ESQL: Allow tests to depend on cluster features (elastic#106271)

This allows writing `required_feature:` in a test to skip the test on
versions of elasticsearch that are missing a feature, opting ESQL into
the same versioning as the yaml tests.

x-pack/plugin/esql/qa/server/src/main/java/org/elasticsearch/xpack/esql/qa/rest/EsqlSpecTestCase.java

@@ -132,6 +132,9 @@ public final void test() throws Throwable {
     }
 
     protected void shouldSkipTest(String testName) {
+        for (String feature : testCase.requiredFeatures) {
+            assumeTrue("Test " + testName + " requires " + feature, clusterHasFeature(feature));
+        }
         assumeTrue("Test " + testName + " is not enabled", isEnabled(testName, Version.CURRENT));
     }
 

x-pack/plugin/esql/qa/testFixtures/src/main/resources/string.csv-spec

@@ -299,7 +299,9 @@ emp_no:integer | name:keyword
 ;
 
 // Note: no matches in MV returned
-in#[skip:-8.11.99, reason:Lucene multivalue warning introduced in 8.12 only]
+in
+required_feature: esql.mv_load
+
 from employees | where job_positions in ("Internship", first_name) | keep emp_no, job_positions;
 ignoreOrder:true
 warning:Line 1:24: evaluation of [job_positions in (\"Internship\", first_name)] failed, treating result as null. Only first 20 failures recorded.

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plugin/EsqlFeatures.java

@@ -14,8 +14,13 @@
 import java.util.Map;
 
 public class EsqlFeatures implements FeatureSpecification {
+    private static final NodeFeature MV_LOAD = new NodeFeature("esql.mv_load");
+
     @Override
     public Map<NodeFeature, Version> getHistoricalFeatures() {
-        return Map.of(TransportEsqlStatsAction.ESQL_STATS_FEATURE, Version.V_8_11_0);
+        return Map.ofEntries(
+            Map.entry(TransportEsqlStatsAction.ESQL_STATS_FEATURE, Version.V_8_11_0),
+            Map.entry(MV_LOAD, Version.V_8_12_0)
+        );
     }
 }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/CsvTests.java

@@ -218,6 +218,10 @@ public CsvTests(String fileName, String groupName, String testName, Integer line
 
     public final void test() throws Throwable {
         try {
+            /*
+             * We're intentionally not NodeFeatures here because we expect all
+             * of the features to be supported in this unit test.
+             */
             assumeTrue("Test " + testName + " is not enabled", isEnabled(testName, Version.CURRENT));
             doTest();
         } catch (Throwable th) {

x-pack/plugin/ql/test-fixtures/src/main/java/org/elasticsearch/xpack/ql/CsvSpecReader.java

@@ -30,6 +30,7 @@ public static class CsvSpecParser implements SpecReader.Parser {
         private final StringBuilder earlySchema = new StringBuilder();
         private final StringBuilder query = new StringBuilder();
         private final StringBuilder data = new StringBuilder();
+        private final List<String> requiredFeatures = new ArrayList<>();
         private CsvTestCase testCase;
 
         private CsvSpecParser() {}
@@ -41,13 +42,17 @@ public Object parse(String line) {
                 if (line.startsWith(SCHEMA_PREFIX)) {
                     assertThat("Early schema already declared " + earlySchema, earlySchema.length(), is(0));
                     earlySchema.append(line.substring(SCHEMA_PREFIX.length()).trim());
+                } else if (line.toLowerCase(Locale.ROOT).startsWith("required_feature:")) {
+                    requiredFeatures.add(line.substring("required_feature:".length()).trim());
                 } else {
                     if (line.endsWith(";")) {
                         // pick up the query
                         testCase = new CsvTestCase();
                         query.append(line.substring(0, line.length() - 1).trim());
                         testCase.query = query.toString();
                         testCase.earlySchema = earlySchema.toString();
+                        testCase.requiredFeatures = List.copyOf(requiredFeatures);
+                        requiredFeatures.clear();
                         earlySchema.setLength(0);
                         query.setLength(0);
                     }
@@ -61,9 +66,10 @@ public Object parse(String line) {
             // read the results
             else {
                 // read data
-                if (line.toLowerCase(Locale.ROOT).startsWith("warning:")) {
+                String lower = line.toLowerCase(Locale.ROOT);
+                if (lower.startsWith("warning:")) {
                     testCase.expectedWarnings.add(line.substring("warning:".length()).trim());
-                } else if (line.toLowerCase(Locale.ROOT).startsWith("ignoreorder:")) {
+                } else if (lower.startsWith("ignoreorder:")) {
                     testCase.ignoreOrder = Boolean.parseBoolean(line.substring("ignoreOrder:".length()).trim());
                 } else if (line.startsWith(";")) {
                     testCase.expectedResults = data.toString();
@@ -88,6 +94,7 @@ public static class CsvTestCase {
         public String expectedResults;
         private final List<String> expectedWarnings = new ArrayList<>();
         public boolean ignoreOrder;
+        public List<String> requiredFeatures = List.of();
 
         // The emulated-specific warnings must always trail the non-emulated ones, if these are present. Otherwise, the closing bracket
         // would need to be changed to a less common sequence (like `]#` maybe).