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cut-n-paste more from the README authored by malcolm.wallace@cs.york.ac.uk's avatar malcolm.wallace@cs.york.ac.uk
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......@@ -60,3 +60,480 @@ To run the tests one particular way only (eg. GHCi):
For more details, see below.
# Running the testsuite with a compiler other than GHC
(to be written. The plan is something like:
```wiki
cvs checkout fpconfig
cd fptools
cvs checkout testsuite
autoconf
./configure
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
ways:
```wiki
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:
```wiki
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):
```wiki
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:
```wiki
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).
1. 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
> > > runs.
> >
> > 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.)
1. Edit all.T in the relevant directory and add a line for the test. The line is always of the form
```wiki
test(<name>, <opt-fn>, <test-fn>, <args>)
```
where
> > *\<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
> > > **omit_compiler_types(compilers)** skip this test for certain compilers
> > > **only_compiler_types(compilers)** do this test for certain compilers only
> > > **expect_fail** this test is an expected failure
> > > **expect_fail_for(ways)** expect failure for certain ways
> > > **expect_fail_if_platform(plat)** expect failure on a certain platform
> > > **expect_fail_if_compiler_type(compiler)** expect failure from a certain compiler
> > > **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
> > >
> > > 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
> > >
> > > ```wiki
> > > compose(omit_ways(['opt']), exit_code(3))
> > > ```
> > >
> > >
> > > as the \<opt-fn\> argument. Calls to compose() can of
> > > course be nested.
> > *\<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_and_run
> > >
> > > >
> > > > Compile the program and run it,
> > > > comparing the output against the
> > > > relevant files.
> > >
> > > multimod_compile
> > >
> > > >
> > > > Compile a multi-module program
> > > > (more about multi-module programs
> > > > below).
> > >
> > > multimod_compile_fail
> > >
> > > >
> > > > Compile a multi-module program,
> > > > and expect the compilation to fail
> > > > with error messages in T.stderr
> > >
> > > multimod_compile_and_run
> > >
> > > >
> > > > Compile and run a multi-module
> > > > program.
> > >
> > > run_command
> > >
> > > >
> > > > 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.
> > >
> > > run_command_ignore_output
> > >
> > > >
> > > > Same as run_command, except the output
> > > > (both stdout and stderr) from the
> > > > command is ignored.
> > >
> > > ghci_script
> > >
> > > >
> > > > 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.
> >
> > ```wiki
> > 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
```wiki
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/runtests.py) 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 runtests.py 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/testlib.py.
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 testlib.py. As described above, test() takes four
arguments:
>
> 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 testlib.py 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:
```wiki
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
fail.
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 testlib.py 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:
>
> compile
> compile_fail
> compile_and_run
> multimod_compile
> multimod_compile_fail
> multimod_compile_and_run
> run_command
> run_command_ignore_output
> ghci_script
and obviously others can be defined. The function should return
either 'pass' or 'fail' indicating that the test passed or failed
respectively.