Testing B2

Table of Contents

• 1. Introduction for users
  • 1.1. Command line options
• 2. Introduction for developers
  • 2.1. Changing the working directory
  • 2.2. Examining the working directory and changing it
  • 2.3. Test result
• 3. Reference documentation
  • 3.1. init(self, arguments="", executable="bjam", match=TestCmd.match_exact, boost_build_path=None, translate_suffixes=True, pass_toolset=True, use_test_config=True, ignore_toolset_requirements=True, workdir="", **keywords)
  • 3.2. set_tree(self, tree_location)
  • 3.3. write(self, name, content)
  • 3.4. copy(self, src, dst)
  • 3.5. touch(self, names)
  • 3.6. run_build_system(self, extra_args="", subdir="", stdout=None, stderr="", status=0, match=None, pass_toolset=None, use_test_config=None, ignore_toolset_requirements=None, expected_duration=None, **kw)
  • 3.7. read(self, name)
  • 3.8. read_and_strip(self, name)
  • 3.9. Methods for declaring expectations
  • 3.10. Methods for ignoring changes
  • 3.11. Methods for explicitly specifying results
  • 3.12. Helper class List

1. Introduction for users

The testing system for B2 is a small set of Python modules and scripts for automatically testing user-observable behavior. It uses components from testing systems of SCons and Subversion, together with some additional functionality.

To run the tests you need to:

1. Get the source tree of B2

2. Have Python 3 installed. Prior versions are no longer compatible.

3. Build the B2 engine.

4. Configure at least one toolset. You can edit site-config.jam or user-config.jam to add new toolsets. Or you can create file test-config.jam in test directory. In this case, site-config.jam and user-config.jam will be ignored for testing.

5. Make sure that in the configuration jam file(s) that you use you generate no console output, ie. with the B2 ECHO rule. Such console output in the configuration jam file(s) will cause a number of tests to automatically fail which would otherwise succeed.

When all is set, you can run all the tests using the test_all.py script or you can run a specific test by starting its Python script directly.

Examples:

./test_all.py
./generators_test.py

or

python3 test_all.py
python3 generators_test.py

If everything is OK, you will see a list of passed tests. Otherwise, a failure will be reported.

1.1. Command line options

Test scripts will use the toolset you configured to be the default or you can specify a specific one on the command line:

python3 test_all.py borland
python3 generators_test.py msvc-7.1

Other test script flags you can specify on the command line are:

--default-bjam

By default the test system will use the Boost Jam executable found built in its default development build location. This option makes it use the default one available on your system, i.e. the one found in the system path.

--preserve

In case of a failed test its working directory will be copied to the "failed_test" directory under the current directory.

--verbose

Makes the test system and the run build system display additional output. Note though that this may cause tests that check the build system output to fail.

2. Introduction for developers

It is suggested that every new functionality come together with tests, and that bugfixes are accompanied by tests. There’s no need to say that tests are good, but two points are extremely important:

• For an interpreted language like Jam, without any static checks, testing is simply the only safeguard we can have.

• Good tests allow us to change internal design much more safely, and we have not gotten everything nailed down yet.

Adding a new test is simple:

1. Go to test/test_all.py and add new test name to the list at the end of the file. Suppose the test name is "hello".

2. Add a new python module, in this example "hello.py", to do the actual testing.

The module, in general will perform these basic actions:

1. Set up the initial working directory state

2. Run the build system and check the results:

   1. generated output,

   2. changes made to the working directory,

   3. new content of the working directory.

3. Add, remove or touch files or change their content and then repeat the previous step until satisfied.

4. Clean up

The "hello.py" module might contain:

from BoostBuild import List

# Create a temporary working directory
t = BoostBuild.Tester()

# Create the needed files
t.write("jamroot.jam", "")
t.write("jamfile.jam", """
exe hello : hello.cpp ;
""")
t.write("hello.cpp", """
int main()
{
    return 0;
}

""")

t.run_build_system()

# First, create a list of three pathnames.
file_list = List("bin/$toolset/debug/") * List("hello.exe hello.obj")
# Second, assert that those files were added as result of the last build system invocation.
t.expect_addition(file_list)

# Invoke the build system once again.
t.run_build_system("clean")
# Check if the files added previously were removed.
t.expect_removal(file_list)

# Remove temporary directories
t.cleanup()

The test directory contains a file "template.py" which can be used as a start for your own tests.

