Commit e3931f38 authored by Ian Lynagh's avatar Ian Lynagh
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Running the test suite against a GHC build
NOTE: you need Python (any version >= 1.5 will probably do) in order
to use the testsuite.
For testsuite documentation, please see:
To run the test suite against stage 1 of a GHC build in the same
source tree:
cd tests/ghc-regress
(from now on, we'll assume that you're in the tests/ghc-regress
To run a fast version of the testsuite, which should complete in under
5 minutes on a fast machine with an optimised GHC build:
make fast
To run the testsuite with the stage2 compiler (this is often what you
want, because GHCi tests will fail with stage1):
make stage=2
To run the test suite against a different GHC, say ghc-5.04:
make TEST_HC=ghc-5.04
To run an individual test or tests (eg. tc054):
make TEST=tc054
(you can also go straight to the directory containing the test and say
'make TEST=tc054' from there, which will save some time).
To run the tests one particular way only (eg. GHCi):
make WAY=ghci
For more details, see below.
Running the testsuite with a compiler other than GHC
(to be written. The plan is something like:
cvs checkout fpconfig
cd fptools
cvs checkout testsuite
cd testsuite
make TEST_HC=nhc98 COMPILER=nhc98
Running individual tests or subdirectories of the testsuite
Most of the subdirectories in the testsuite have a Makefile. In these
subdirectories you can use 'make' to run the test driver in two
make -- run all the tests in the current directory
make accept -- run the tests, accepting the current output
The following variables may be set on the make command line:
TESTS -- specific tests to run
TEST_HC -- compiler to use
EXTRA_HC_OPTS -- extra flags to send to the Haskell compiler
EXTRA_RUNTEST_OPTS -- extra flags to give the test driver
CONFIG -- use a different configuration file
COMPILER -- stem of a different configuration file
-- from the config directory [default: ghc]
WAY -- just this way
The following ways are defined (for GHC, also see the file config/ghc):
normal -- no special options
opt -- -O
optasm -- -O -fasm
prof -- -O -prof -auto-all
profasm -- -O -prof -auto-all -fasm
unreg -- -unreg
ghci -- (run only, not compile) run test under GHCi
extcore -- -fext-core
optextcore -- -O -fext-core
threaded -- -threaded
certain ways are enabled automatically if the GHC build in the local
tree supports them. Ways that are enabled this way are optasm, prof,
profasm, unreg, threaded, and ghci.
Updating tests when the output changes
If the output of a test has changed, but the new output is still
correct, you can automatically update the sample output to match the
new output like so:
make accept TESTS=<test-name>
where <test-name> is the name of the test. In a directory which
contains a single test, or if you want to update *all* the tests in
the current directory, just omit the 'TESTS=<test-name>' part.
Adding a new test
For a test which can be encapsulated in a single source file, follow
these steps:
1. Find the appropriate place for the test. The GHC regression suite
is generally organised in a "white-box" manner: a regression which
originally illustrated a bug in a particular part of the compiler
is placed in the directory for that part. For example, typechecker
regression tests go in the typechecker/ directory, parser tests
go in parser/, and so on.
It's not always possible to find a single best place for a test;
in those cases just pick one which seems reasonable.
Under each main directory may be up to three subdirectories:
- should_compile: tests which need to compile only
- should_fail: tests which should fail to compile
and generate a particular error message
- should_run: tests which should compile, run with
some specific input, and generate a
particular output.
We don't always divide the tests up like this, and it's not
essential to do so (the directory names have no meaning as
far as the test driver is concerned).
2. Having found a suitable place for the test, give the test a name.
Follow the convention for the directory in which you place the
test: for example, in typecheck/should_compile, tests are named
tc001, tc002, and so on. Suppose you name your test T, then
you'll have the following files:
T.hs The source file containing the test
T.stdin (for tests that run, and optional)
A file to feed the test as standard input when it
T.stdout (for tests that run, and optional)
For tests that run, this file is compared against
the standard output generated by the program. If
T.stdout does not exist, then the program must not
generate anything on stdout.
T.stderr (optional) For tests that run, this file is compared
against the standard error generated by the program.
For tests that compile only, this file is compared
against the standard error output of the compiler,
which is normalised to eliminate bogus differences
(eg. absolute pathnames are removed, whitespace
differences are ignored, etc.)
2. Edit all.T in the relevant directory and add a line for the
test. The line is always of the form
test(<name>, <opt-fn>, <test-fn>, <args>)
<name> is the name of the test, in quotes (' or ").
<opt-fn> is a function (i.e. any callable object in Python)
which allows the options for this test to be changed.
There are several pre-defined functions which can be
used in this field:
normal don't change any options from the defaults
skip skip this test
omit_ways(ways) skip this test for certain ways
only_ways(ways) do this test certain ways only
skip this test for certain compilers
do this test for certain compilers only
expect_broken(bug) this test is a expected not to work
due to the indicated trac bug number
expect_broken_for(bug, ways)
As expect_broken, but only for the
indicated ways
expect_broken_if_platform(bug, plat)
As expect_broken, but only for the
specific platform given
expect_broken_if_compiler_type(bug, compiler_type)
As expect_broken, but only for the
given compiler type
set_stdin(file) use a different file for stdin
exit_code(n) expect an exit code of 'n' from the prog
extra_run_opts(opts) pass some extra opts to the prog
no_clean don't clean up after this test
These functions should normally not be used; instead, use the
expect_broken* functions above so that the problem doesn't
get forgotten about, and when we come back to look at the test
later we know whether current behaviour is why we marked it
as expected to fail:
expect_fail this test is an expected failure
expect_fail_for(ways) expect failure for certain ways
expect failure on a certain platform
expect failure from a certain compiler
you can compose two of these functions together by
saying compose(f,g). For example, to expect an exit
code of 3 and omit way 'opt', we could use
compose(omit_ways(['opt']), exit_code(3))
as the <opt-fn> argument. Calls to compose() can of
course be nested, but it is simpler to use the composes
function which takes a list of functions to be composed, e.g.:
composes([omit_ways(['opt']), exit_code(3)])
<test-fn> is a function which describes how the test should be
run, and determines the form of <args>. The possible
values are:
compile Just compile the program, the
compilation should succeed.
