filters: try to address some of the flaky tests on windows

Author: mtf90

filters/statistics/src/main/java/de/learnlib/filter/statistic/container/MapStatisticsService.java

@@ -83,10 +83,10 @@ public void clear() {
     public String print() {
 
         final StringBuilder sb = new StringBuilder(125);
-        sb.append("Statistics:")
-          .append(System.lineSeparator())
-          .append("============================================")
-          .append(System.lineSeparator());
+        sb.append("""
+                          Statistics:
+                          ============================================
+                          """);
 
         final ReadLock lock = this.lock.readLock();
         lock.lock();
@@ -103,20 +103,16 @@ public String print() {
                     sb.append(": ").append(map.values().iterator().next());
                 } else {
                     for (Entry<Integer, StatisticContainer> e2 : map.entrySet()) {
-                        sb.append(System.lineSeparator())
-                          .append("  * Instance ")
-                          .append(e2.getKey())
-                          .append(": ")
-                          .append(e2.getValue());
+                        sb.append("\n  * Instance ").append(e2.getKey()).append(": ").append(e2.getValue());
                     }
                 }
-                sb.append(System.lineSeparator());
+                sb.append('\n');
             }
         } finally {
             lock.unlock();
         }
 
-        sb.append("============================================").append(System.lineSeparator());
+        sb.append("============================================\n");
 
         return sb.toString();
     }
@@ -343,7 +339,8 @@ private <T> Optional<T> getData(StatisticsKey key,
                 LOGGER.debug("Key '{}' has been written by objects '{}', aggregating ...", key, stats.keySet());
             }
 
-            @NonNull T result = initialValue;
+            @NonNull
+            T result = initialValue;
             boolean written = false;
 
             for (StatisticContainer container : stats.values()) {

filters/statistics/src/test/java/de/learnlib/filter/statistic/MapStatisticsServiceTest.java

@@ -152,19 +152,19 @@ public void testAggregationClock() {
         final Duration c11 = tester.getClock(key1, owner1).orElseThrow();
         final Duration c12 = tester.getClock(key1, owner2).orElseThrow();
 
-        Assert.assertTrue(c11.getNano() > 0);
-        Assert.assertTrue(c12.getNano() > 0);
+        Assert.assertTrue(c11.compareTo(Duration.ZERO) > 0);
+        Assert.assertTrue(c12.compareTo(Duration.ZERO) > 0);
         Assert.assertEquals(tester.getClock(key1).orElseThrow(), c11.plus(c12));
 
         final Duration c21 = tester.getClock(key2, owner1).orElseThrow();
         final Duration c32 = tester.getClock(key3, owner2).orElseThrow();
 
-        Assert.assertTrue(c21.getNano() > 0);
-        Assert.assertTrue(c32.getNano() > 0);
+        Assert.assertTrue(c21.compareTo(Duration.ZERO) > 0);
+        Assert.assertTrue(c32.compareTo(Duration.ZERO) > 0);
         Assert.assertEquals(tester.getClock(key2, owner1).orElseThrow(), c21);
         Assert.assertEquals(tester.getClock(key3, owner2).orElseThrow(), c32);
 
-        Assert.assertEquals(new HashSet<>(tester.getClocks(key1).values()), Set.of(c11, c12));
+        Assert.assertEquals(new HashSet<>(tester.getClocks(key1).values()), new HashSet<>(Arrays.asList(c11, c12)));
         Assert.assertEquals(tester.getClocks(key2).values(), Collections.singleton(c21));
         Assert.assertEquals(tester.getClocks(key3).values(), Collections.singleton(c32));
 
@@ -265,15 +265,15 @@ public void testInsertRetrievalClock() {
         Assert.assertEquals(statistics.getClock(KEY_CLOCK).orElseThrow(), Duration.ZERO);
 
         statistics.pauseClock(KEY_CLOCK);
-        final long nanos1 = statistics.getClock(KEY_CLOCK).orElseThrow().toNanos();
-        Assert.assertTrue(nanos1 > 0L);
+        Duration c1 = statistics.getClock(KEY_CLOCK).orElseThrow();
+        Assert.assertTrue(c1.compareTo(Duration.ZERO) > 0);
 
         statistics.startOrResumeClock(KEY_CLOCK);
         Assert.assertTrue(statistics.getClock(KEY_CLOCK).isPresent());
 
         statistics.pauseClock(KEY_CLOCK);
-        final long nanos2 = statistics.getClock(KEY_CLOCK).orElseThrow().toNanos();
-        Assert.assertTrue(nanos2 > nanos1);
+        Duration c2 = statistics.getClock(KEY_CLOCK).orElseThrow();
+        Assert.assertTrue(c2.compareTo(c1) > 0);
 
         Assert.assertTrue(statistics.getText(KEY_TEXT).isEmpty());
         Assert.assertTrue(statistics.getFlag(KEY_FLAG).isEmpty());
@@ -444,6 +444,7 @@ public void testDisplay() {
                                                   ============================================
                                                   """);
 
-        Assert.assertTrue(pattern.matcher(statistics.print()).matches());
+        String output = statistics.print();
+        Assert.assertTrue(pattern.matcher(output).matches(), output);
     }
 }