📝🚑💩 Add Travis CI badge to docs

Also patch alabaster theme to work around the bug which should be fixed
by merging sphinx-doc/alabaster#147.

docs/_templates/about.html

@@ -0,0 +1,52 @@
+{% if theme_logo %}
+<p class="logo">
+  <a href="{{ pathto(master_doc) }}">
+    <img class="logo" src="{{ pathto('_static/' ~ theme_logo, 1) }}" alt="Logo"/>
+    {% if theme_logo_name|lower == 'true' %}
+    <h1 class="logo logo-name">{{ project }}</h1>
+    {% endif %}
+  </a>
+</p>
+{% else %}
+<h1 class="logo"><a href="{{ pathto(master_doc) }}">{{ project }}</a></h1>
+{% endif %}
+
+{% if theme_description %}
+<p class="blurb">{{ theme_description }}</p>
+{% endif %}
+
+{% if theme_github_user and theme_github_repo %}
+{% if theme_github_button|lower == 'true' %}
+<p>
+<iframe src="https://ghbtns.com/github-btn.html?user={{ theme_github_user }}&repo={{ theme_github_repo }}&type={{ theme_github_type }}&count={{ theme_github_count }}&size=large&v=2"
+  allowtransparency="true" frameborder="0" scrolling="0" width="200px" height="35px"></iframe>
+</p>
+{% endif %}
+{% endif %}
+
+{% if theme_travis_button|lower != 'false' %}
+<p>
+<a class="badge" href="{{ theme_travis_build_url }}">
+    <img
+        alt="Travis CI build badge"
+        src="{{ theme_travis_badge_url }}"
+    />
+</a>
+</p>
+{% endif %}
+
+{% if theme_codecov_button|lower != 'false' %}
+{% if theme_codecov_button|lower == 'true' %}
+    {% set path = theme_github_user + '/' + theme_github_repo %}
+{% else %}
+    {% set path = theme_codecov_button %}
+{% endif %}
+<p>
+<a class="badge" href="https://codecov.io/github/{{ path }}">
+    <img
+    alt="https://codecov.io/github/{{ path }}/coverage.svg?branch={{ theme_badge_branch }}"
+    src="https://codecov.io/github/{{ path }}/coverage.svg?branch={{ theme_badge_branch }}"
+    />
+</a>
+</p>
+{% endif %}

docs/conf.py

@@ -155,6 +155,8 @@ def get_github_data(project_urls):
     'github_repo': PRJ_GITHUB_REPO,
     'github_type': 'star',
     'github_banner': True,
+    'travis_button': True,
+    # 'travis_tld': 'com',
     'show_relbars': True,
     'show_related': True,
     'extra_nav_links': {
@@ -275,3 +277,34 @@ def get_github_data(project_urls):
 
 # If true, `todo` and `todoList` produce output, else they produce nothing.
 todo_include_todos = True
+
+
+# Patch alabaster theme
+# Ref: https://github.com/bitprophet/alabaster/pull/147
+# FIXME: drop this hack once the PR is merged & released; pylint: disable=fixme
+def set_up_travis_context(
+        app, pagename, templatename,  # pylint: disable=unused-argument
+        context,
+        doctree,  # pylint: disable=unused-argument
+):
+    """Add complete Travis URLs to Jinja2 context."""
+    github_slug = '/'.join(
+        (context['theme_github_user'], context['theme_github_repo']),
+    )
+
+    travis_button = str(context['theme_travis_button']).lower()
+    travis_button_enabled = travis_button == 'true'
+
+    travis_slug = github_slug if travis_button_enabled else travis_button
+
+    travis_tld = 'com'  # context["theme_travis_tld"].strip(".").lower()
+    travis_base_uri = 'travis-ci.{}/{}'.format(travis_tld, travis_slug)
+    context['theme_travis_build_url'] = 'https://{}'.format(travis_base_uri)
+    context['theme_travis_badge_url'] = 'https://api.{}.svg?branch={}'.format(
+        travis_base_uri, context['theme_badge_branch'],
+    )
+
+
+def setup(app):
+    """Patch the sphinx theme set up stage."""
+    app.connect('html-page-context', set_up_travis_context)