python-testing/08-ci.html at gh-pages · anaisaddad/python-testing

History

170 lines (170 loc) · 9.01 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

<!DOCTYPE html>

<html>

<head>

<title>Software Carpentry: Testing</title>

<!--[if lt IE 9]>

<![endif]-->

</head>

</a>

</div>

<a href="index.html"><h1 class="title">Testing</h1></a>

<h2 class="subtitle">Continuous Integration</h2>

<h2><span class="glyphicon glyphicon-certificate"></span>Learning Objectives</h2>

</div>

<ul>

<li>Understand how continuous integration speeds software development</li>

<li>Understand the benefits of continuous integration</li>

<li>Implement a continuous integration server</li>

<li>Identify a few options for hosting a continuous integration server</li>

</ul>

</div>

</section>

<p>To make running the tests as easy as possible, many software development teams implement a strategy called <strong>continuous integration</strong>. As its name implies, continuous integration integrates the test suite into the development process. Every time a change is made to the repository, the continuous integration system builds and checks that code.</p>

<h2><span class="glyphicon glyphicon-pencil"></span>Thought Experiment: Does Your Software Work on Your Colleague’s Computer?</h2>

</div>

<p>Imagine you developed software on a MacOSX computer. Last week, you helped your office mate build and run it on their Linux computer. You’ve made some changes since then.</p>

<li>How can you be sure it will still work if they update their repository when they come back from vacation?</li>

<li>How long will that process take? machine until you try rebuilding it on their machine.</li>

</ol>

</div>

</section>

<p>The typical story in a research lab is that, well, you don’t know whether it will work on your colleagues’ machine until you try rebuilding it on their machine. If you have a build system, it might take a few minutes to update the repository, rebuild the code, and run the tests. If you don’t have a build system, it could take all afternoon just to see if your new changes are compatible.</p>

<h2><span class="glyphicon glyphicon-pushpin"></span>Let The Computers Do The Work</h2>

</div>

<p>Scientists are good at creative insights, conceptual understanding, critical analysis, and consuming espresso. Computers are good at following instructions. Science would be more fun if the scientists could just give the computers the instructions and go grab an espresso.</p>

<p>Continuous integration servers allow just that. Based on your instructions, a continuous integration server can:</p>

<ul>

<li>check out new code from a repository</li>

<li>spin up instances of supported operating systems (i.e., various versions of OSX, Linux, Windows, etc.).</li>

<li>spin up those instances with different software versions (i.e., python 2.7 and python 3.0)</li>

<li>run the build and test scripts</li>

<li>check for errors</li>

<li>and report the results.</li>

</ul>

</div>

</aside>

<p>Since the first step the server conducts is to check out the code from a repository, we’ll need to put our code online to make use of this kind of server (unless we are able/willing to set up our own CI server).</p>

<h2><span class="glyphicon glyphicon-pencil"></span>Set Up a Mean Git Repository on GitHub</h2>

</div>

<p>Your <code>mean.py</code> <code>test_mean.py</code> files can be the contents of a repository on GitHub.</p>

<li>Go to GitHub and <a href="https://github.com/new">create a repository</a> called mean.</li>

<li>Clone that repository (git clone https://github.com:yourusername/mean)</li>

<li>Copy the <code>mean.py</code> and <code>test_mean.py</code> files into the repository directory.</li>

<li>Use git to <code>add</code>, <code>commit</code>, and <code>push</code> the two files to GitHub.</li>

</ol>

</div>

</section>

<h2 id="giving-instructions">Giving Instructions</h2>

<p>Your work on the mean function has both code and tests. Let’s copy that code into its own repository and add continuous integration to that repository.</p>

<h2><span class="glyphicon glyphicon-pencil"></span>Decide How To Set Up the Server</h2>

</div>

<p>It doesn’t need a build system, because Python does not need to be compiled.</p>

<li>Write the names of the software dependencies in a file called requirements.txt and save the file.</li>

<li>In fact, why don’t you go ahead and version control it?</li>

</ol>

</div>

</section>

<h3 id="travis-ci">Travis-CI</h3>

<p><a href="https://travis-ci.org/">Travis</a> is a continous integration server hosting platform. It’s commonly used in Ruby development circles as well as in the scientific python community.</p>

<h2><span class="glyphicon glyphicon-pushpin"></span>Get a Travis-CI Account</h2>

</div>

<p>To use Travis, all you need is an account. It’s free.</p>

<li>Someone in your group should sign up for a Travis account.</li>

<li>Follow the instructions on the Travis website to connect your Travis account with GitHub.</li>

</ol>

</div>

</aside>

<p>A file called <code>.travis.yml</code> in your repository will signal to Travis that you want to build and test this repository on Travis-CI. Such a file, for our purposes, is very simple:</p>

<pre><code>language: python

python:

- "2.6"

- "2.7"

- "3.2"

- "3.3"

- "3.4"

- "nightly"

# command to install dependencies

install:

- "pip install -r requirements.txt"

# command to run tests

script: nosetests</code></pre>

<p>You can see how the python package manager, pip, will use your requirements.txt file from the previous exercise. That requirements.txt file is a conventional way to list all of the python packages that we need. If we needed nose, numpy, and pymol, the requirements.txt file would look like this:</p>

<pre><code>nose

numpy

pymol</code></pre>

<h2><span class="glyphicon glyphicon-pencil"></span>Add a .travis.yml File</h2>

</div>

<li>Add .travis.yml to your repository</li>

<li>Commit and push it.</li>

<li>Check the situation at <a href="https://travis-ci.org/">your server</a></li>

</ol>

</div>

</section>

<h2 id="continuous-integration-hosting">Continuous Integration Hosting</h2>

<p>We gave the example of Travis because it’s very very simple to spin up. While it is able to run many flavors of Linux, it currently doesn’t support other platforms as well. Depending on your needs, you may consider other services such as:</p>

<ul>

<li><a href="http://buildbot.net/">buildbot</a></li>

<li><a href="http://www.cdash.org/">CDash</a></li>

<li><a href="https://jenkins-ci.org/">Jenkins</a></li>

</ul>

</div>

</article>

<a class="label swc-blue-bg" href="http://software-carpentry.org">Software Carpentry</a>

<a class="label swc-blue-bg" href="https://github.com/swcarpentry/lesson-template">Source</a>

<a class="label swc-blue-bg" href="mailto:[email protected]">Contact</a>

<a class="label swc-blue-bg" href="LICENSE.html">License</a>

</div>

</body>

</html>

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

FilesExpand file tree

08-ci.html

Latest commit

History

08-ci.html

File metadata and controls