Articles by Alexander Todorov

Do you remember my example of a bad stub design in DNF ? At that time I didn't have a good example of why this is a bad design and what are the consequences of it. Today I have!

From my comment on PR #118

Note: the benefit of this patch are quite subtle. I've played around with creating a few more tests and the benefit I see affect only a few lines of code.

For #114 there doesn't seem to be any need to test _get_query directly, although we call

   q = self.base.sack.query()
   q = q.available()

which will benefit from this PR b/c we're stubbing out the entire Sack object. I will work on a test later today/tomorrow to see how it looks.

OTOH for #113 where we modify _get_query the test can look something like this:

def test_get_query_with_local_rpm(self):
    try:
        (fs, rpm_path) = tempfile.mkstemp('foobar-99.99-1.x86_64.rpm')
        # b/c self.cmd.cli.base is a mock object add_remote_rpm
        # will not update the available packages while testing.
        # it is expected to hit an exception
        with self.assertRaises(dnf.exceptions.PackageNotFoundError):
            self.cmd._get_query(rpm_path)
        self.cmd.cli.base.add_remote_rpm.assert_called_with(rpm_path)
    finally:
        os.remove(rpm_path)

Note the comment above the with block. If we leave out _get_query as before (a simple stub function) we're not going to be able to use assert_called_with later.

Now a more practical example. See commit fe13066 - in case the package is not found we log the error. In case configuration is strict=True then the plugin will raise another exception. With the initial version of the stubs this change in behavior is silently ignored. If there was an error in the newly introduced lines it would go straight into production because the existing tests passed.

What happens is that test_get_packages() calls _get_packages(['notfound']), which is not the real code but a test stub and returns an empty list in this case. The empty list is expected from the test and it will not fail!

With my new stub design the test will execute the actual _get_packages() method from download.py and choke on the exception. The test itself needs to be modified, which is done in commit 2c2b34 and no further errors were found.

So let me summarize: When using mocks, stubs and fake objects we should be replacing external dependencies of the software under test, not internal methods from the SUT!

Posted by Alexander Todorov on Mon 23 November 2015

There are comments.

This is mostly for self reference because it is not currently documented in the code. To use dnf plugins from a local git checkout modify your /etc/dnf/dnf.conf and add the following line under the [main] section:

pluginpath=/path/to/dnf-plugins-core/plugins

Posted by Alexander Todorov on Mon 23 November 2015

There are comments.

Yesterday I've upgraded to Red Hat Enterprise Linux 7.2 on my MacBook Air and I decided to rebuild the wifi and backlight drivers. Wifi broke immediately but I was able to fix the build with a simple patch. I'm now using the newly built kmod-wl-3.10.0-327.el7.x86_64-6.30.223.248-7.el7.x86_64 and it appears to work as expected.

The mba6x_bl driver built without problems however I'm having problems when closing the laptop lid. The screen stays on and (I think) the computer doesn't suspend. My battery was drained as I left the computer as-is overnight. Suspending from the Desktop menu however appears to work. See Issue #41. I'd love to get some help in debugging what's going wrong and trying to fix it. At this point I have no idea where to look and if it's the driver to blame or something else on the system.

UPDATE 2015-11-25: After the upgrade to RHEL 7.2 I also started seeing rhbz#1284851 - Mate power manager doesn't detect AC/DC changes on MacBook Air with RHEL 7.2

Posted by Alexander Todorov on Sat 21 November 2015

There are comments.

In my previous post I briefly talked about running anaconda from a git checkout. My goal was to rewrite tests/gui/ so that they don't use a LiveCD and virtual machines anymore. I'm pleased to announce that this is already done (still not merged), see PR#457.

The majority of the changes are just shuffling bits around and deleting unused code. The existing UI tests were mostly working and only needed minor changes. There are two things which didn't work and are temporarily disabled:

• Clicking the Help button results in rhbz#1282432, which in turn may be hiding another bug behind it;
• Looping over the available languages resulted in AT-SPI NonImplementedError which I'm going to debug next.

To play around with this make sure you have accessibility enabled and:

# cd anaconda/
# export top_srcdir=`pwd`
# setenforce 0
# cd tests/gui/
# ./run_gui_tests.sh

Note: you also need Dogtail for Python3 which isn't officially available yet. I'm building from https://vhumpa.fedorapeople.org/dogtail/beta/dogtail3-0.9.1-0.3.beta3.src.rpm

My future plans are to figure out how to re-enable what is temporarily disabled, update run_gui_tests.sh to properly start gnome-session and enable accessibility, do a better job cleaning up after a failure, enable coverage and hook everything into make ci.

Happy testing!

Posted by Alexander Todorov on Fri 20 November 2015

There are comments.

It is now possible to execute anaconda directly from a git checkout.

Disclaimer: this is only for testing purposes, you are not supposed to execute anaconda from git and install a running system! My intention is to use this feature and rewrite the Dogtail tests inside tests/gui/ which rely on having a LiveCD.iso and running VMs to execute. For me this has proven very slow and difficult to debug problems in the past hence the change.

Note: you will need to have an active DISPLAY in your environment and also set SELinux to permissive, see rhbz#1276376.

Please see PR 438 for more details.

Posted by Alexander Todorov on Fri 13 November 2015

There are comments.

