junit5: Print failure causes

When the command-line summary prints a filtered stack trace for a
failure, it now also prints similarly filtered stack traces for causes.

java/src/com/github/bazel_contrib/contrib_rules_jvm/junit5/CommandLineSummary.java

@@ -47,24 +47,32 @@ public void writeTo(PrintWriter writer) {
  String className = LegacyReportingUtils.getClassName(testPlan, entry.getKey());
 
  writer.printf("%d) %s (%s)%n", count, entry.getKey().getDisplayName(), className);
+ writeFilteredStackTrace(writer, failure.getCause(), className);
 
- Throwable cause = failure.getCause();
-  StackTraceElement[] stackTrace = cause.getStackTrace();
-  // Find the last line in the stacktrace that matches the classname
+ count++;
+ }
+ }
 
- int last = stackTrace.length - 1;
- for (int i = 0; i < stackTrace.length; i++) {
- if (className.equals(stackTrace[i].getClassName())) {
- last = i;
- }
- }
+ private static void writeFilteredStackTrace(
+ PrintWriter writer, Throwable t, String testClassName) {
+ StackTraceElement[] stackTrace = t.getStackTrace();
+ // Find the last line in the stacktrace that matches the classname
 
- writer.println(cause);
- for (int i = 0; i <= last; i++) {
- writer.println("\tat " + stackTrace[i]);
+ int last = stackTrace.length - 1;
+ for (int i = 0; i < stackTrace.length; i++) {
+ if (testClassName.equals(stackTrace[i].getClassName())) {
+ last = i;
  }
+ }
 
- count++;
+ writer.println(t);
+ for (int i = 0; i <= last; i++) {
+ writer.println("\tat " + stackTrace[i]);
+ }
+
+ if (t.getCause() != null) {
+ writer.print("Caused by: ");
+ writeFilteredStackTrace(writer, t.getCause(), testClassName);
  }
  }