xref: /external/chromium_org/testing/gtest/README

Google C++ Testing Framework
============================

http://code.google.com/p/googletest/

Overview
--------

Google's framework for writing C++ tests on a variety of platforms
(Linux, Mac OS X, Windows, Windows CE, Symbian, etc).  Based on the
xUnit architecture.  Supports automatic test discovery, a rich set of
assertions, user-defined assertions, death tests, fatal and non-fatal
failures, various options for running the tests, and XML test report
generation.

Please see the project page above for more information as well as the
mailing list for questions, discussions, and development.  There is
also an IRC channel on OFTC (irc.oftc.net) #gtest available.  Please
join us!

Requirements for End Users
--------------------------

Google Test is designed to have fairly minimal requirements to build
and use with your projects, but there are some.  Currently, we support
Linux, Windows, Mac OS X, and Cygwin.  We will also make our best
effort to support other platforms (e.g. Solaris, AIX, and z/OS).
However, since core members of the Google Test project have no access
to these platforms, Google Test may have outstanding issues there.  If
you notice any problems on your platform, please notify
googletestframework@googlegroups.com.  Patches for fixing them are
even more welcome!

### Linux Requirements ###

These are the base requirements to build and use Google Test from a source
package (as described below):
  * GNU-compatible Make or gmake
  * POSIX-standard shell
  * POSIX(-2) Regular Expressions (regex.h)
  * A C++98-standard-compliant compiler

### Windows Requirements ###

  * Microsoft Visual C++ 7.1 or newer

### Cygwin Requirements ###

  * Cygwin 1.5.25-14 or newer

### Mac OS X Requirements ###

  * Mac OS X 10.4 Tiger or newer
  * Developer Tools Installed

Also, you'll need CMake 2.6.4 or higher if you want to build the
samples using the provided CMake script, regardless of the platform.

Requirements for Contributors
-----------------------------

We welcome patches.  If you plan to contribute a patch, you need to
build Google Test and its own tests from an SVN checkout (described
below), which has further requirements:

  * Python version 2.3 or newer (for running some of the tests and
    re-generating certain source files from templates)
  * CMake 2.6.4 or newer

Getting the Source
------------------

There are two primary ways of getting Google Test's source code: you
can download a stable source release in your preferred archive format,
or directly check out the source from our Subversion (SVN) repository.
The SVN checkout requires a few extra steps and some extra software
packages on your system, but lets you track the latest development and
make patches much more easily, so we highly encourage it.

### Source Package ###

Google Test is released in versioned source packages which can be
downloaded from the download page [1].  Several different archive
formats are provided, but the only difference is the tools used to
manipulate them, and the size of the resulting file.  Download
whichever you are most comfortable with.

  [1] http://code.google.com/p/googletest/downloads/list

Once the package is downloaded, expand it using whichever tools you
prefer for that type.  This will result in a new directory with the
name "gtest-X.Y.Z" which contains all of the source code.  Here are
some examples on Linux:

  tar -xvzf gtest-X.Y.Z.tar.gz
  tar -xvjf gtest-X.Y.Z.tar.bz2
  unzip gtest-X.Y.Z.zip

### SVN Checkout ###

To check out the main branch (also known as the "trunk") of Google
Test, run the following Subversion command:

  svn checkout http://googletest.googlecode.com/svn/trunk/ gtest-svn

Setting up the Build
--------------------

To build Google Test and your tests that use it, you need to tell your
build system where to find its headers and source files.  The exact
way to do it depends on which build system you use, and is usually
straightforward.

### Generic Build Instructions ###

Suppose you put Google Test in directory ${GTEST_DIR}.  To build it,
create a library build target (or a project as called by Visual Studio
and Xcode) to compile

  ${GTEST_DIR}/src/gtest-all.cc

with ${GTEST_DIR}/include in the system header search path and ${GTEST_DIR}
in the normal header search path.  Assuming a Linux-like system and gcc,
something like the following will do:

  g++ -isystem ${GTEST_DIR}/include -I${GTEST_DIR} \
      -pthread -c ${GTEST_DIR}/src/gtest-all.cc
  ar -rv libgtest.a gtest-all.o

(We need -pthread as Google Test uses threads.)

Next, you should compile your test source file with
${GTEST_DIR}/include in the system header search path, and link it
with gtest and any other necessary libraries:

  g++ -isystem ${GTEST_DIR}/include -pthread path/to/your_test.cc libgtest.a \
      -o your_test

As an example, the make/ directory contains a Makefile that you can
use to build Google Test on systems where GNU make is available
(e.g. Linux, Mac OS X, and Cygwin).  It doesn't try to build Google
Test's own tests.  Instead, it just builds the Google Test library and
a sample test.  You can use it as a starting point for your own build
script.

If the default settings are correct for your environment, the
following commands should succeed:

  cd ${GTEST_DIR}/make
  make
  ./sample1_unittest

If you see errors, try to tweak the contents of make/Makefile to make
them go away.  There are instructions in make/Makefile on how to do
it.

