qemu-iotests: add iotests Python module

Block layer tests that involve QMP commands rather than qemu-img or
qemu-io are not well-suited for shell scripting.  This patch adds a
Python module which allows tests to be written in Python instead.

The basic API is:

  VM          - class for launching and interacting with a VM
  QMPTestCase - abstract base class for tests that use QMP
  qemu_img()  - wrapper function for invoking qemu-img
  qemu_io()   - wrapper function for invoking qemu-io
  imgfmt      - the image format under test (e.g. qcow2, qed)
  test_dir    - scratch directory path for temporary files
  main()      - entry point for running tests

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 164 insertions, 0 deletions

diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
new file mode 100644
index 0000000000..ec1a86a632
--- /dev/null
+++ b/tests/qemu-iotests/iotests.py
@@ -0,0 +1,164 @@
+# Common utilities and Python wrappers for qemu-iotests
+#
+# Copyright (C) 2012 IBM Corp.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import re
+import subprocess
+import unittest
+import sys; sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'QMP'))
+import qmp
+
+__all__ = ['imgfmt', 'imgproto', 'test_dir' 'qemu_img', 'qemu_io',
+           'VM', 'QMPTestCase', 'notrun', 'main']
+
+# This will not work if arguments or path contain spaces but is necessary if we
+# want to support the override options that ./check supports.
+qemu_img_args = os.environ.get('QEMU_IMG', 'qemu-img').split(' ')
+qemu_io_args = os.environ.get('QEMU_IO', 'qemu-io').split(' ')
+qemu_args = os.environ.get('QEMU', 'qemu').split(' ')
+
+imgfmt = os.environ.get('IMGFMT', 'raw')
+imgproto = os.environ.get('IMGPROTO', 'file')
+test_dir = os.environ.get('TEST_DIR', '/var/tmp')
+
+def qemu_img(*args):
+    '''Run qemu-img and return the exit code'''
+    devnull = open('/dev/null', 'r+')
+    return subprocess.call(qemu_img_args + list(args), stdin=devnull, stdout=devnull)
+
+def qemu_io(*args):
+    '''Run qemu-io and return the stdout data'''
+    args = qemu_io_args + list(args)
+    return subprocess.Popen(args, stdout=subprocess.PIPE).communicate()[0]
+
+class VM(object):
+    '''A QEMU VM'''
+
+    def __init__(self):
+        self._monitor_path = os.path.join(test_dir, 'qemu-mon.%d' % os.getpid())
+        self._qemu_log_path = os.path.join(test_dir, 'qemu-log.%d' % os.getpid())
+        self._args = qemu_args + ['-chardev',
+                     'socket,id=mon,path=' + self._monitor_path,
+                     '-mon', 'chardev=mon,mode=control', '-nographic']
+        self._num_drives = 0
+
+    def add_drive(self, path, opts=''):
+        '''Add a virtio-blk drive to the VM'''
+        options = ['if=virtio',
+                   'format=%s' % imgfmt,
+                   'cache=none',
+                   'file=%s' % path,
+                   'id=drive%d' % self._num_drives]
+        if opts:
+            options.append(opts)
+
+        self._args.append('-drive')
+        self._args.append(','.join(options))
+        self._num_drives += 1
+        return self
+
+    def launch(self):
+        '''Launch the VM and establish a QMP connection'''
+        devnull = open('/dev/null', 'rb')
+        qemulog = open(self._qemu_log_path, 'wb')
+        try:
+            self._qmp = qmp.QEMUMonitorProtocol(self._monitor_path, server=True)
+            self._popen = subprocess.Popen(self._args, stdin=devnull, stdout=qemulog,
+                                           stderr=subprocess.STDOUT)
+            self._qmp.accept()
+        except:
+            os.remove(self._monitor_path)
+            raise
+
+    def shutdown(self):
+        '''Terminate the VM and clean up'''
+        self._qmp.cmd('quit')
+        self._popen.wait()
+        os.remove(self._monitor_path)
+        os.remove(self._qemu_log_path)
+
+    def qmp(self, cmd, **args):
+        '''Invoke a QMP command and return the result dict'''
+        return self._qmp.cmd(cmd, args=args)
+
+    def get_qmp_events(self, wait=False):
+        '''Poll for queued QMP events and return a list of dicts'''
+        events = self._qmp.get_events(wait=wait)
+        self._qmp.clear_events()
+        return events
+
+index_re = re.compile(r'([^\[]+)\[([^\]]+)\]')
+
+class QMPTestCase(unittest.TestCase):
+    '''Abstract base class for QMP test cases'''
+
+    def dictpath(self, d, path):
+        '''Traverse a path in a nested dict'''
+        for component in path.split('/'):
+            m = index_re.match(component)
+            if m:
+                component, idx = m.groups()
+                idx = int(idx)
+
+            if not isinstance(d, dict) or component not in d:
+                self.fail('failed path traversal for "%s" in "%s"' % (path, str(d)))
+            d = d[component]
+
+            if m:
+                if not isinstance(d, list):
+                    self.fail('path component "%s" in "%s" is not a list in "%s"' % (component, path, str(d)))
+                try:
+                    d = d[idx]
+                except IndexError:
+                    self.fail('invalid index "%s" in path "%s" in "%s"' % (idx, path, str(d)))
+        return d
+
+    def assert_qmp(self, d, path, value):
+        '''Assert that the value for a specific path in a QMP dict matches'''
+        result = self.dictpath(d, path)
+        self.assertEqual(result, value, 'values not equal "%s" and "%s"' % (str(result), str(value)))
+
+def notrun(reason):
+    '''Skip this test suite'''
+    # Each test in qemu-iotests has a number ("seq")
+    seq = os.path.basename(sys.argv[0])
+
+    open('%s.notrun' % seq, 'wb').write(reason + '\n')
+    print '%s not run: %s' % (seq, reason)
+    sys.exit(0)
+
+def main(supported_fmts=[]):
+    '''Run tests'''
+
+    if supported_fmts and (imgfmt not in supported_fmts):
+        notrun('not suitable for this image format: %s' % imgfmt)
+
+    # We need to filter out the time taken from the output so that qemu-iotest
+    # can reliably diff the results against master output.
+    import StringIO
+    output = StringIO.StringIO()
+
+    class MyTestRunner(unittest.TextTestRunner):
+        def __init__(self, stream=output, descriptions=True, verbosity=1):
+            unittest.TextTestRunner.__init__(self, stream, descriptions, verbosity)
+
+    # unittest.main() will use sys.exit() so expect a SystemExit exception
+    try:
+        unittest.main(testRunner=MyTestRunner)
+    finally:
+        sys.stderr.write(re.sub(r'Ran (\d+) test[s] in [\d.]+s', r'Ran \1 tests', output.getvalue()))