Add 'Build Flow Test Aggregator' publisher

Add a new publisher for aggregating test results of downstream jobs in a
Build Flow project.
https://wiki.jenkins-ci.org/display/JENKINS/Build+Flow+Test+Aggregator+Plugin

Change-Id: I88e74fe279f1924fcac010cc8d7a8850fc231269

jenkins_jobs/modules/publishers.py

@@ -1548,6 +1548,25 @@ def aggregate_tests(parser, xml_parent, data):
         'include-failed-builds', False)).lower()
 
 
+def aggregate_flow_tests(parser, xml_parent, data):
+    """yaml: aggregate-flow-tests
+    Aggregate downstream test results in a Build Flow job.
+    Requires the Jenkins `Build Flow Test Aggregator Plugin.
+    <https://wiki.jenkins-ci.org/display/JENKINS/
+    Build+Flow+Test+Aggregator+Plugin>`_
+
+    Example:
+
+    .. literalinclude:: \
+    /../../tests/publishers/fixtures/aggregate-flow-tests.yaml
+       :language: yaml
+
+    """
+    XML.SubElement(xml_parent,
+                   'org.zeroturnaround.jenkins.'
+                   'flowbuildtestaggregator.FlowTestAggregator')
+
+
 def cppcheck(parser, xml_parent, data):
     """yaml: cppcheck
     Cppcheck result publisher

setup.cfg

@@ -115,6 +115,7 @@ jenkins_jobs.metadata =
 jenkins_jobs.notifications =
     http=jenkins_jobs.modules.notifications:http_endpoint
 jenkins_jobs.publishers =
+    aggregate-flow-tests=jenkins_jobs.modules.publishers:aggregate_flow_tests
     aggregate-tests=jenkins_jobs.modules.publishers:aggregate_tests
     archive=jenkins_jobs.modules.publishers:archive
     artifact-deployer=jenkins_jobs.modules.publishers:artifact_deployer

tests/publishers/fixtures/aggregate-flow-tests.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<project>
+    <publishers>
+        <org.zeroturnaround.jenkins.flowbuildtestaggregator.FlowTestAggregator/>
+    </publishers>
+</project>

tests/publishers/fixtures/aggregate-flow-tests.yaml

@@ -0,0 +1,2 @@
+publishers:
+  - aggregate-flow-tests