Yesterday I've added Krasimir Tsonev's blog to http://planet.sofiavalley.com and the planet broke. Suddenly it started showing only Krasi's articles and all of them with the same date. The problem was the RSS feed didn't have any timestamps. The fix is trivial:

--- rss.xml.orig    2015-11-13 10:12:35.348625718 +0200
+++ rss.xml 2015-11-13 10:12:45.157932304 +0200
@@ -9,120 +9,160 @@
                             <title><![CDATA[A modern React starter pack based on webpack]]></title>
                             <link>http://krasimirtsonev.com/blog/article/a-modern-react-starter-pack-based-on-webpack</link>
                             <description><![CDATA[<p><i>Checkout React webpack starter in <a href=\"https://github.com/krasimir/react-web<br /><p>You know how crazy is the JavaScript world nowadays. There are new frameworks, libraries and tools coming every day. Frequently I’m exploring some of these goodies. I got a week long holiday. I promised to myself that I’ll not code, read or watch about code. Well, it’s stronger than me. <a href=\"https://github.com/krasimir/react-webpack-starter\">React werbpack starter</a> is the result of my no-programming week.</p>]]></description>
+                            <pubDate>Thu, 01 Oct 2015 00:00:00 +0300</pubDate>
+                            <guid>http://krasimirtsonev.com/blog/article/a-modern-react-starter-pack-based-on-webpack</guid>
                         </item>

Thanks to Krasi for fixing this quickly and happy reading!

Posted by Alexander Todorov on Fri 13 November 2015

There are comments.

Today I wanted to submit a presentation proposal for QA Challenge Accepted 2016 and found a usability problem in their website. The first picture is how the UI looks on my screen. As you can see the screen height is enough to show the first section of the interface. There's something orange at the bottom which isn't clearly identifiable. The next picture shows the UI as it looks after clicking on the PROGRAM menu link.

The problem is that I never saw the orange section, which turned out to be the call for papers and a link to the submission form. To fix this the orange section either needs to go at the top and be clearly visible or at least a new item be added to the menu.

Btw the next event will be in March 2016 in Sofia and I hope to see you there!

Posted by Alexander Todorov on Wed 11 November 2015

There are comments.

This past weekend I've attended OpenFest in Sofia. I have mixed feelings about this year's event. Although I was so tired that I slept through the entire Monday I find some of the presentations not so interesting.

Day One

On the first day I've tried to attend the talk about The Yocto Project by Leon Anavi and Radoslav Kolev. The room was full and I couldn't get in so I watched some of it outside using the live streaming. Next was Building Universal Applications with Angular 2 by Minko Gechev followed by Free And Open Source Software In European Public Administrations by Gijs Hillenius.

Overall impression from these talks was good. They were interesting to me and I liked the way they were presented.

Afterwards I've spend a good hour and more talking to Gijs, catching up on a long overdue email thread about FOSS usage in Bulgarian public administrations. It's always nice to put a face on the email address :). The outcome of this is that I'll have to forward him quite a lot of local contacts. Also my previous article 10 steps to migrate your closed software to open source is now available at OSOR's website.

Day Two

On day two I had quite a few people to talk to but managed to attend couple of presentations. In the main room First Lessons in Control Theory by Hiro Asari and at the end Collaboration In Open Source - How Does It Really Work? by Otto Kekäläinen. I am quite disappointed by both, the challenge level wasn't the one I've expected.

Hiro's subject is interesting but IMO he merely scratched the surface. The first half of the presentation was an introduction in the field and as far as I could tell most of the people left in the room didn't need it. The most interesting part was probably the last 5-10 minutes.

For Otto's presentation I had the expectation it would be interesting stories and failures from working with the community. Instead it was an introduction why and how open source communities work.

That said both presentations are suitable for inexperienced public, folks who are new to open source or IT in general. For folks like me, who have been working for 10 years in the open they weren't so interesting. I'm not against entry-level presentations but at least they have to be properly annotated as such.

The other presentation I've attended on day two was Education 3.0 by Ivan Gospodinov. This was a non-technical talk which conflicted with the lightning talks and I've missed mine. I liked this one though.

General

This year the event was held at a new venue which was a pleasant change. I've heard there were more people attending since previous years yet it seemed there is less seating capacity at the venue.

The after-party however was very good and just before leaving something amazing happened to me. A guy comes to me and asks if I'm atodorov. Obviously I am. Then he says he's my co-worker Vladimir Ralev from Red Hat. Mind you we've talked many times on IRC but not once seen in person.

Posted by Alexander Todorov on Wed 11 November 2015

There are comments.

Anaconda, the Fedora and Red Hat Enterprise Linux installer, has gained some features to facilitate building Docker images. These are only available in kickstart. To build a Docker image for HTTPD, using packages provided in the distro use the following ks.cfg file:

install
lang en_US.UTF-8
keyboard us
network --onboot yes --device eth0 --bootproto dhcp

rootpw  --lock
firewall --disabled
timezone Europe/Sofia

clearpart --all --initlabel
part / --fstype=ext4 --size=1 --grow

bootloader --disabled

%packages --nocore --instLangs=en_US --excludedocs
httpd
-kernel
yum-langpacks # workaround for rhbz#1271766
%end

The above kickstart file will:

• install HTTPD and its dependencies
• disable kernel installation by excluding it from the package list
• disable installation of the boot loader using --disabled. The resulting image will not be bootable
• disable firewall
• locks the root account so it can't login from the console
• prevent installing @core using --nocore
• limit the installation of localization files using --instLangs
• limit the installation of documentation using --excludedocs

Note: the previous --nobase option is deprected and doesn't have any effect.

After the VM installation is complete grab the contents of the root directory:

# virt-tar-out -a /var/lib/libvirt/images/disk.qcow2 / myimage.tar

Import the tarball into Docker and inspect the result:

# docker import myimage.tar local_images:ver1.0
8a2324e6d0e940a998b990262335894a17d261450c33f57dc153d3d1987e4fc1

# docker images
REPOSITORY                                             TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
local_images                                           ver1.0              8a2324e6d0e9        13 seconds ago      320.6 MB
registry.access.redhat.com/rhel                        latest              82ad5fa11820        6 weeks ago         158.3 MB
registry.access.redhat.com/rhscl_beta/httpd-24-rhel7   latest              55a8a150cf2d        9 weeks ago         201.1 MB

Run commands into a new container:

# docker run --name=bash_myimage -it 8a2324e6d0e9 /bin/bash
bash-4.2# cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 7.2 Beta (Maipo)
bash-4.2# rpm -q httpd
httpd-2.4.6-40.el7.x86_64
bash-4.2# exit

# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                      PORTS               NAMES
64f7ca6d5844        8a2324e6d0e9        "/bin/bash"         24 seconds ago      Exited (0) 19 seconds ago                       bash_myimage

As you can see the resulting image is bigger than stock images provided by Red Hat. At this moment I don't know if this is the minimum package set which satisfies dependencies or anaconda adds a bit more on its own. The full package list is given below. There are some packages like device-mapper, dracut, e2fsprogs, iptables, kexec-tools, SELinux related, systemd and tzdata which look out of place. My guess is some of them are pulled in from the various kickstart commands and not really necessary. I will follow up with devel and see if the content can be stripped down even more.

