add missing stats reset

Author: mtf90

filters/statistics/src/test/java/de/learnlib/filter/statistic/oracle/CounterOracleTest.java

@@ -26,6 +26,7 @@
 import net.automatalib.word.Word;
 import org.mockito.Mockito;
 import org.testng.Assert;
+import org.testng.annotations.BeforeClass;
 import org.testng.annotations.Test;
 
 public class CounterOracleTest {
@@ -37,6 +38,11 @@ public CounterOracleTest() {
         this.oracle = new CounterOracle<Integer, Word<Character>>(Mockito.mock(MembershipOracle.class));
     }
 
+    @BeforeClass
+    public void setUp() {
+        Statistics.getContainer().clear();
+    }
+
     @Test
     public void testInitialState() {
         verifyCounts(0, 0);