Make embed session selection request-scoped; stop persisting TestingbotTest

Review finding: TestingBotTestEmbed.doIndex stored the selected session in a shared per-action field
that concurrent requests could overwrite (wrong session's media/authHash). Pass the selection through
a request attribute (request-scoped) that show.jelly reads; drop the shared 'tbo' field/getter.

While verifying the render end-to-end, found that persisting the action failed the JEP-200 class
filter ('Refusing to marshal com.testingbot.models.TestingbotTest') — so the embedded-reports feature
could not be saved at all. TestingBotBuildObject's 'test' field is only used in the constructor to
derive environmentName and is never read afterwards, so make it transient. Verified on a running
Jenkins: the action now saves (build.xml contains it) and both the show and index views render.

Author: jochen-testingbot

src/main/java/testingbot/TestingBotBuildObject.java

@@ -11,7 +11,9 @@ public class TestingBotBuildObject implements Serializable {
     private String testName;
     private final boolean isPassed;
     private String authHash;
-    private TestingbotTest test;
+    // Transient: only used in the constructor to derive environmentName, and never read afterwards.
+    // Persisting it would fail the JEP-200 class filter (TestingbotTest is not marshalable) and bloat build.xml.
+    private transient TestingbotTest test;
     private String environmentName;
 
     public TestingBotBuildObject(String sessionId, String className, String testName, boolean isPassed, String authHash, TestingbotTest test) {

src/main/java/testingbot/TestingBotTestEmbed.java

@@ -12,7 +12,6 @@
 public class TestingBotTestEmbed implements RunAction2 {
     private transient Run run;
     private List<TestingBotBuildObject> ids;
-    private TestingBotBuildObject tbo;
 
     public TestingBotTestEmbed(List<TestingBotBuildObject> ids) {
         this.ids = ids;
@@ -52,16 +51,16 @@ public void onLoad(Run<?, ?> run) {
     public void doIndex(StaplerRequest2 req, StaplerResponse2 rsp)
             throws IOException {
         String sessionId = req.getParameter("sessionId");
-        // Reset the selection each request so a subsequent unmatched request does not render a
-        // previously-selected session's media (this action is shared across requests for the run).
         TestingBotBuildObject selected = null;
         for (TestingBotBuildObject candidate : this.ids) {
             if (candidate.getSessionId().equals(sessionId)) {
                 selected = candidate;
                 break;
             }
         }
-        this.tbo = selected;
+        // Pass the selection through the request (this action is shared across concurrent requests,
+        // so a per-instance field would let requests overwrite each other's selected session).
+        req.setAttribute("tbo", selected);
         try {
             req.getView(this, selected != null ? "show.jelly" : "index.jelly").forward(req, rsp);
         } catch (ServletException e) {
@@ -73,10 +72,6 @@ public Run getRun() {
         return run;
     }
 
-    public TestingBotBuildObject getTbo() {
-        return tbo;
-    }
-
     public List<TestingBotBuildObject> getSessionIds() {
         return ids;
     }

src/main/resources/testingbot/TestingBotTestEmbed/show.jelly

@@ -5,11 +5,12 @@
             <st:include page="sidepanel.jelly" it="${it.run}" optional="true" />
         </l:side-panel>
         <l:main-panel>
-            <h1>${it.tbo.testName}</h1>
-            <a href="https://testingbot.com/tests/${it.tbo.sessionId}?auth=${it.tbo.authHash}&amp;ref=jenkins" target="_blank">View on TestingBot</a>
+            <j:set var="tbo" value="${request.getAttribute('tbo')}"/>
+            <h1>${tbo.testName}</h1>
+            <a href="https://testingbot.com/tests/${tbo.sessionId}?auth=${tbo.authHash}&amp;ref=jenkins" target="_blank">View on TestingBot</a>
             <l:ajax>
                 <div>
-                    <iframe src="https://testingbot.com/mini/?id=${it.tbo.sessionId}&amp;auth=${it.tbo.authHash}&amp;ref=jenkins" style="width: 100%; min-height: 100vh; border: none"></iframe>
+                    <iframe src="https://testingbot.com/mini/?id=${tbo.sessionId}&amp;auth=${tbo.authHash}&amp;ref=jenkins" style="width: 100%; min-height: 100vh; border: none"></iframe>
                 </div>
             </l:ajax>
         </l:main-panel>