For more information check out these docs:

• Get Started with Docker Formatted Container Images on Red Hat Systems
• Chapter 7. Get Started with Docker Formatted Container Images

Full package list:

acl-2.2.51-12.el7.x86_64
apr-1.4.8-3.el7.x86_64
apr-util-1.5.2-6.el7.x86_64
audit-libs-2.4.1-5.el7.x86_64
basesystem-10.0-7.el7.noarch
bash-4.2.46-19.el7.x86_64
bind-libs-lite-9.9.4-29.el7.x86_64
bind-license-9.9.4-29.el7.noarch
binutils-2.23.52.0.1-54.el7.x86_64
bzip2-libs-1.0.6-13.el7.x86_64
ca-certificates-2015.2.4-71.el7.noarch
chkconfig-1.3.61-5.el7.x86_64
chrony-2.1.1-1.el7.x86_64
coreutils-8.22-15.el7.x86_64
cpio-2.11-24.el7.x86_64
cracklib-2.9.0-11.el7.x86_64
cracklib-dicts-2.9.0-11.el7.x86_64
cryptsetup-libs-1.6.7-1.el7.x86_64
curl-7.29.0-25.el7.x86_64
cyrus-sasl-lib-2.1.26-19.2.el7.x86_64
dbus-1.6.12-13.el7.x86_64
dbus-glib-0.100-7.el7.x86_64
dbus-libs-1.6.12-13.el7.x86_64
dbus-python-1.1.1-9.el7.x86_64
device-mapper-1.02.107-5.el7.x86_64
device-mapper-libs-1.02.107-5.el7.x86_64
dhclient-4.2.5-42.el7.x86_64
dhcp-common-4.2.5-42.el7.x86_64
dhcp-libs-4.2.5-42.el7.x86_64
diffutils-3.3-4.el7.x86_64
dracut-033-358.el7.x86_64
dracut-network-033-358.el7.x86_64
e2fsprogs-1.42.9-7.el7.x86_64
e2fsprogs-libs-1.42.9-7.el7.x86_64
ebtables-2.0.10-13.el7.x86_64
elfutils-libelf-0.163-3.el7.x86_64
elfutils-libs-0.163-3.el7.x86_64
ethtool-3.15-2.el7.x86_64
expat-2.1.0-8.el7.x86_64
file-libs-5.11-31.el7.x86_64
filesystem-3.2-20.el7.x86_64
findutils-4.5.11-5.el7.x86_64
firewalld-0.3.9-14.el7.noarch
gawk-4.0.2-4.el7.x86_64
gdbm-1.10-8.el7.x86_64
glib2-2.42.2-5.el7.x86_64
glibc-2.17-105.el7.x86_64
glibc-common-2.17-105.el7.x86_64
gmp-6.0.0-11.el7.x86_64
gnupg2-2.0.22-3.el7.x86_64
gobject-introspection-1.42.0-1.el7.x86_64
gpgme-1.3.2-5.el7.x86_64
grep-2.20-2.el7.x86_64
gzip-1.5-8.el7.x86_64
hardlink-1.0-19.el7.x86_64
hostname-3.13-3.el7.x86_64
httpd-2.4.6-40.el7.x86_64
httpd-tools-2.4.6-40.el7.x86_64
info-5.1-4.el7.x86_64
initscripts-9.49.30-1.el7.x86_64
iproute-3.10.0-54.el7.x86_64
iptables-1.4.21-16.el7.x86_64
iputils-20121221-7.el7.x86_64
kexec-tools-2.0.7-37.el7.x86_64
keyutils-libs-1.5.8-3.el7.x86_64
kmod-20-5.el7.x86_64
kmod-libs-20-5.el7.x86_64
kpartx-0.4.9-85.el7.x86_64
krb5-libs-1.13.2-10.el7.x86_64
langtable-0.0.31-3.el7.noarch
langtable-data-0.0.31-3.el7.noarch
langtable-python-0.0.31-3.el7.noarch
libacl-2.2.51-12.el7.x86_64
libassuan-2.1.0-3.el7.x86_64
libattr-2.4.46-12.el7.x86_64
libblkid-2.23.2-26.el7.x86_64
libcap-2.22-8.el7.x86_64
libcap-ng-0.7.5-4.el7.x86_64
libcom_err-1.42.9-7.el7.x86_64
libcurl-7.29.0-25.el7.x86_64
libdb-5.3.21-19.el7.x86_64
libdb-utils-5.3.21-19.el7.x86_64
libedit-3.0-12.20121213cvs.el7.x86_64
libffi-3.0.13-16.el7.x86_64
libgcc-4.8.5-4.el7.x86_64
libgcrypt-1.5.3-12.el7_1.1.x86_64
libgpg-error-1.12-3.el7.x86_64
libidn-1.28-4.el7.x86_64
libmnl-1.0.3-7.el7.x86_64
libmount-2.23.2-26.el7.x86_64
libnetfilter_conntrack-1.0.4-2.el7.x86_64
libnfnetlink-1.0.1-4.el7.x86_64
libpwquality-1.2.3-4.el7.x86_64
libselinux-2.2.2-6.el7.x86_64
libselinux-python-2.2.2-6.el7.x86_64
libsemanage-2.1.10-18.el7.x86_64
libsepol-2.1.9-3.el7.x86_64
libss-1.42.9-7.el7.x86_64
libssh2-1.4.3-10.el7.x86_64
libstdc++-4.8.5-4.el7.x86_64
libtasn1-3.8-2.el7.x86_64
libuser-0.60-7.el7_1.x86_64
libutempter-1.1.6-4.el7.x86_64
libuuid-2.23.2-26.el7.x86_64
libverto-0.2.5-4.el7.x86_64
libxml2-2.9.1-5.el7_1.2.x86_64
lua-5.1.4-14.el7.x86_64
lzo-2.06-8.el7.x86_64
mailcap-2.1.41-2.el7.noarch
ncurses-5.9-13.20130511.el7.x86_64
ncurses-base-5.9-13.20130511.el7.noarch
ncurses-libs-5.9-13.20130511.el7.x86_64
nspr-4.10.8-1.el7_1.x86_64
nss-3.19.1-17.el7.x86_64
nss-softokn-3.16.2.3-13.el7_1.x86_64
nss-softokn-freebl-3.16.2.3-13.el7_1.x86_64
nss-sysinit-3.19.1-17.el7.x86_64
nss-tools-3.19.1-17.el7.x86_64
nss-util-3.19.1-3.el7_1.x86_64
openldap-2.4.40-8.el7.x86_64
openssl-libs-1.0.1e-42.el7_1.9.x86_64
p11-kit-0.20.7-3.el7.x86_64
p11-kit-trust-0.20.7-3.el7.x86_64
pam-1.1.8-12.el7_1.1.x86_64
pcre-8.32-15.el7.x86_64
pinentry-0.8.1-14.el7.x86_64
pkgconfig-0.27.1-4.el7.x86_64
popt-1.13-16.el7.x86_64
procps-ng-3.3.10-3.el7.x86_64
pth-2.0.7-23.el7.x86_64
pygobject3-base-3.14.0-3.el7.x86_64
pygpgme-0.3-9.el7.x86_64
pyliblzma-0.5.3-11.el7.x86_64
python-2.7.5-34.el7.x86_64
python-decorator-3.4.0-3.el7.noarch
python-iniparse-0.4-9.el7.noarch
python-libs-2.7.5-34.el7.x86_64
python-pycurl-7.19.0-17.el7.x86_64
python-slip-0.4.0-2.el7.noarch
python-slip-dbus-0.4.0-2.el7.noarch
python-urlgrabber-3.10-7.el7.noarch
pyxattr-0.5.1-5.el7.x86_64
qrencode-libs-3.4.1-3.el7.x86_64
readline-6.2-9.el7.x86_64
redhat-logos-70.0.3-4.el7.noarch
redhat-release-server-7.2-7.el7.x86_64
rpm-4.11.3-17.el7.x86_64
rpm-build-libs-4.11.3-17.el7.x86_64
rpm-libs-4.11.3-17.el7.x86_64
rpm-python-4.11.3-17.el7.x86_64
sed-4.2.2-5.el7.x86_64
setup-2.8.71-6.el7.noarch
shadow-utils-4.1.5.1-18.el7.x86_64
shared-mime-info-1.1-9.el7.x86_64
snappy-1.1.0-3.el7.x86_64
sqlite-3.7.17-8.el7.x86_64
systemd-219-19.el7.x86_64
systemd-libs-219-19.el7.x86_64
sysvinit-tools-2.88-14.dsf.el7.x86_64
tzdata-2015g-1.el7.noarch
ustr-1.0.4-16.el7.x86_64
util-linux-2.23.2-26.el7.x86_64
xz-5.1.2-12alpha.el7.x86_64
xz-libs-5.1.2-12alpha.el7.x86_64
yum-3.4.3-132.el7.noarch
yum-langpacks-0.4.2-4.el7.noarch
yum-metadata-parser-1.1.4-10.el7.x86_64
zlib-1.2.7-15.el7.x86_64

