.
All test cases for functionality required by the runtime
components of the C++ standard (ISO 14882) are files within the
following directories.
17_intro
18_support
19_diagnostics
20_util
21_strings
22_locale
23_containers
25_algorithms
26_numerics
27_io
In addition, the following directories include test files:
tr1		  Tests for components as described by the Technical Report on Standard Library Extensions (TR1).
backward	  Tests for backwards compatibility and deprecated features.
demangle	  Tests for __cxa_demangle, the IA 64 C++ ABI demangler
ext		  Tests for extensions.
performance	  Tests for performance analysis, and performance regressions.
thread		  Tests for threads.
Some directories don't have test files, but instead contain
auxiliary information (
#internals
more information
):
config		  Files for the dejagnu test harness.
lib		  Files for the dejagnu test harness.
libstdc++*     	  Files for the dejagnu test harness.
data		  Sample text files for testing input and output.
Within a directory that includes test files, there may be
additional subdirectories, or files.  Originally, test cases
were appended to one file that represented a particular section
of the chapter under test, and was named accordingly. For
instance, to test items related to
21.3.6.1 -
basic_string::find [lib.string::find]
in the standard,
the following was used:
21_strings/find.cc
However, that practice soon became a liability as the test cases
became huge and unwieldy, and testing new or extended
functionality (like wide characters or named locales) became
frustrating, leading to aggressive pruning of test cases on some
platforms that covered up implementation errors. Now, the test
suite has a policy of one file, one test case, which solves the
above issues and gives finer grained results and more manageable
error debugging. As an example, the test case quoted above
becomes:
21_strings/basic_string/find/char/1.cc
21_strings/basic_string/find/char/2.cc
21_strings/basic_string/find/char/3.cc
21_strings/basic_string/find/wchar_t/1.cc
21_strings/basic_string/find/wchar_t/2.cc
21_strings/basic_string/find/wchar_t/3.cc
All new tests should be written with the policy of one test
case, one file in mind.
In addition, there are some special names and suffixes that are
used within the testsuite to designate particular kinds of
tests.
_xin.cc
This test case expects some kind of interactive input in order
to finish or pass. At the moment, the interactive tests are not
run by default. Instead, they are run by hand, like:
g++ 27_io/objects/char/3_xin.cc
cat 27_io/objects/char/3_xin.in | a.out
.in
This file contains the expected input for the corresponding
_xin.cc
test case.
_neg.cc
This test case is expected to fail: it's a negative test. At the
moment, these are almost always compile time errors.
char
This can either be a directory name or part of a longer file
name, and indicates that this file, or the files within this
directory are testing the
char
instantiation of a
template.
wchar_t
This can either be a directory name or part of a longer file
name, and indicates that this file, or the files within this
directory are testing the
wchar_t
instantiation of
a template. Some hosts do not support
wchar_t
functionality, so for these targets, all of these tests will not
be run.
thread
This can either be a directory name or part of a longer file
name, and indicates that this file, or the files within this
directory are testing situations where multiple threads are
being used.
performance
This can either be an enclosing directory name or part of a
specific file name. This indicates a test that is used to
analyze runtime performance, for performance regression testing,
or for other optimization related analysis. At the moment, these
test cases are not run by default.
Utilities: abi_check and libv3test
The testsuite directory also contains some files that implement
functionality that is intended to make writing test cases easier,
or to avoid duplication, or to provide error checking in a way that
is consistent across platforms and test harnesses. A stand-alone
executable, called
abi_check
, and a static library called
libv3test
are constructed. Both of these items are not
installed, and only used during testing.
These files include the following functionality:
testsuite_abi.h
,
testsuite_abi.cc
,
testsuite_abi_check.cc
Creates the executable
abi_check
.
