ISSUE-2202: smart filters headers test added (#2763)

kafka-ui-api/src/test/java/com/provectus/kafka/ui/emitter/MessageFiltersTest.java

@@ -13,6 +13,7 @@ import java.time.OffsetDateTime;
 import java.time.temporal.ChronoUnit;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.function.Predicate;
 import org.apache.commons.lang3.RandomStringUtils;
 import org.junit.jupiter.api.Nested;
@@ -80,6 +81,13 @@ class MessageFiltersTest {
       assertFalse(f.test(msg().offset(200L)));
     }
 
+    @Test
+    void canCheckHeaders() {
+      var f = groovyScriptFilter("headers.size() == 2 && headers['k1'] == 'v1'");
+      assertTrue(f.test(msg().headers(Map.of("k1", "v1", "k2", "v2"))));
+      assertFalse(f.test(msg().headers(Map.of("k1", "unexpected", "k2", "v2"))));
+    }
+
     @Test
     void canCheckTimestampMs() {
       var ts = OffsetDateTime.now();