Overview of the most important methods of class Tester follows.

2.1. Changing the working directory

The class Tester creates a temporary directory in its constructor and changes to that directory. It can be modified by calling these methods:

set_tree

sets the content of the working directory to be equal to the content of the specified directory. This method is preferable when directory tree for testing is large.

write

sets the content of file in a working directory. This is optimal if you want to create a directory tree with 3-4 small files.

touch

changes the modification times of a file

2.2. Examining the working directory and changing it

The method read, inherited from the TestCmd class, can be used to read any file in the working directory and check its content. Tester adds another method for tracking changes. Whenever the build system is run (using run_build_system ), the working dir state before and after running is recorded. In addition, difference between the two states — i.e. lists of files that were added, removed, modified or touched — are stored in two member variables - tree_difference and unexpected_difference.

After than, the test author may specify that some change is expected, for example, by calling expect_addition("foo"). This call will check if the file was indeed added, and if so, will remove its name from the list of added files in unexpected_difference. Likewise, it is possible to specify that some changes are not interesting, for example a call to ignore("*.obj") will just remove every file with the ".obj" extension from unexpected_difference.

When test has finished with expectations and ignoring, the member unexpected_difference will contain the list of all changes not yet accounted for. It is possible to assure that this list is empty by calling the expect_nothing_more member function.

2.3. Test result

Any of the expect* methods below will fail the test if the expectation is not met. It is also possible to perform manually arbitrary test and explicitly cause the test to either pass or fail. Ordinary filesystem functions can be used to work with the directory tree. Methods pass_test and fail_test are used to explicitly give the test outcome.

Typically, after test termination, the working directory is erased. See the "--preserve" command line option for information on how to preserve the working directory content for failed tests for debugging purposes.

3. Reference documentation

The test system is composed of class Tester, derived form TestCmd.TestCmd, and helper class List. Tester and List methods are described below.

The documentation frequently refers to filename. In all cases, files are specified in unix style: a sequence of components, separated by "/". This is true on all platforms. In some contexts a list of files is allowed. In those cases any object with a sequence interface is allowed.

3.1. init(self, arguments="", executable="bjam", match=TestCmd.match_exact, boost_build_path=None, translate_suffixes=True, pass_toolset=True, use_test_config=True, ignore_toolset_requirements=True, workdir="", **keywords)

Optional arguments:

arguments

Arguments passed to the run executable.

executable

Name of the executable to invoke.

match

Function to use for comparing actual and expected file contents.

boost_build_path

Boost build path to be passed to the run executable.

translate_suffixes

Whether to update suffixes on the the file names passed from the test script so they match those actually created by the current toolset. For example, static library files are specified by using the .lib suffix but when the gcc toolset is used it actually creates them using the .a suffix.

pass_toolset

Whether the test system should pass the specified toolset to the run executable.

use_test_config

Whether the test system should tell the run executable to read in the test_config.jam configuration file.

ignore_toolset_requirements

Whether the test system should tell the run executable to ignore toolset requirements.

workdir

Indicates an absolute directory where the test will be run from.

Optional arguments inherited from the base class:

description

Test description string displayed in case of a failed test.

subdir

List of subdirectories to automatically create under the working directory. Each subdirectory needs to be specified separately parent coming before its child.

verbose

Flag that may be used to enable more verbose test system output. Note that it does not also enable more verbose build system output like the "--verbose" command line option does.

Effects:

1. Remembers the current working directory in member original_workdir.

2. Determines the location of the executable (b2 by default) and build system files, assuming that the current directory is test. Formulates b2 invocation command, which will include explicit setting for the BOOST_BUILD_PATH variable and arguments passed to this methods, if any. This command will be used by subsequent invocation of run_build_system. Finally, initializes the base class.

3. Changes the current working directory to the temporary working directory created by the base constructor.

4. If you want to run a test in an existing directory, pass it as workdir.

5. Most parameters passed to this constructor function may be overruled for each specific test system run using run_build_system parameters.

3.2. set_tree(self, tree_location)

Effects:

Replaces the content of the current working directory with the content of directory at tree_location. If tree_location is not absolute pathname, it will be treated as relative to self.original_workdir. This methods also explicitly makes the copied files writeable.

3.3. write(self, name, content)

Effects:

Writes the specified content to the file given by name under the temporary working directory. If the file already exists, it is overwritten. Any required directories are automatically created.