### Using CMake ###

Google Test comes with a CMake build script (CMakeLists.txt) that can
be used on a wide range of platforms ("C" stands for cross-platform.).
If you don't have CMake installed already, you can download it for
free from http://www.cmake.org/.

CMake works by generating native makefiles or build projects that can
be used in the compiler environment of your choice.  The typical
workflow starts with:

  mkdir mybuild       # Create a directory to hold the build output.
  cd mybuild
  cmake ${GTEST_DIR}  # Generate native build scripts.

If you want to build Google Test's samples, you should replace the
last command with

  cmake -Dgtest_build_samples=ON ${GTEST_DIR}

If you are on a *nix system, you should now see a Makefile in the
current directory.  Just type 'make' to build gtest.

If you use Windows and have Visual Studio installed, a gtest.sln file
and several .vcproj files will be created.  You can then build them
using Visual Studio.

On Mac OS X with Xcode installed, a .xcodeproj file will be generated.

### Legacy Build Scripts ###

Before settling on CMake, we have been providing hand-maintained build
projects/scripts for Visual Studio, Xcode, and Autotools.  While we
continue to provide them for convenience, they are not actively
maintained any more.  We highly recommend that you follow the
instructions in the previous two sections to integrate Google Test
with your existing build system.

If you still need to use the legacy build scripts, here's how:

The msvc\ folder contains two solutions with Visual C++ projects.
Open the gtest.sln or gtest-md.sln file using Visual Studio, and you
are ready to build Google Test the same way you build any Visual
Studio project.  Files that have names ending with -md use DLL
versions of Microsoft runtime libraries (the /MD or the /MDd compiler
option).  Files without that suffix use static versions of the runtime
libraries (the /MT or the /MTd option).  Please note that one must use
the same option to compile both gtest and the test code.  If you use
Visual Studio 2005 or above, we recommend the -md version as /MD is
the default for new projects in these versions of Visual Studio.

On Mac OS X, open the gtest.xcodeproj in the xcode/ folder using
Xcode.  Build the "gtest" target.  The universal binary framework will
end up in your selected build directory (selected in the Xcode
"Preferences..." -> "Building" pane and defaults to xcode/build).
Alternatively, at the command line, enter:

  xcodebuild

This will build the "Release" configuration of gtest.framework in your
default build location.  See the "xcodebuild" man page for more
information about building different configurations and building in
different locations.

If you wish to use the Google Test Xcode project with Xcode 4.x and
above, you need to either:
 * update the SDK configuration options in xcode/Config/General.xconfig.
   Comment options SDKROOT, MACOS_DEPLOYMENT_TARGET, and GCC_VERSION. If
   you choose this route you lose the ability to target earlier versions
   of MacOS X.
 * Install an SDK for an earlier version. This doesn't appear to be
   supported by Apple, but has been reported to work
   (http://stackoverflow.com/questions/5378518).

Tweaking Google Test
--------------------

Google Test can be used in diverse environments.  The default
configuration may not work (or may not work well) out of the box in
some environments.  However, you can easily tweak Google Test by
defining control macros on the compiler command line.  Generally,
these macros are named like GTEST_XYZ and you define them to either 1
or 0 to enable or disable a certain feature.

We list the most frequently used macros below.  For a complete list,
see file include/gtest/internal/gtest-port.h.

### Choosing a TR1 Tuple Library ###

Some Google Test features require the C++ Technical Report 1 (TR1)
tuple library, which is not yet available with all compilers.  The
good news is that Google Test implements a subset of TR1 tuple that's
enough for its own need, and will automatically use this when the
compiler doesn't provide TR1 tuple.

Usually you don't need to care about which tuple library Google Test
uses.  However, if your project already uses TR1 tuple, you need to
tell Google Test to use the same TR1 tuple library the rest of your
project uses, or the two tuple implementations will clash.  To do
that, add

  -DGTEST_USE_OWN_TR1_TUPLE=0

to the compiler flags while compiling Google Test and your tests.  If
you want to force Google Test to use its own tuple library, just add

  -DGTEST_USE_OWN_TR1_TUPLE=1

to the compiler flags instead.

If you don't want Google Test to use tuple at all, add

  -DGTEST_HAS_TR1_TUPLE=0

and all features using tuple will be disabled.

### Multi-threaded Tests ###

Google Test is thread-safe where the pthread library is available.
After #include "gtest/gtest.h", you can check the GTEST_IS_THREADSAFE
macro to see whether this is the case (yes if the macro is #defined to
1, no if it's undefined.).

If Google Test doesn't correctly detect whether pthread is available
in your environment, you can force it with

  -DGTEST_HAS_PTHREAD=1

or

  -DGTEST_HAS_PTHREAD=0

When Google Test uses pthread, you may need to add flags to your
compiler and/or linker to select the pthread library, or you'll get
link errors.  If you use the CMake script or the deprecated Autotools
script, this is taken care of for you.  If you use your own build
script, you'll need to read your compiler and linker's manual to
figure out what flags to add.