Posted by Alexander Todorov on Wed 28 October 2015

There are comments.

In my previous post I've talked about testing anaconda and friends and raised some questions. Today I'm going to give an example of how to answer one of them: "How different is the code execution path between different tests?"

coverate-tools

I'm going to use coverage-tools in my explanations below so a little introduction is required. All the tools are executable Python scripts which build on top of existing coverage.py API. The difference is mainly in flexibility of parameters and output formatting. I've tried to keep as close as possible to the existing behavior of coverage.py.

coverage-annotate - when given a .coverage data file prints the source code annotated with line numbers and execution markers.

!!! missing/usr/lib64/python2.7/site-packages/pyanaconda/anaconda_argparse.py
>>> covered/usr/lib64/python2.7/site-packages/pyanaconda/anaconda_argparse.py
... skip ...
    37 > import logging
    38 > log = logging.getLogger("anaconda")
    39   
    40   # Help text formatting constants
    41   
    42 > LEFT_PADDING = 8  # the help text will start after 8 spaces
    43 > RIGHT_PADDING = 8  # there will be 8 spaces left on the right
    44 > DEFAULT_HELP_WIDTH = 80
    45   
    46 > def get_help_width():
    47 >     """
    48 >     Try to detect the terminal window width size and use it to
    49 >     compute optimal help text width. If it can't be detected
    50 >     a default values is returned.
    51   
    52 >     :returns: optimal help text width in number of characters
    53 >     :rtype: int
    54 >     """
    55       # don't do terminal size detection on s390, it is not supported
    56       # by its arcane TTY system and only results in cryptic error messages
    57       # ending on the standard output
    58       # (we do the s390 detection here directly to avoid
    59       #  the delay caused by importing the Blivet module
    60       #  just for this single call)
    61 >     is_s390 = os.uname()[4].startswith('s390')
    62 >     if is_s390:
    63 !         return DEFAULT_HELP_WIDTH
    64   
... skip ...

