Expand test api to allow logging of errors during test discovery

Logging is active only during coverage phase and mirrors that used
for exceptions with junit 4 and other frameworks which do not
execute code during discovery.

pitest/src/main/java/org/pitest/coverage/execute/CoverageTestExecutionListener.java

@@ -10,6 +10,7 @@
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import static java.util.concurrent.TimeUnit.NANOSECONDS;
@@ -42,7 +43,12 @@ public void executionStarted(Description description, boolean suppressParallelWa
     }
 
     @Override
-    public void executionFinished(Description description, boolean passed) {
+    public void executionFinished(Description description, boolean passed, Throwable maybeError) {
+
+        if (maybeError != null) {
+            LOG.log(Level.SEVERE, description.toString(), maybeError);
+        }
+
         Long t0 = startTimes.remove(description);
         int executionTime;
         if (t0 == null) {
@@ -70,4 +76,5 @@ public void executionFinished(Description description, boolean passed) {
 
         invokeQueue.recordTestOutcome(description, passed, executionTime);
     }
+
 }

pitest/src/main/java/org/pitest/testapi/NullExecutionListener.java

@@ -7,7 +7,7 @@ public void executionStarted(Description description) {
     }
 
     @Override
-    public void executionFinished(Description description, boolean passed) {
+    public void executionFinished(Description description, boolean passed, Throwable error) {
         //noop
     }
 }

pitest/src/main/java/org/pitest/testapi/TestUnitExecutionListener.java

@@ -20,5 +20,10 @@ default void executionStarted(Description description) {
     default void executionStarted(Description description, boolean suppressParallelWarning) {
         executionStarted(description);
     }
-    void executionFinished(Description description, boolean passed);
+
+    default void executionFinished(Description description, boolean passed) {
+        executionFinished(description, passed, null);
+    }
+
+    void executionFinished(Description description, boolean passed, Throwable error);
 }