Add intersectSize test for SINTERCARD operation in DefaultReactiveSet…

…OperationsIntegrationTests Signed-off-by: Kiminni <imk0980@gmail.com>

src/test/java/org/springframework/data/redis/core/DefaultReactiveSetOperationsIntegrationTests.java

@@ -40,6 +40,7 @@
  *
  * @author Mark Paluch
  * @author Christoph Strobl
+ * @author Mingi Lee
  */
 @ParameterizedClass
 @MethodSource("testParams")
@@ -230,6 +231,39 @@ void intersectAndStore() {
 setOperations.isMember(destKey, shared).as(StepVerifier::create).expectNext(true).verifyComplete();
 }
 
+@Test
+@EnabledOnCommand("SINTERCARD")
+void intersectSize() {
+
+K key = keyFactory.instance();
+K otherKey = keyFactory.instance();
+K thirdKey = keyFactory.instance();
+
+V onlyInKey = valueFactory.instance();
+V shared1 = valueFactory.instance();
+V shared2 = valueFactory.instance();
+V onlyInOtherKey = valueFactory.instance();
+
+setOperations.add(key, onlyInKey, shared1, shared2).as(StepVerifier::create).expectNext(3L).verifyComplete();
+setOperations.add(otherKey, onlyInOtherKey, shared1, shared2).as(StepVerifier::create).expectNext(3L)
+.verifyComplete();
+setOperations.add(thirdKey, shared1).as(StepVerifier::create).expectNext(1L).verifyComplete();
+
+// Test intersectSize(key, otherKey)
+setOperations.intersectSize(key, otherKey).as(StepVerifier::create).expectNext(2L).verifyComplete();
+
+// Test intersectSize(key, Collection)
+setOperations.intersectSize(key, Arrays.asList(otherKey)).as(StepVerifier::create).expectNext(2L).verifyComplete();
+
+// Test intersectSize(Collection) with multiple keys
+setOperations.intersectSize(Arrays.asList(key, otherKey, thirdKey)).as(StepVerifier::create).expectNext(1L)
+.verifyComplete();
+
+// Test with empty intersection
+K emptyKey = keyFactory.instance();
+setOperations.intersectSize(key, emptyKey).as(StepVerifier::create).expectNext(0L).verifyComplete();
+}
+
 @Test // DATAREDIS-602, DATAREDIS-873
 void difference() {