In the example above all lines starting with > were executed by the interpreter. All top-level import statements were executed as you would expect. Then the method get_help_width() was executed (called from somewhere). Because this was on x86_64 machine line 63 was not executed. It is marked with !. The comments and empty lines are of no interest.

coverage-diff - produces git like diff reports on the text output of annotate.

--- a/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/source.py
+++ b/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/source.py
@@ -634,7 +634,7 @@
    634           # Wait to make sure the other threads are done before sending ready, otherwise
    635           # the spoke may not get be sensitive by _handleCompleteness in the hub.
    636 >         while not self.ready:
-   637 !             time.sleep(1)
+   637 >             time.sleep(1)
    638 >         hubQ.send_ready(self.__class__.__name__, False)
    639   
    640 >     def refresh(self):\

In this example line 637 was not executed in the first test run, while it was executed in the second test run. Reading the comments above it is clear the difference between the two test runs is just timing and synchronization.

Kickstart vs. Kickstart

How different is the code execution path between different tests? Looking at Fedora 23 test results we see several tests which differ only slightly in their setup - installation via HTTP, FTP or NFS; installation to SATA, SCSI, SAS drives; installation using RAID for the root file system; These are good candidates for further analysis.

Note: my results below are not from Fedora 23 but the conclusions still apply! The tests were executed on bare metal and virtual machines, trying to use the same hardware or same systems configurations where possible!

Example: HTTP vs. FTP

--- a/usr/lib64/python2.7/site-packages/pyanaconda/packaging/__init__.py
+++ b/usr/lib64/python2.7/site-packages/pyanaconda/packaging/__init__.py
@@ -891,7 +891,7 @@
    891   
    892               # Run any listeners for the new state
    893 >             for func in self._event_listeners[event_id]:
-   894 !                 func()
+   894 >                 func()
    895   
    896 >     def _runThread(self, storage, ksdata, payload, fallback, checkmount):
    897           # This is the thread entry
--- a/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/lib/resize.py
+++ b/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/lib/resize.py
@@ -102,10 +102,10 @@
    102           # Otherwise, fall back on increasingly vague information.
    103 >         if not part.isleaf:
    104 >             return self.storage.devicetree.getChildren(part)[0].name
-   105 >         if getattr(part.format, "label", None):
+   105 !         if getattr(part.format, "label", None):
    106 !             return part.format.label
-   107 >         elif getattr(part.format, "name", None):
-   108 >             return part.format.name
+   107 !         elif getattr(part.format, "name", None):
+   108 !             return part.format.name
    109 !         else:
    110 !             return ""
    111   
@@ -315,10 +315,10 @@
    315 >     def on_key_pressed(self, window, event, *args):
    316           # Handle any keyboard events.  Right now this is just delete for
    317           # removing a partition, but it could include more later.
-   318 >         if not event or event and event.type != Gdk.EventType.KEY_RELEASE:
+   318 !         if not event or event and event.type != Gdk.EventType.KEY_RELEASE:
    319 !             return
    320   
-   321 >         if event.keyval == Gdk.KEY_Delete and self._deleteButton.get_sensitive():
+   321 !         if event.keyval == Gdk.KEY_Delete and self._deleteButton.get_sensitive():
    322 !             self._deleteButton.emit("clicked")
    323   
    324 >     def _sumReclaimableSpace(self, model, path, itr, *args):
--- a/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/source.py
+++ b/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/source.py
@@ -634,7 +634,7 @@
    634           # Wait to make sure the other threads are done before sending ready, otherwise
    635           # the spoke may not get be sensitive by _handleCompleteness in the hub.
    636 >         while not self.ready:
-   637 !             time.sleep(1)
+   637 >             time.sleep(1)
    638 >         hubQ.send_ready(self.__class__.__name__, False)
    639   
    640 >     def refresh(self):

The difference in source.py is from timing/synchronization and can safely be ignored. I'm not exactly sure about __init__.py but doesn't look much of a big deal. We're left with resize.py. The differences in on_key_pressed() are because I've probably used the keyboard instead the mouse (these are indeed manual installs). The other difference is in how the partition labels are displayed. One of the installs was probably using fresh disks while the other not.

Example: SATA vs. SCSI - no difference

Example: SATA vs. SAS (mpt2sas driver)

--- a/usr/lib64/python2.7/site-packages/pyanaconda/bootloader.py
+++ b/usr/lib64/python2.7/site-packages/pyanaconda/bootloader.py
@@ -109,10 +109,10 @@
    109 >     try:
    110 >         opts.parity = arg[idx+0]
    111 >         opts.word   = arg[idx+1]
-   112 !         opts.flow   = arg[idx+2]
-   113 !     except IndexError:
-   114 >         pass
-   115 >     return opts
+   112 >         opts.flow   = arg[idx+2]
+   113 >     except IndexError:
+   114 !         pass
+   115 !     return opts
    116   
    117 ! def _is_on_iscsi(device):
    118 !     """Tells whether a given device is on an iSCSI disk or not."""
@@ -1075,13 +1075,13 @@
   1075 >             command = ["serial"]
   1076 >             s = parse_serial_opt(self.console_options)
   1077 >             if unit and unit != '0':
-  1078 !                 command.append("--unit=%s" % unit)
+  1078 >                 command.append("--unit=%s" % unit)
   1079 >             if s.speed and s.speed != '9600':
   1080 >                 command.append("--speed=%s" % s.speed)
   1081 >             if s.parity:
-  1082 !                 if s.parity == 'o':
+  1082 >                 if s.parity == 'o':
   1083 !                     command.append("--parity=odd")
-  1084 !                 elif s.parity == 'e':
+  1084 >                 elif s.parity == 'e':
   1085 !                     command.append("--parity=even")
   1086 >             if s.word and s.word != '8':
   1087 !                 command.append("--word=%s" % s.word)

As you can see the difference is minimal, mostly related to the underlying hardware. As far as I can tell this has to do with how the bootloader is installed on disk but I'm no expert on this particular piece of code. I've seen the same difference in other comparisons so it probably has to do more with hardware than with what kind of disk/driver is used.

