Tests: Add test for merging defaults for a job

Change-Id: I04cd8f080fea7b4cb87182db20ea4d164d6fa267

tests/yamlparser/job_fixtures/concat_defaults003_job.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<project>
+  <actions/>
+  <description>Custom description&lt;!-- Managed by Jenkins Job Builder --&gt;</description>
+  <keepDependencies>false</keepDependencies>
+  <blockBuildWhenDownstreamBuilding>false</blockBuildWhenDownstreamBuilding>
+  <blockBuildWhenUpstreamBuilding>false</blockBuildWhenUpstreamBuilding>
+  <concurrentBuild>false</concurrentBuild>
+  <canRoam>true</canRoam>
+  <properties/>
+  <scm class="hudson.scm.NullSCM"/>
+  <builders>
+    <hudson.tasks.Shell>
+      <command>echo hi</command>
+    </hudson.tasks.Shell>
+  </builders>
+  <publishers/>
+  <buildWrappers/>
+</project>

tests/yamlparser/job_fixtures/concat_defaults003_job.yaml

@@ -0,0 +1,18 @@
+# Global defaults are not used, not merged to custom ones if used from a job.
+
+- defaults:
+    name: global
+    description: 'Global description'
+    concurrent: true
+    wrappers:
+      - timestamps
+
+- defaults:
+    name: custom-defaults
+    description: 'Custom description'
+
+- job:
+    name: sample-job
+    defaults: custom-defaults
+    builders:
+      - shell: echo hi