compile_fail Just compile the program, the
compilation should fail (error
messages will be in T.stderr).
Compile the program and run it,
comparing the output against the
relevant files.
Compile a multi-module program
(more about multi-module programs
Compile a multi-module program,
and expect the compilation to fail
with error messages in T.stderr
Compile and run a multi-module
Just run an arbitrary command. The
output is checked against T.stdout and
T.stderr, and the stdin and expected
exit code can be changed in the same
way as for compile_and_run.
Same as run_command, except the output
(both stdout and stderr) from the
command is ignored.
Runs the current compiler, passing
--interactive and using the specified
script as standard input.
<args> is a list of arguments to be passed to <test-fn>.
For compile, compile_fail and compile_and_run, <args>
is a list with a single string which contains extra
compiler options with which to run the test. eg.
test(tc001, normal, compile, ['-fglasgow-exts'])
would pass the flag -fglasgow-exts to the compiler
when compiling tc001.
The multimod_ versions of compile and compile_and_run
expect an extra argument on the front of the list: the
name of the top module in the program to be compiled
(usually this will be 'Main').
A multi-module test is straightforward. It usually goes in a
directory of its own (although this isn't essential), and the source
files can be named anything you like. The test must have a name, in
the same way as a single-module test; and the stdin/stdout/stderr
files follow the name of the test as before. In the same directory,
place a file 'test.T' containing a line like
test(multimod001, normal, multimod_compile_and_run, \
[ 'Main', '-fglasgow-exts', '', 0 ])
as described above.
For some examples, take a look in tests/ghc-regress/programs.
The details
The test suite driver is just a set of Python scripts, as are all of
the .T files in the test suite. The driver (driver/ first
searches for all the .T files it can find, and then proceeds to
execute each one, keeping a track of the number of tests run, and
which ones succeeded and failed.
The script takes several options:
--config <file>
<file> is just a file containing Python code which is
executed. The purpose of this option is so that a file
containing settings for the configuration options can
be specified on the command line. Multiple --config options
may be given.
--rootdir <dir>
<dir> is the directory below which to search for .T files
to run.
--output-summary <file>
In addition to dumping the test summary to stdout, also
put it in <file>. (stdout also gets a lot of other output
when running a series of tests, so redirecting it isn't
always the right thing).
--only <test>
Only run tests named <test> (multiple --only options can
be given). Useful for running a single test from a .T file
containing multiple tests.
-e <stmt>
executes the Python statement <stmt> before running any tests.
The main purpose of this option is to allow certain
configuration options to be tweaked from the command line; for
example, the build system adds '-e config.accept=1' to the
command line when 'make accept' is invoked.
Most of the code for running tests is located in driver/
Take a look.
There is a single Python class (TestConfig) containing the global
configuration for the test suite. It contains information such as the
kind of compiler being used, which flags to give it, which platform
we're running on, and so on. The idea is that each platform and
compiler would have its own file containing assignments for elements
of the configuration, which are sourced by passing the appropriate
--config options to the test driver. For example, the GHC
configuration is contained in the file config/ghc.
A .T file can obviously contain arbitrary Python code, but the general
idea is that it contains a sequence of calls to the function test(),
which resides in As described above, test() takes four
test(<name>, <opt-fn>, <test-fn>, <args>)
The function <opt-fn> is allowed to be any Python callable object,
which takes a single argument of type TestOptions. TestOptions is a
class containing options which affect the way that the current test is
run: whether to skip it, whether to expect failure, extra options to
pass to the compiler, etc. (see for the definition of the
TestOptions class). The idea is that the <opt-fn> function modifies
the TestOptions object that it is passed. For example, to expect
failure for a test, we might do this in the .T file:
def fn(opts):
opts.expect = 'fail'
test(test001, fn, compile, [''])
so when fn is called, it sets the instance variable "expect" in the
instance of TestOptions passed as an argument, to the value 'fail'.
This indicates to the test driver that the current test is expected to
Some of these functions, such as the one above, are common, so rather
than forcing every .T file to redefine them, we provide canned
versions. For example, the provided function expect_fail does the
same as fn in the example above. See for all the canned
functions we provide for <opt-fn>.
The argument <test-fn> is a function which performs the test. It
takes three or more arguments:
<test-fn>( <name>, <way>, ... )
where <name> is the name of the test, <way> is the way in which it is
to be run (eg. opt, optasm, prof, etc.), and the rest of the arguments
are constructed from the list <args> in the original call to test().
The following <test-fn>s are provided at the moment:
and obviously others can be defined. The function should return
either 'pass' or 'fail' indicating that the test passed or failed
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