Example: RAID 0 vs. RAID 1 - manual install

--- a/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/datetime_spoke.py
+++ b/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/datetime_spoke.py
@@ -490,9 +490,9 @@
    490   
    491 >         time_init_thread = threadMgr.get(constants.THREAD_TIME_INIT)
    492 >         if time_init_thread is not None:
-   493 >             hubQ.send_message(self.__class__.__name__,
-   494 >                              _("Restoring hardware time..."))
-   495 >             threadMgr.wait(constants.THREAD_TIME_INIT)
+   493 !             hubQ.send_message(self.__class__.__name__,
+   494 !                              _("Restoring hardware time..."))
+   495 !             threadMgr.wait(constants.THREAD_TIME_INIT)
    496   
    497 >         hubQ.send_ready(self.__class__.__name__, False)
    498

As far as I can tell the difference is related to hardware clock settings, probably due to different defaults in BIOS on the various hardware. Additional tests with RAID 5 and RAID 6 reveals the same exact difference. RAID 0 vs. RAID 10 shows no difference at all. Indeed as far as I know anaconda delegates the creation of RAID arrays to mdadm once the desired configuration is known so these results are to be expected.

Conclusion

As you can see sometimes there are tests which appear to be very important but in reality they cover a corner case of the base test. For example if any of the RAID levels works we can be pretty confident all of them work they won't break in anaconda (thanks Adam Williamson)!

What you do with this information is up to you. Sometimes QA is able to execute all the tests and life is good. Sometimes we have to compromise, skip some testing and accept the risks of doing so. Sometimes you can execute all tests for every build, sometimes only once per milestone. Whatever the case having the information to back up your decision is vital!

In my next post on this topic I'm going to talk more about functional tests vs. unit tests. Both anaconda and blivet have both kinds of tests and I'm interested to know if tests from the two categories focus on the same functionality how are they different. If we have a unit test for feature X, does it warrant to spend the resources doing functional testing for X as well?

Posted by Alexander Todorov on Tue 27 October 2015

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My previous post was an introduction to testing installation related components. Now I'm going to talk more about anaconda and how it is tested.

There are two primary ways to test anaconda. You can execute make check in the source directory which will trigger the package test suite. The other possibility is to perform an actual installation, on bare meta or virtual machine, using the latest Rawhide snapshots which also include the latest anaconda. For both of these methods we can collect code coverage information. In live installation mode coverage is enabled via the inst.debug boot argument. Fedora 23 and earlier use debug=1 but that can lead to problems sometimes.

Kickstart Testing

Kickstart is a method of automating the installation of Fedora by supplying the necessary configuration into a text file and pointing the installer at this file. There is the directory tests/kickstart_tests, inside the anaconda source, where each test is a kickstart file and a shell script. The test runner provisions a virtual machine using boot.iso and the kickstart file. A shell script then verifies installation was as expected and copies files of interest to the host system. Kickstart files are also the basis for testing Fedora installations in Beaker.

Naturally some of these in-package kickstart tests are the same as out-of-band kickstart tests. Hint: there are more available but not yet public.

The question which I don't have an answer for right now is "Can we remove some of the duplicates and how this affects devel and QE teams" ? The pros of in-package testing are that it is faster compared to Beaker. The cons are that you're not testing the real distro (every snapshot is a possible final release to the users).

Dogtail

Dogtail uses accessibility technologies to communicate with desktop applications. It is written in Python and can be used as GUI test automation framework. Long time ago I've proposed support for Dogtail in anaconda which was rejected, then couple of years later it was accepted and later removed from the code again.

Anaconda has in-package Dogtail tests (tests/gui/). They work by attaching a second disk image with the test suite to a VM running a LiveCD. Anaconda is started on the LiveCD and an attempt to install Fedora on disk 1 is made. Everything is driven by the Dogtail scripts. There are only a few of these tests available and they are currently disabled. Red Hat QE has also created another method for running Dogtail tests in anaconda using an updates.img with the previous functionality.

Even if there are some duplicate tests I'm not convinced we have to drop the tests/gui/ directory from the code because the framework used to drive the graphical interface of anaconda appears to be very well written. The code is clean and easy to follow. Also I don't have metrics of how much these two methods differ or how much they cover in their testing. IMO they are pretty close and before we can find a way to reliably execute them on a regular basis there isn't much to be done here. One idea is to use the --dirinstall or --image options and skip the LiveCD part entirely.

How Much is Tested

make ci covers 10% of the entire code base for anaconda. Mind you that tests/storage and tests/gui are currently disabled. See PR #346, PR #327 and PR #319! There is definitely room for improvement.

On the other hand live installation testing is much better. Text mode covers around 25% while graphical installations around 40%. Text and graphical combined cover 50% though. These numbers will drop quite a bit once anaconda learns to include all possible files in its report but it is a good estimate.

The important questions to ask here are:

• How much can PyUnit tests cover in anaconda?
• How much can kickstart tests cover ?
• Have we reached a threshold in any of the two primary methods for testing ?
• Does UI automation (with Dogtail) improve anything ?
• When testing a particular feature (say user creation) how different is the code execution path between manual (GUI) testing, kickstart and unit testing ? If not so different can we invest in unit tests instead of higher level tests then ?
• How different is the code execution path between different tests (manual or kickstart) ? In other words how much value are we getting from testing for the resources we're putting in ?

In my next post I will talk more about these questions and some rudimentary analysis against coverage data from the various test methods and test cases!

Posted by Alexander Todorov on Thu 15 October 2015

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Since early 2015 I've been working on testing installation related components in Rawhide. I'm interested in the code produced by the Red Hat Installer Engineering Team and in particular in anaconda, blivet, pyparted and pykickstart. The goal of this effort is to improve the overall testing of these components and also have Red Hat QE contribute some of our knowledge back to the community. The benefit of course will be better software for everyone. In the next several posts I'll summarize what has been done so far and what's to be expected in the future.

