More fixes

Author: svilen-mihaylov-elastic

docs/changelog/121787.yaml

@@ -1,5 +1,5 @@
 pr: 121787
-summary: Initial commit
+summary: Added optional parameters to QSTR ES|QL function
 area: Search
 type: feature
 issues: []

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/fulltext/QueryStringTests.java

@@ -18,11 +18,13 @@
 import org.elasticsearch.xpack.esql.core.type.DataType;
 import org.elasticsearch.xpack.esql.expression.function.FunctionName;
 import org.elasticsearch.xpack.esql.expression.function.TestCaseSupplier;
+import org.elasticsearch.xpack.esql.io.stream.PlanStreamOutput;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Supplier;
 
+import static org.elasticsearch.xpack.esql.SerializationTestUtils.serializeDeserialize;
 import static org.elasticsearch.xpack.esql.core.type.DataType.BOOLEAN;
 import static org.elasticsearch.xpack.esql.core.type.DataType.KEYWORD;
 import static org.elasticsearch.xpack.esql.core.type.DataType.UNSUPPORTED;
@@ -88,8 +90,18 @@ public void testFold() {
         // Query string cannot be folded.
     }
 
+    /**
+     * Copy of the overridden method that doesn't check for children size, as the {@code options} child isn't serialized for Query String.
+     */
     @Override
-    public void testSerializationOfSimple() {
-        // Intentionally not tested here.
+    protected Expression serializeDeserializeExpression(Expression expression) {
+        Expression newExpression = serializeDeserialize(
+            expression,
+            PlanStreamOutput::writeNamedWriteable,
+            in -> in.readNamedWriteable(Expression.class),
+            testCase.getConfiguration() // The configuration query should be == to the source text of the function for this to work
+        );
+        // Fields use synthetic sources, which can't be serialized. So we use the originals instead.
+        return newExpression.replaceChildren(expression.children());
     }
 }