Drop test that locally build docs

In my experience, a very small percentage of the changes actually
introduce Sphinx based documentation.  Say, a feature may be composed
of 10 patches, and at the end of the series, the feature is
documented.

Requiring the documentation to be build all the time takes a toll on
both local and remote systems CI systems.  Let's make the testing
slimmer, and rely on readthedocs.org to tell if any issues are
introduced.

Instead, let's deal with eventual issues before a release is cut.
Signed-off-by: NCleber Rosa <crosa@redhat.com>

examples/testplans/release.json

@@ -3,6 +3,10 @@
     "description": "Test Plan to be performed before a release is cut",
 
     "tests": [
+
+        {"name": "Check status of master branch",
+         "description": "Navigate to:\n\n   https://github.com/avocado-framework/avocado#build-and-quality-status\n\nand make sure that all build and quality services report good indicators"},
+
 	{"name": "Avocado source is sound",
 	 "description": "On your development machine, on a freshen Avocado source to be released, run `$ make check-full`. Expected result: Make command should say OK."},
 

requirements-selftests.txt

 # Avocado test requirements
-# sphinx (doc build test)
-Sphinx==1.7.8
 
 # inspektor (static and style checks)
 pylint==2.3.0

selftests/__init__.py

@@ -78,7 +78,7 @@ def test_suite(base_selftests=True, plugin_selftests=None):
     selftests_dir = os.path.dirname(os.path.abspath(__file__))
     basedir = os.path.dirname(selftests_dir)
     if base_selftests:
-        for section in ('unit', 'functional', 'doc'):
+        for section in ('unit', 'functional'):
             start_dir = os.path.join(selftests_dir, section)
             suite.addTests(loader.discover(start_dir=start_dir,
                                            top_level_dir=basedir))

selftests/doc/test_doc_build.py

-"""
-Build documentation and report whether we had warning/error messages.
-
-This is geared towards documentation build regression testing.
-"""
-import os
-import unittest
-
-from avocado.utils import download
-from avocado.utils import process
-
-from .. import BASEDIR
-
-
-class DocBuildError(Exception):
-    pass
-
-
-def has_no_external_connectivity():
-    """
-    Check condition for building the docs with Sphinx
-
-    Sphinx will attempt to fetch the Python objects inventory during the build
-    process. If for some reason, this test is being run on a machine that can
-    not access that address simply because of network restrictions (or the
-    developer may simply be on a plane) then it's better to SKIP the test than
-    to give a false positive.
-    """
-    try:
-        download.url_open('http://docs.python.org/objects.inv')
-        return False
-    except Exception:
-        return True
-
-
-class DocBuildTest(unittest.TestCase):
-
-    @unittest.skipIf(has_no_external_connectivity(), "No external connectivity")
-    def test_build_docs(self):
-        """
-        Build avocado HTML docs, reporting failures
-        """
-        ignore_list = []
-        failure_lines = []
-        # Disregard bogus warnings due to a bug in older versions of
-        # python-sphinx.
-        ignore_list.append(b'WARNING: toctree contains reference to '
-                           b'nonexisting document u\'api/test/avocado.core\'')
-        ignore_list.append(b'WARNING: toctree contains reference to '
-                           b'nonexisting document u\'api/test/avocado.plugins\'')
-        ignore_list.append(b'WARNING: toctree contains reference to '
-                           b'nonexisting document u\'api/test/avocado.utils\'')
-        doc_dir = os.path.join(BASEDIR, 'docs')
-        process.run('make -C %s clean' % doc_dir)
-        result = process.run('make -C %s html' % doc_dir, ignore_status=True)
-        self.assertFalse(result.exit_status, "Doc build reported non-zero "
-                         "status:\n%s" % result)
-        stdout = result.stdout.splitlines()
-        stderr = result.stderr.splitlines()
-        output_lines = stdout + stderr
-        for line in output_lines:
-            ignore_msg = False
-            for ignore in ignore_list:
-                if ignore in line:
-                    print('Expected warning ignored: %s' % line.decode('utf-8'))
-                    ignore_msg = True
-            if ignore_msg:
-                continue
-            if b'ERROR' in line:
-                failure_lines.append(line)
-            if b'WARNING' in line:
-                failure_lines.append(line)
-        if failure_lines:
-            e_msg = ('%s ERRORS and/or WARNINGS detected while building the html docs:\n' %
-                     len(failure_lines))
-            for (index, failure_line) in enumerate(failure_lines):
-                e_msg += "%s) %s\n" % (index + 1, failure_line)
-            e_msg += ('Full output: %s\n'
-                      % b'\n'.join(output_lines).decode('utf-8'))
-            e_msg += ('Please check the output and fix your '
-                      'docstrings/.rst docs')
-            raise DocBuildError(e_msg)
-
-
-if __name__ == '__main__':
-    unittest.main()