Test Documentation Matters

Do you want others to contribute tests? I certainly do! When I started looking at the code it was obviously clear there was no documentation related to testing. Everyone needs to know how to write and execute these tests! Currently we have basic README files describing how to install necessary dependencies for development and test execution, how to execute the tests (and what can be tested) and most importantly what is the test architecture. There is description of how the file structure is organized and which are the base classes to inherit from when adding new tests. Most of the times each component goes through a pylint check and a standard PyUnit test suite.

Test documentation is usually in a tests/README file. For example:

• anaconda
• blivet
• pykickstart
• pyparted

I've tried to explain as much as possible without bloating the files and going into unnecessary details. If you spot something missing please send a pull request.

Continuous Integration

This has been largely an effort driven by Chris Lumens from the devel team. All the components I'm interested in are tested regularly in a CI environment. There is a make ci Makefile target for those of you interested in what exactly gets executed.

Test Coverage

In order to improve something you need to know where you stand. We'll I didn't. That's why the first step was to integrate the coverage.py tool with all of these components.

With the exception of blivet (written in C) all of the other components integrate well with coverage.py and produce good statistics. pykickstart is the champ here with 90% coverage, while anaconda is somewhere between 10% and 50%. Full test coverage measurement for anaconda isn't straight forward and will be the subject of my next post. For the C based code we have to hook up with Gcov which shouldn't be too difficult.

At the moment there are several open pull requests to integrate the coverage test targets with make ci and also report the results in human readable form. I will be collecting these for historical references.

Tools

I've created some basic text-mode coverage-tools to help me combine and compare data from different executions. These are only the start of it and I'm expanding them as my needs for reporting and analytics evolve. I'm also looking into more detailed coverage reports but I don't have enough data and use cases to work on this front at the moment.

Some ideas currently in mind:

• map code changes (git commits) to existing test coverage to get a feeling where to invest in more testing;
• map bugs to code areas and to existing test coverage to see if we aren't missing tests in areas where the bugs are happening;

Bugs

coverage.py is a very nice tool indeed but I guess most people use it in a very limited way. Shortly after I started working with it I've found several places which need improvements. These have to do with combining and reporting on multiple files.

Some of the interesting issues I've found and still open are:

• PR #63 - New option --dont-remove when combining coverage data
• #425 - source parameter not including files which are explicitly specified
• #426 - Difference between coverage results with source specifies full dir instead of module name

In my next post I will talk about anaconda code coverage and what I want to do with it. In the mean time please use the comments to share your feedback.

Posted by Alexander Todorov on Wed 14 October 2015

There are comments.

I've previously written about my Thunderbolt to Ethernet adapter working on Linux despite claims that it should not. Recently I've used my MacBook Air to do a presentation and the Thunderbolt to VGA adapter worked well enough.

It was an Acer adapter but I have no more details b/c it wasn't mine.

Before the event I've tested it and it worked so on the day of the event I've freshly rebooted my laptop to be sure no crashed processes or anything like that was running and gave it a go.

First time I plugged in the MacBook everything worked like a charm. Then my computer was unplugged and the lid closed, causing it to suspend. The second time I've plugged it in I was told there was nothing showing on the projector so I quickly plugged the adapter out and then back in. It worked more or less.

At the time I had LibreOffice Impress in presentation mode but I did see ABRT detecting a kernel problem. When my slides popped up the text on the first one was mostly missing but the rest were ok!

Mind you I'm still running RHEL 7 on my MacBook Air. The above is with kernel-3.10.0-229.14.1.el7.x86_64.

Posted by Alexander Todorov on Wed 30 September 2015

There are comments.

In software testing, usually unit testing, test stubs are programs that simulate the behaviors of external dependencies that a module undergoing the test depends on. Test stubs provide canned answers to calls made during the test.

I've discovered an improperly written stub method in one of DNF's tests:

class DownloadCommandTest(unittest.TestCase):
    def setUp(self):
        def stub_fn(pkg_spec):
            if '.src.rpm' in pkg_spec:
                return Query.filter(sourcerpm=pkg_spec)
            else:
                q = Query.latest()
                return [pkg for pkg in q if pkg_spec == pkg.name]

        cli = mock.MagicMock()
        self.cmd = download.DownloadCommand(cli)
        self.cmd.cli.base.repos = dnf.repodict.RepoDict()

        self.cmd._get_query = stub_fn
        self.cmd._get_query_source = stub_fn

The replaced methods look like this:

    def _get_query(self, pkg_spec):
        """Return a query to match a pkg_spec."""
        subj = dnf.subject.Subject(pkg_spec)
        q = subj.get_best_query(self.base.sack)
        q = q.available()
        q = q.latest()
        if len(q.run()) == 0:
            msg = _("No package " + pkg_spec + " available.")
            raise dnf.exceptions.PackageNotFoundError(msg)
        return q

    def _get_query_source(self, pkg_spec):
        """"Return a query to match a source rpm file name."""
        pkg_spec = pkg_spec[:-4]  # skip the .rpm
        nevra = hawkey.split_nevra(pkg_spec)
        q = self.base.sack.query()
        q = q.available()
        q = q.latest()
        q = q.filter(name=nevra.name, version=nevra.version,
                     release=nevra.release, arch=nevra.arch)
        if len(q.run()) == 0:
            msg = _("No package " + pkg_spec + " available.")
            raise dnf.exceptions.PackageNotFoundError(msg)
        return q

As seen here stub_fn replaces the _get_query methods from the class under test. At the time of writing this has probably seemed like a good idea to speed up writing the tests.

The trouble is we should be replacing the external dependencies of _get_query (other parts of DNF essentially) and not methods from DownloadCommand. To understand why this is a bad idea check PR #113, which directly modifies _get_query. There's no way to test this patch with the current state of the test.