Used to check correctness of symbol versioning, visibility of
exported symbols, and compatibility on symbols in the shared
library, for hosts that support this feature. More information
can be found in the ABI documentation
abi.html
here
testsuite_allocator.h
,
testsuite_allocator.cc
Contains specialized allocators that keep track of construction
and destruction. Also, support for overriding global new and
delete operators, including verification that new and delete
are called during execution, and that allocation over max_size
fails.
testsuite_character.h
Contains
std::char_traits
and
std::codecvt
specializations for a user-defined
POD.
testsuite_hooks.h
,
testsuite_hooks.cc
A large number of utilities, including:
VERIFY
set_memory_limits
verify_demangle
run_tests_wrapped_locale
run_tests_wrapped_env
try_named_locale
try_mkfifo
func_callback
counter
copy_tracker
copy_constructor
assignment_operator
destructor
pod_char, pod_int and associated char_traits specializations
testsuite_io.h
Error, exception, and constraint checking for
std::streambuf, std::basic_stringbuf, std::basic_filebuf
.
testsuite_iterators.h
Wrappers for various iterators.
testsuite_performance.h
A number of class abstractions for performance counters, and
reporting functions including:
time_counter
resource_counter
report_performance
How to write a new test case
The first step in making a new test case is to choose the correct
directory and file name, given the organization as previously
described.
All files are copyright the FSF, and GPL'd: this is very
important.  The first copyright year should correspond to the date
the file was checked in to CVS.
As per the dejagnu instructions, always return 0 from main to
indicate success.
A bunch of utility functions and classes have already been
abstracted out into the testsuite utility library,
libv3test
. To use this functionality, just include the
appropriate header file: the library will automatically be linked
in as part of the testsuite run.
For a test that needs to take advantage of the dejagnu test
harness, what follows below is a list of special keyword that
harness uses. Basically, a test case contains dg-keywords (see
dg.exp) indicating what to do and what kinds of behavior are to be
expected.  New test cases should be written with the new style
DejaGnu framework in mind.
To ease transition, here is the list of dg-keyword documentation
lifted from dg.exp.
