test: check ES|QL SAMPLE capability before running analyzer/parser tests (elastic#127382)

This commit resolves release test failures by checking the ES|QL SAMPLE capability before running the tests.

Author: jan-elastic

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

@@ -3167,6 +3167,8 @@ private boolean isMultiTypeEsField(Expression e) {
     }
 
     public void testRandomSampleProbability() {
+        assumeTrue("requires SAMPLE capability", EsqlCapabilities.Cap.SAMPLE.isEnabled());
+
         var e = expectThrows(VerificationException.class, () -> analyze("FROM test | SAMPLE 1."));
         assertThat(e.getMessage(), containsString("RandomSampling probability must be strictly between 0.0 and 1.0, was [1.0]"));
 

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

@@ -3360,6 +3360,7 @@ public void testInvalidCompletion() {
     }
 
     public void testSample() {
+        assumeTrue("SAMPLE requires corresponding capability", EsqlCapabilities.Cap.SAMPLE.isEnabled());
         expectError("FROM test | SAMPLE .1 2 3", "line 1:25: extraneous input '3' expecting <EOF>");
         expectError("FROM test | SAMPLE .1 \"2\"", "line 1:23: extraneous input '\"2\"' expecting <EOF>");
         expectError("FROM test | SAMPLE 1", "line 1:20: mismatched input '1' expecting {DECIMAL_LITERAL, '+', '-'}");

x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/esql/60_usage.yml

@@ -123,7 +123,7 @@ setup:
   - do: {xpack.usage: {}}
   - match: { esql.available: true }
   - match: { esql.enabled: true }
-  - length: { esql.features: 21 }
+  - length: { esql.features: 22 }
   - set: {esql.features.dissect: dissect_counter}
   - set: {esql.features.drop: drop_counter}
   - set: {esql.features.eval: eval_counter}
@@ -143,6 +143,7 @@ setup:
   - set: {esql.features.lookup: lookup_counter}
   - set: {esql.features.change_point: change_point_counter}
   - set: {esql.features.inlinestats: inlinestats_counter}
+  - set: {esql.features.sample: sample_counter}
   - length: { esql.queries: 3 }
   - set: {esql.queries.rest.total: rest_total_counter}
   - set: {esql.queries.rest.failed: rest_failed_counter}