Fix configuration and source matching in random tests

Author: ivancea

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

@@ -1797,18 +1797,24 @@ public Object extra() {
 
         /**
          * Build a new {@link TestCase} with the {@link #TEST_CONFIGURATION}.
+         * <p>
+         *     The source is also set to match the configuration
+         * </p>
          *
          * @deprecated Use a custom configuration instead, and test the results.
          */
         @Deprecated
         public TestCase withStaticConfiguration() {
-            return withConfiguration(TEST_CONFIGURATION);
+            return withConfiguration(TEST_SOURCE, TEST_CONFIGURATION);
         }
 
         /**
          * Build a new {@link TestCase} with new {@link #configuration}.
+         * <p>
+         *     As the configuration query should match the source, the source is also updated here.
+         * </p>
          */
-        public TestCase withConfiguration(Configuration configuration) {
+        public TestCase withConfiguration(Source source, Configuration configuration) {
             return new TestCase(
                 source,
                 configuration,

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/scalar/AbstractConfigurationFunctionTestCase.java

@@ -29,7 +29,7 @@ protected Expression build(Source source, List<Expression> args) {
     public void testSerializationWithConfiguration() {
         assumeTrue("can't serialize function", canSerialize());
 
-        Configuration config = randomConfiguration();
+        Configuration config = randomConfiguration(testCase.getSource().text(), randomTables());
         Expression expr = buildWithConfiguration(testCase.getSource(), testCase.getDataAsFields(), config);
 
         assertSerialization(expr, config);