# The currently supported options are:
#
# dg-prms-id N
#	set prms_id to N
#
# dg-options "options ..." [{ target selector }]
#	specify special options to pass to the tool (eg: compiler)
#
# dg-do do-what-keyword [{ target/xfail selector }]
#	`do-what-keyword' is tool specific and is passed unchanged to
#	${tool}-dg-test.  An example is gcc where `keyword' can be any of:
#	preprocess|compile|assemble|link|run
#	and will do one of: produce a .i, produce a .s, produce a .o,
#	produce an a.out, or produce an a.out and run it (the default is
#	compile).
#
# dg-error regexp comment [{ target/xfail selector } [{.|0|linenum}]]
#	indicate an error message <regexp> is expected on this line
#	(the test fails if it doesn't occur)
#	Linenum=0 for general tool messages (eg: -V arg missing).
#	"." means the current line.
#
# dg-warning regexp comment [{ target/xfail selector } [{.|0|linenum}]]
#	indicate a warning message <regexp> is expected on this line
#	(the test fails if it doesn't occur)
#
# dg-bogus regexp comment [{ target/xfail selector } [{.|0|linenum}]]
#	indicate a bogus error message <regexp> use to occur here
#	(the test fails if it does occur)
#
# dg-build regexp comment [{ target/xfail selector }]
#	indicate the build use to fail for some reason
#	(errors covered here include bad assembler generated, tool crashes,
#	and link failures)
#	(the test fails if it does occur)
#
# dg-excess-errors comment [{ target/xfail selector }]
#	indicate excess errors are expected (any line)
#	(this should only be used sparingly and temporarily)
#
# dg-output regexp [{ target selector }]
#	indicate the expected output of the program is <regexp>
#	(there may be multiple occurrences of this, they are concatenated)
#
# dg-final { tcl code }
#	add some tcl code to be run at the end
#	(there may be multiple occurrences of this, they are concatenated)
#	(unbalanced braces must be \-escaped)
#
# "{ target selector }" is a list of expressions that determine whether the
# test succeeds or fails for a particular target, or in some cases whether the
# option applies for a particular target.  If the case of `dg-do' it specifies
# whether the test case is even attempted on the specified target.
#
# The target selector is always optional.  The format is one of:
#
# { xfail *-*-* ... } - the test is expected to fail for the given targets
# { target *-*-* ... } - the option only applies to the given targets
#
# At least one target must be specified, use *-*-* for "all targets".
# At present it is not possible to specify both `xfail' and `target'.
# "native" may be used in place of "*-*-*".
Example 1: Testing compilation only
// { dg-do compile }
Example 2: Testing for expected warnings on line 36, which all targets fail
// { dg-warning "string literals" "" { xfail *-*-* } 36
Example 3: Testing for expected warnings on line 36
// { dg-warning "string literals" "" { target *-*-* } 36
Example 4: Testing for compilation errors on line 41
// { dg-do compile }
// { dg-error "no match for" "" { target *-*-* } 41 }
Example 5: Testing with special command line settings, or without the
use of pre-compiled headers, in particular the stdc++.h.gch file. Any
options here will override the DEFAULT_CXXFLAGS and PCH_CXXFLAGS set
up in the normal.exp file.
// { dg-options "-O0" { target *-*-* } }
More examples can be found in the libstdc++-v3/testsuite/*/*.cc files.
Options for running the tests
There are several options for running tests, including testing
the regression tests, testing a subset of the regression tests,
testing the performance tests, testing just compilation, testing
installed tools, etc. In addition, there is a special rule for
checking the exported symbols of the shared library.
You can check the status of the build without installing it
using the dejagnu harness, much like the rest of the gcc tools.
make check
in the
libbuilddir
directory.
or
make check-target-libstdc++-v3
in the
gccbuilddir
directory.
These commands are functionally equivalent and will create a
'testsuite' directory underneath
libbuilddir
containing
the results of the tests. Two results files will be generated:
libstdc++.sum
, which is a PASS/FAIL summary for each
test, and
libstdc++.log
which is a log of the exact
command line passed to the compiler, the compiler output, and
the executable output (if any).
To debug the dejagnu test harness during runs, try invoking with a
specific argument to the variable RUNTESTFLAGS, as below.
make check-target-libstdc++-v3 RUNTESTFLAGS="-v"
or
make check-target-libstdc++-v3 RUNTESTFLAGS="-v -v"
To run a subset of the library tests, try using a command like the
following from the
libbuilddir/testsuite
directory:
runtest --tool libstdc++ normal.exp="`find $srcdir/17_intro -name *.cc`"
There are two ways to run on a simulator: set up DEJAGNU to point to a
specially crafted site.exp, or pass down --target_board flags.
Example flags to pass down for various embedded builds are as follows:
--target=powerpc-eabism (libgloss/sim)
make check-target-libstdc++-v3 RUNTESTFLAGS="--target_board=powerpc-sim"
--target=calmrisc32 (libgloss/sid)
make check-target-libstdc++-v3 RUNTESTFLAGS="--target_board=calmrisc32-sid"
--target=xscale-elf (newlib/sim)
make check-target-libstdc++-v3 RUNTESTFLAGS="--target_board=arm-sim"
Also, here is an example of how to run the libstdc++ testsuite for a
multilibed build directory with different ABI settings:
make check-target-libstdc++-v3 RUNTESTFLAGS='--target_board \"unix{-mabi=32,,-mabi=64}\"'
In addition, there are some testing options that are mostly of
interest to library maintainers and system integrators. As such,
these tests may not work on all cpu and host combinations, and may need to
be executed in the
libbuilddir/testsuite
directory.  These options
include, but are not necessarily limited to, the following:
make testsuite_files
Five files are generated that determine what test files
are run. These files are:
testsuite_files
This is a list of all the test cases that will be run. Each
test case is on a separate line, given with an absolute path
from the
libsrcdir/testsuite
directory.