So I took a few days to experiment and update the current test stubs. The result is PR #118. The important bits are the SackStub and SubjectStub classes which hold information about the available RPM packages on the system. The rest are cosmetics to fit around the way the query objects are used (q.available(), q.latest(), q.filter()). The proposed design correctly overrides the external dependencies on dnf.subject.Subject and self.base.sack which are initialized before our plugin is loaded by DNF.

I must say this is the first error of this kind I've seen in my QA practice so far. I have no idea if this was a minor oversight or something which happens more frequently in open source projects but it's a great example nevertheless.

For those of you who'd like to get started on unit testing I can recommend the book The Art of Unit Testing: With Examples in .Net by Roy Osherove!

UPDATE: Part 2 with more practical examples can be found here.

Posted by Alexander Todorov on Fri 25 September 2015

There are comments.

In the last week I've been trying to figure out how many packages conform to the new Harden All Packages policy in Fedora!

From 46884 RPMs, 17385 are 'x86_64' meaning they may contain ELF objects. From them 4489 are reported as failed checksec.

What you should see as the output from checksec is

Full RELRO      Canary found      NX enabled    PIE enabled     No RPATH   No RUNPATH
Full RELRO      Canary found      NX enabled    DSO             No RPATH   No RUNPATH

The first line is for binaries, the second one for libraries b/c DSOs on x86_64 are always position-independent. Some RPATHs are acceptable, e.g. %{_libdir}/foo/ and I've tried to exclude them unless other offenses are found. The script which does this is checksec-collect.

Most often I'm seeing Partial RELRO, No canary found and No PIE errors. Since all packages potentially process untrusted input, it makes sense for all of them to be hardened and enhance the security of Fedora. That's why all of these errors should be considered valid bugs.

Attn package maintainers

Please see if your package is in the list and try to fix it or let me know why it should be excluded, for example it's a boot loader and doesn't function properly with hardening enabled. The full list is available at GitHub.

For more information about the different protection mechanisms see the following links:

• Partial vs Full RELRO
• Stack canaries
• NX memory protection
• Position Independent Executables
• RPATH
• RUNPATH

UPDATE 2015-09-17

I've posted my findings on fedora-devel and the comments are more than interesting even revealing an old bug in libtool.

Posted by Alexander Todorov on Wed 16 September 2015

There are comments.

There's a typo in the Bulgarian translation of Messenger.com. It is highlighted by the red dot on the picture.

hunspell easily catches it so either Facebook doesn't run their translations through a spell checker or their spell checker is borked.

Posted by Alexander Todorov on Thu 20 August 2015

There are comments.

Do you remember the pedometer bug in Samsung Gear Fit I've discovered earlier ? It turns out that Samsung is a fan of this one and has the exact same bug in their S Health application.

The application doesn't block pedometer(e.g. steps counting) while performing other activities such as cycling for example. So in reallity it reports incorrect value for burned callories. At this time I call it bad software development practice/architecture on Samsung's part which leads to this bug being present.

Btw for more interesting bugs see Samsung Gear Fit Bug-of-the-Day.

Posted by Alexander Todorov on Mon 17 August 2015

There are comments.

When editing the grub2 menu (especially in EFI mode) it tells you to press Ctrl-x to save your changes and continue the boot process. However this doesn't work on my MacBook Air, see rhbz#1253637, and maybe some other platforms. If this is the case try pressing F10 instead. It works for me!

Posted by Alexander Todorov on Fri 14 August 2015

There are comments.

If you are working with Python and writing unit tests chances are you are familiar with the coverage reporting tool. However there are testing scenarios in which we either don't use unit tests or maybe execute different code paths(test cases) independent of each other.

For example, this is the case with installation testing in Fedora. Because anaconda - the installer is very complex the easiest way is to test it live, not with unit tests. Even though we can get a coverage report (anaconda is written in Python) it reflects only the test case it was collected from.

coverage combine can be used to combine several data files and produce an aggregate report. This can tell you how much test coverage you have across all your tests.

As far as I can tell Python's coverage doesn't tell you how many times a particular line of code has been executed. It also doesn't tell you which test cases executed a particular line (see PR #59). In the Fedora example, I have the feeling many of our tests are touching the same code base and not contributing that much to the overall test coverage. So I started working on these items.

I imagine a script which will read coverage data from several test executions (preferably in JSON format, PR #60) and produce a graphical report similar to what GitHub does for your commit activity.

See an example here!

The example uses darker colors to indicate more line executions, lighter for less executions. Check the HTML for the actual numbers b/c there are no hints yet. The input JSON files are here and the script to generate the above HTML is at GitHub.

Now I need your ideas and comments!

What kinds of coverage reports are you using in your job ? How do you generate them ? How do they look like ?

Posted by Alexander Todorov on Mon 27 July 2015

There are comments.

Open Data and Intelligent Government is the name of upcoming event organized by Sofia Tech Park on July 14th.

The (preliminary) topics for this event are:

• Government vision for opening data;
• Presentation of national platform for open data;
• Legal aspects of open data;
• Presentation of Bulgarian open data portal;
• Europe and open data;
• Open, coordinated e-government for citizens and business;
• What has already been done by municipalities in Bulgaria;
• Strategy of Sofia municipality for open data;
• Upcoming open data programming contest organized by Sofia municipality.

I will also be participating in this event by covering two topics I'm close to:

• Entrepreneurship and open data - sharing my limited experience with Difio and processing open data;
• Technical tips for successful open data hackathon - sharing my observations as a mentor at HackFMI and giving some recommendations which will help the alleged open data contest make a difference not being just another dull event organized by governmental agencies.

So far other confirmed speakers are Rado from HackBulgaria/ HackFMI and Obshtestvo.bg which are working in the field of open government and open data.

I'm also in touch with the event organizers and helping a little bit with the program. If you're interested in speaking please get in touch with me ASAP.

Posted by Alexander Todorov on Wed 01 July 2015

There are comments.