Migrate tests to JUnit5

* Use JUnit5 annotations and imports
* Cleanup assertions
* Remove public visibility from test classes and methods

Author: strangelookingnerd

src/test/java/hudson/plugins/jira/JiraBuildActionTest.java

@@ -2,31 +2,29 @@
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.is;
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import hudson.model.Job;
 import hudson.model.Run;
-import org.junit.Rule;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 import org.jvnet.hudson.test.JenkinsRule;
+import org.jvnet.hudson.test.junit.jupiter.WithJenkins;
 import org.jvnet.hudson.test.recipes.LocalData;
 
 /**
  * Place needed resources in src/test/resources
  *
  */
-public class JiraBuildActionTest {
-
-    @Rule
-    public JenkinsRule r = new JenkinsRule();
+class JiraBuildActionTest {
 
     /**
      * Test if existing serialized JiraBuildAction information will be loaded after upgrading jira
      * plugin version to with new JiraBuildAction class version introduced in PR-72.
      */
     @Test
     @LocalData
-    public void binaryCompatibility() {
+    @WithJenkins
+    void binaryCompatibility(JenkinsRule r) throws Exception {
         assertEquals("Jenkins JiraBuildActionTest config", r.jenkins.getSystemMessage());
 
         Job job = r.getInstance().getItemByFullName("/project", Job.class);