KAFKA-19127: Integration test for altering and describing streams group configs (apache#19436)

This PR introduces integration tests for verifying
- altering configs
- `describe` output

for a streams group.  The configs have been defined in `KIP-1071`.

Reviewers: Lucas Brutschy <[email protected]>

Author: aliehsaeedii

tools/src/test/java/org/apache/kafka/tools/ConfigCommandIntegrationTest.java

@@ -217,6 +217,46 @@ public void testGroupConfigUpdateUsingKraft() throws Exception {
         verifyGroupConfigUpdate(asList("--group", defaultGroupName, "--alter"));
     }
 
+    @ClusterTest
+    public void testDescribeStreamsGroupConfigs() {
+        Stream<String> command = Stream.concat(quorumArgs(), Stream.of(
+            "--entity-type", "groups",
+            "--entity-name", "group",
+            "--describe", "--all"));
+        String message = captureStandardOut(run(command));
+
+        assertTrue(message.contains("streams.heartbeat.interval.ms=5000 sensitive=false synonyms={DEFAULT_CONFIG:streams.heartbeat.interval.ms=5000}"));
+        assertTrue(message.contains("streams.num.standby.replicas=0 sensitive=false synonyms={DEFAULT_CONFIG:streams.num.standby.replicas=0}"));
+        assertTrue(message.contains("streams.session.timeout.ms=45000 sensitive=false synonyms={DEFAULT_CONFIG:streams.session.timeout.ms=45000}"));
+    }
+
+    @ClusterTest
+    public void testAlterStreamsGroupNumOfStandbyReplicas() {
+        // Verify the initial config
+        Stream<String> command = Stream.concat(quorumArgs(), Stream.of(
+            "--entity-type", "groups",
+            "--entity-name", "group",
+            "--describe", "--all"));
+        String message = captureStandardOut(run(command));
+        assertTrue(message.contains("streams.num.standby.replicas=0"));
+
+        // Alter number of standby replicas
+        command = Stream.concat(quorumArgs(), Stream.of(
+            "--entity-type", "groups",
+            "--entity-name", "group",
+            "--alter", "--add-config", "streams.num.standby.replicas=1"));
+        message = captureStandardOut(run(command));
+        assertEquals("Completed updating config for group group.", message);
+
+        // Verify the updated config
+        command = Stream.concat(quorumArgs(), Stream.of(
+            "--entity-type", "groups",
+            "--entity-name", "group",
+            "--describe"));
+        message = captureStandardOut(run(command));
+        assertTrue(message.contains("streams.num.standby.replicas=1"));
+    }
+
     private void verifyGroupConfigUpdate(List<String> alterOpts) throws Exception {
         try (Admin client = cluster.admin()) {
             // Add config