A testing system for Boost.Build


Introduction for users
Introduction for developers
Changing the working directory
Examining the working directory and changing it
Test result
Reference documentation
Method __init__
Method set_tree
Method write
Method copy
Method touch
Method run_build_system
Method read
Method read_and_strip
Methods for declaring expectations
Methods for ignoring changes
Methods for explicitly specifying results
Helper class List

Introduction for users

The testing system for Boost.Build is a small set of Python modules and scripts for automatically testing user-obversable behaviour. It uses components from testing systems of Scons and Subverion, together with some additional functionality.

To run the tests you'd need:

  1. Get the source tree of Boost.Build (located at tools/build in Boost)
  2. Have Python installed. Version 2.1 is known to work.
  3. Build Boost.Jam. See $boost_build_root/jam/index.html for instructions.
  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 $boost_build_root/test directory. In this case, site-config.jam and user-config.jam will be ignored for testing.

When all is done, you can run the tests with

python test_all.py

which will use the default toolset, or you can specify toolset on the command line, for example:

python test_all.py borland

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

It is possible to run a specific test, for example:

python generators_test.py

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:

Adding a new test is simple:

  1. Go to $boost_build_root/test/test_all.py and add new test name to the list at the end of file. Suppose the test name is "hello".
  2. Add a new python module, in this example "hello.py", to do actual testing.

The module, in general will perform these basic actions:

  1. Setting the initial working directory state
  2. Running the build system and checking:
    1. generated output,
    2. changes made to the working directory,
    3. new content of the working directory.
  3. Adding, removing or touching files, or changing their content and then repeating the previous step, until satisfied.
  4. Cleaning up

The "hello.py" module might contain:

from BoostBuild import Tester, List

# Create a temporary working directory
t = Tester()

# Create the needed files
t.write("project-root.jam", "")
t.write("Jamfile", """
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 TestBoostBuild follows.

Changing the working directory

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

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. TestBoostBuild adds another method for tracking changes. Whenever build system is run (via run_build_system), the state of working dir 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 -- is 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's possible to specify that some changes are not interesting, for example a call ignore("*.obj") will just remove every files with ".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 expect_nothing_more member function.

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. To debug a failed test, you should add "--preserve" option when invoking test. On failure, the working directory will be copied to "failed_test" directory in the current dir.

Reference documentation

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

The documentation frequently refer 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 that case any object with sequence interface is allowed.

Method __init__(self, workdir='', arguments='', executable='bjam')

Effects:

  1. Remembers the current working directory in member original_workdir.
  2. Determines the location of executable (bjam by default) and build system files, assuming that the current directory is tools/build/test. Formulates jam invocation command, which will include explicit setting for 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 current working dir to the temporary working directory created by the base constructor.
  4. If you want to run a test in a existing directory, pass it to workdir.

Method 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.

Method 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.

Method copy(self, src, dst)

Effects:

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

Method 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.

Method run_build_system(self, subdir='', extra_args='', stdout=None, stderr='', status=0, **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 bjam executable, passing extra_args to it. The binary should be located under <test_invocation_dir>/../jam/src/bin.<platform>. This is to make sure tests use the version of jam build from CVS.
  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. Stores the new state of the working directory in self.tree. Computes the difference between previous and current trees and store 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.

Method read(self, name)

Effects:

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

Method 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:

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

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. Additionaly, 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 TestCmd.read function.

The members are:

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:

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:

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

Methods for explicitly specifying results

Method pass_test(self, condition=1)

At this moment, the method should not be used.

Method fail_test(self, condition=1)

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

Helper class List

The class has sequence interface and two additional methods.

Method __init__(self, string)

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

Method __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
   

Last modified: Mar 11, 2005

© Copyright Vladimir Prus 2002, 2003, 2004, 2005. Permission to copy, use, modify, sell and distribute this document is granted provided this copyright notice appears in all copies. This document is provided ``as is'' without express or implied warranty, and with no claim as to its suitability for any purpose.