### As a Shared Library (DLL) ###

Google Test is compact, so most users can build and link it as a
static library for the simplicity.  You can choose to use Google Test
as a shared library (known as a DLL on Windows) if you prefer.

To compile *gtest* as a shared library, add

  -DGTEST_CREATE_SHARED_LIBRARY=1

to the compiler flags.  You'll also need to tell the linker to produce
a shared library instead - consult your linker's manual for how to do
it.

To compile your *tests* that use the gtest shared library, add

  -DGTEST_LINKED_AS_SHARED_LIBRARY=1

to the compiler flags.

Note: while the above steps aren't technically necessary today when
using some compilers (e.g. GCC), they may become necessary in the
future, if we decide to improve the speed of loading the library (see
http://gcc.gnu.org/wiki/Visibility for details).  Therefore you are
recommended to always add the above flags when using Google Test as a
shared library.  Otherwise a future release of Google Test may break
your build script.

### Avoiding Macro Name Clashes ###

In C++, macros don't obey namespaces.  Therefore two libraries that
both define a macro of the same name will clash if you #include both
definitions.  In case a Google Test macro clashes with another
library, you can force Google Test to rename its macro to avoid the
conflict.

Specifically, if both Google Test and some other code define macro
FOO, you can add

  -DGTEST_DONT_DEFINE_FOO=1

to the compiler flags to tell Google Test to change the macro's name
from FOO to GTEST_FOO.  Currently FOO can be FAIL, SUCCEED, or TEST.
For example, with -DGTEST_DONT_DEFINE_TEST=1, you'll need to write

  GTEST_TEST(SomeTest, DoesThis) { ... }

instead of

  TEST(SomeTest, DoesThis) { ... }

in order to define a test.

Upgrating from an Earlier Version
---------------------------------

We strive to keep Google Test releases backward compatible.
Sometimes, though, we have to make some breaking changes for the
users' long-term benefits.  This section describes what you'll need to
do if you are upgrading from an earlier version of Google Test.

### Upgrading from 1.3.0 or Earlier ###

You may need to explicitly enable or disable Google Test's own TR1
tuple library.  See the instructions in section "Choosing a TR1 Tuple
Library".

### Upgrading from 1.4.0 or Earlier ###

The Autotools build script (configure + make) is no longer officially
supportted.  You are encouraged to migrate to your own build system or
use CMake.  If you still need to use Autotools, you can find
instructions in the README file from Google Test 1.4.0.

On platforms where the pthread library is available, Google Test uses
it in order to be thread-safe.  See the "Multi-threaded Tests" section
for what this means to your build script.

If you use Microsoft Visual C++ 7.1 with exceptions disabled, Google
Test will no longer compile.  This should affect very few people, as a
large portion of STL (including <string>) doesn't compile in this mode
anyway.  We decided to stop supporting it in order to greatly simplify
Google Test's implementation.

Developing Google Test
----------------------

This section discusses how to make your own changes to Google Test.

### Testing Google Test Itself ###

To make sure your changes work as intended and don't break existing
functionality, you'll want to compile and run Google Test's own tests.
For that you can use CMake:

  mkdir mybuild
  cd mybuild
  cmake -Dgtest_build_tests=ON ${GTEST_DIR}

Make sure you have Python installed, as some of Google Test's tests
are written in Python.  If the cmake command complains about not being
able to find Python ("Could NOT find PythonInterp (missing:
PYTHON_EXECUTABLE)"), try telling it explicitly where your Python
executable can be found:

  cmake -DPYTHON_EXECUTABLE=path/to/python -Dgtest_build_tests=ON ${GTEST_DIR}

Next, you can build Google Test and all of its own tests.  On *nix,
this is usually done by 'make'.  To run the tests, do

  make test

All tests should pass.

### Regenerating Source Files ###

Some of Google Test's source files are generated from templates (not
in the C++ sense) using a script.  A template file is named FOO.pump,
where FOO is the name of the file it will generate.  For example, the
file include/gtest/internal/gtest-type-util.h.pump is used to generate
gtest-type-util.h in the same directory.

Normally you don't need to worry about regenerating the source files,
unless you need to modify them.  In that case, you should modify the
corresponding .pump files instead and run the pump.py Python script to
regenerate them.  You can find pump.py in the scripts/ directory.
Read the Pump manual [2] for how to use it.

  [2] http://code.google.com/p/googletest/wiki/PumpManual

### Contributing a Patch ###

We welcome patches.  Please read the Google Test developer's guide [3]
for how you can contribute.  In particular, make sure you have signed
the Contributor License Agreement, or we won't be able to accept the
patch.

  [3] http://code.google.com/p/googletest/wiki/GoogleTestDevGuide

Happy testing!