3.4. copy(self, src, dst)

Effects:

Equivalent to self.write(self.read(src), dst).

3.5. touch(self, names)

Effects:

Sets the access and modification times for all files in names to the current time. All the elements in names should be relative paths.

3.6. run_build_system(self, extra_args="", subdir="", stdout=None, stderr="", status=0, match=None, pass_toolset=None, use_test_config=None, ignore_toolset_requirements=None, expected_duration=None, **kw)

Effects:

1. Stores the state of the working directory in self.previous_tree.

2. Changes to subdir, if it is specified. It is relative to the original_workdir or the workdir specified in __init.

3. Invokes the b2 executable, passing extra_args to it. The binary should be located under <test_invocation_dir>/../src/engine. This is to make sure tests use the version of b2 build from source.

4. Compares the stdout, stderr and exit status of build system invocation with values to appropriate parameters, if they are not None. If any difference is found, the test fails.

5. If the expected_duration parameter is specified then it represents the maximal allowed time in seconds for the test to run. The test will be marked as failed if its duration is greater than the given expected_duration parameter value.

6. Stores the new state of the working directory in self.tree. Computes the difference between previous and current trees and stores them in variables self.tree_difference and self.unexpected_difference. Both variables are instances of class tree.Trees_different, which have four attributes: added_files, removed_files, modified_files and touched_files. Each is a list of strings.

3.7. read(self, name)

Effects:

Read the specified file and returns it content. Raises an exception is the file is absent.

3.8. read_and_strip(self, name)

Effects:

Read the specified file and returns it content, after removing trailing whitespace from every line. Raises an exception is the file is absent.

Rationale:

Although this method is questionable, there are a lot of cases when b2 or shells it uses insert spaces. It seems that introducing this method is much simpler than dealing with all those cases.

3.9. Methods for declaring expectations

Accordingly to the number of changes kinds that are detected, there are four methods that specify that test author expects a specific change to occur. They check self.unexpected_difference, and if the change is present there, it is removed. Otherwise, test fails.

Each method accepts a list of names. Those names use / path separator on all systems. Additionally, the test system translates suffixes appropriately. For the test to be portable, suffixes should use Windows convention: exe for executables, dll for dynamic libraries and lib for static libraries. Lastly, the string "$toolset" in file names is replaced by the name of tested toolset.

Note	The List helper class might be useful to create lists of names.

Note	The file content can be examined using the TestCmd.read function.

The members are:

• expect_addition

• expect_removal

• expect_modification

• expect_nothing

Note that expect_modification is used to check that a either file content or timestamp has changed. The rationale is that some compilers change content even if sources does not change, and it’s easier to have a method which checks for both content and time changes.

There’s also a member expect_nothing_more, which checks that all the changes are either expected or ignored, in other words that unexpected_difference is empty by now.

Lastly, there’s a method to compare file content with expected content:

expect_content(self, name, content, exact=0)

The method fails the test if the content of file identified by name is different from content. If exact is true, the file content is used as-is, otherwise, two transformations are applied:

• The read_and_strip method is used to read the file, which removes trailing whitespace

• Each backslash in the file content is converted to forward slash.

3.10. Methods for ignoring changes

There are five methods which ignore changes made to the working tree. They silently remove elements from self.unexpected_difference, and don’t generate error if element is not found. They accept shell style wildcard.

The following methods correspond to four kinds of changes:

• ignore_addition(self, wildcard)

• ignore_removal(self, wildcard)

• ignore_modification(self, wildcard)

• ignore_touch(self, wildcard)

The method ignore(self, wildcard) ignores all the changes made to files that match a wildcard.

3.11. Methods for explicitly specifying results

3.11.1. pass_test(self, condition=1)

Warning

At this moment, the method should not be used.

3.11.2. fail_test(self, condition=1)

Effects: Cause the test to fail if condition is true.

3.12. Helper class List

The class has sequence interface and two additional methods.

3.12.1. init(self, string)

Effects: Splits the string on unescaped spaces and tabs. The split components can further be retrieved using standard sequence access.

3.12.2. mul(self, other)

Effects: Returns an List instance, which elements are all possible concatenations of two string, first of which is from self, and second of which is from other.

The class also defines __str__ and __repr__ methods. Finally, there’s __coerce__ method which allows to convert strings to instances of List.

Example:

l = "a b" * List("c d")
for e in l:
    print e

will output:

ac
ad
bc
bd