testsuite_files_interactive
This is a list of all the interactive test cases, using the
same format as the file list above. These tests are not run by default.
testsuite_files_performance
This is a list of all the performance test cases, using the
same format as the file list above. These tests are not run by default.
testsuite_thread
This file indicates that the host system can run tests which
incolved multiple threads.
testsuite_wchar_t
This file indicates that the host system can run the wchar_t
tests, and corresponds to the macro definition
_GLIBCXX_USE_WCHAR_T
in the file c++config.h.
make check-abi
The library ABI can be tested. This involves testing the shared
library against an ABI-defining previous version of symbol exports.
make check-compile
This rule compiles, but does not link or execute, the
testsuite_files
test cases and displays the output on stdout.
make check-performance
This rule runs through the
testsuite_files_performance
test cases and collects information for performance analysis and
can be used to spot performance regressions. Various timing
information is collected, as well as number of hard page faults,
and memory used. This is not run by default, and the implementation
is in flux.
We are interested in any strange failures of the
testsuite; please see
faq/index.html#2_4
FAQ 2.4
for which files to examine.
Running debug-mode tests
To run the libstdc++ test suite under the
debug.html#safe
debug mode
,
edit
libstdc++/scripts/testsuite_flags
to add the
compile-time flag
-D_GLIBCXX_DEBUG
to the result
printed by the
--build-cxx
option. Additionally, add
the
-D_GLIBCXX_DEBUG_PEDANTIC
flag to turn on pedantic
checking. The libstdc++ test suite should produce precisely the same
results under debug mode that it does under release mode: any
deviation indicates an error in either the library or the test
suite.
Future
Shared runs need to be implemented, for targets that support shared libraries.
Diffing of expected output to standard streams needs to be finished off.
The V3 testing framework supports, or will eventually support,
additional keywords for the purpose of easing the job of writing
test cases.  All V3-keywords are of the form
@xxx@
.
Currently plans for supported keywords include:
@require@ <files>
The existence of <files> is essential for the test to complete
successfully.  For example, a test case foo.C using bar.baz as
input file could say
// @require@ bar.baz
The special variable % stands for the rootname, e.g. the
file-name without its `.C' extension.  Example of use (taken
verbatim from 27_io/filebuf.cc)
// @require@ %-*.tst %-*.txt
@diff@ <first-list> <second-list>
After the test case compiles and ran successfully, diff
<first-list> against <second-list>, these lists should
have the same length.  The test fails if diff returns non-zero a
pair of files.
DejaGNU internals
This is information for those looking at making changes to the testsuite
structure, and/or needing to trace dejagnu's actions with --verbose.  This
will not be useful to people who are "merely" adding new tests to the existing
structure.
The first key point when working with dejagnu is the idea of a "tool".
Files, directories, and functions are all implicitly used when they are
named after the tool in use.  Here, the tool will always be "libstdc++".
The
lib
subdir contains support routines.  The
lib/libstdc++.exp
file ("support library") is loaded
automagically, and must explicitly load the others.  For example, files can
be copied from the core compiler's support directory into
lib
.
Some routines in
lib/libstdc++.exp
are callbacks, some are
our own.  Callbacks must be prefixed with the name of the tool.  To easily
distinguish the others, by convention our own routines are named "v3-*".
The next key point when working with dejagnu is "test files".  Any
directory whose name starts with the tool name will be searched for test files.
(We have only one.)  In those directories, any
.exp
file is
considered a test file, and will be run in turn.  Our main test file is called
normal.exp
; it runs all the tests in testsuite_files using the
callbacks loaded from the support library.
The
config
directory is searched for any particular "target
board" information unique to this library.  This is currently unused and sets
only default variables.
See
17_intro/license.html
license.html
for copying conditions.
Comments and suggestions are welcome, and may be sent to
mailto:libstdc++@gcc.gnu.org
the libstdc++ mailing list
.
