swtbot: Print user instructions to enable SLF4J logging

Change-Id: I115be05e8cc9d608e5657826e4ad997ec5dd02f9
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/c/tracecompass/org.eclipse.tracecompass/+/205303
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>

tmf/org.eclipse.tracecompass.tmf.ui.swtbot.tests/META-INF/MANIFEST.MF

@@ -42,7 +42,8 @@ Import-Package: com.google.common.base,
  org.eclipse.tracecompass.testtraces.ctf,
  org.eclipse.tracecompass.tmf.ctf.core.tests.shared,
  org.eclipse.tracecompass.tmf.ctf.core.trace,
- org.slf4j
+ org.slf4j,
+ org.slf4j.helpers
 Export-Package: org.eclipse.tracecompass.tmf.ui.swtbot.tests.parsers.custom;x-internal:=true,
  org.eclipse.tracecompass.tmf.ui.swtbot.tests.perf.views,
  org.eclipse.tracecompass.tmf.ui.swtbot.tests.perspectives;x-internal:=true,

tmf/org.eclipse.tracecompass.tmf.ui.swtbot.tests/shared/org/eclipse/tracecompass/tmf/ui/swtbot/tests/shared/SWTBotUtils.java

@@ -125,8 +125,10 @@
 import org.eclipse.ui.WorkbenchException;
 import org.eclipse.ui.handlers.IHandlerService;
 import org.hamcrest.Matcher;
+import org.slf4j.ILoggerFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.slf4j.helpers.NOPLoggerFactory;
 
 import com.google.common.collect.Lists;
 
@@ -421,6 +423,7 @@ public void run() {
      * Initialize the environment for SWTBot
      */
     public static void initialize() {
+        checkLogger();
         failIfUIThread();
 
         SWTWorkbenchBot bot = new SWTWorkbenchBot();
@@ -495,6 +498,18 @@ private static void printEnvironment() {
         fPrintedEnvironment = true;
     }
 
+    /**
+     * Check if the SLF4J logger is activated
+     */
+    private static void checkLogger() {
+        ILoggerFactory factory = LoggerFactory.getILoggerFactory();
+        if (factory instanceof NOPLoggerFactory) {
+            System.err.println("SLF4J binding not active. To enable logging, set Auto-Start to true");
+            System.err.println("for org.apache.aries.spifly.dynamic.bundle and slf4j.simple in the");
+            System.err.println("Plug-ins tab of your JUnit Plug-in Test's Run/Debug Configuration.");
+        }
+    }
+
     /**
      * If the test is running in the UI thread then fail
      */