Change string representation form IP [ip] to [ip] to accomadate casting ip to string

Signed-off-by: Yuanchun Shen <yuanchu@amazon.com>

Author: yuancu

core/src/main/java/org/opensearch/sql/data/model/ExprIpValue.java

@@ -45,6 +45,7 @@ public boolean equal(ExprValue other) {
 
   @Override
   public String toString() {
+    // used for casting to string
     return value();
   }
 

core/src/test/java/org/opensearch/sql/data/model/ExprIpValueTest.java

@@ -122,12 +122,8 @@ public void testEquals() {
 
   @Test
   public void testToString() {
-    ipv4EqualStrings.forEach(
-        (s) ->
-            assertEquals(String.format("IP %s", ipv4String), ExprValueUtils.ipValue(s).toString()));
-    ipv6EqualStrings.forEach(
-        (s) ->
-            assertEquals(String.format("IP %s", ipv6String), ExprValueUtils.ipValue(s).toString()));
+    ipv4EqualStrings.forEach((s) -> assertEquals(ipv4String, ExprValueUtils.ipValue(s).toString()));
+    ipv6EqualStrings.forEach((s) -> assertEquals(ipv6String, ExprValueUtils.ipValue(s).toString()));
   }
 
   @Test

integ-test/src/test/java/org/opensearch/sql/calcite/remote/CalcitePPLCastFunctionIT.java

@@ -8,6 +8,7 @@
 import static org.opensearch.sql.legacy.TestsConstants.TEST_INDEX_DATATYPE_NONNUMERIC;
 import static org.opensearch.sql.legacy.TestsConstants.TEST_INDEX_DATATYPE_NUMERIC;
 import static org.opensearch.sql.legacy.TestsConstants.TEST_INDEX_STATE_COUNTRY;
+import static org.opensearch.sql.legacy.TestsConstants.TEST_INDEX_WEBLOGS;
 import static org.opensearch.sql.util.MatcherUtils.rows;
 import static org.opensearch.sql.util.MatcherUtils.schema;
 import static org.opensearch.sql.util.MatcherUtils.verifyDataRows;
@@ -177,4 +178,23 @@ public void testCastIntegerToIp() {
     verifyErrorMessageContains(
         t, "Cannot convert INTEGER to IP, only STRING and IP types are supported");
   }
+
+  // Not available in v2
+  @Test
+  public void testCastIpToString() throws IOException {
+    // Test casting ip to string
+    var actual =
+        executeQuery(
+            String.format(
+                "source=%s | eval s = cast(host as STRING) | fields s", TEST_INDEX_WEBLOGS));
+    verifySchema(actual, schema("s", "string"));
+    verifyDataRows(
+        actual,
+        rows("::1"),
+        rows("0.0.0.2"),
+        rows("::3"),
+        rows("1.2.3.4"),
+        rows("1.2.3.5"),
+        rows("::ffff:1234"));
+  }
 }