Add basic csv tests.

Author: afoucret

x-pack/plugin/esql/qa/testFixtures/src/main/java/org/elasticsearch/xpack/esql/CsvTestsDataLoader.java

@@ -393,6 +393,10 @@ public static void createInferenceEndpoints(RestClient client) throws IOExceptio
             createSparseEmbeddingInferenceEndpoint(client);
         }
 
+        if (clusterHasDenseEmbeddingInferenceEndpoint(client) == false) {
+            createDenseEmbeddingInferenceEndpoint(client);
+        }
+
         if (clusterHasRerankInferenceEndpoint(client) == false) {
             createRerankInferenceEndpoint(client);
         }
@@ -404,6 +408,7 @@ public static void createInferenceEndpoints(RestClient client) throws IOExceptio
 
     public static void deleteInferenceEndpoints(RestClient client) throws IOException {
         deleteSparseEmbeddingInferenceEndpoint(client);
+        deleteDenseEmbeddingInferenceEndpoint(client);
         deleteRerankInferenceEndpoint(client);
         deleteCompletionInferenceEndpoint(client);
     }
@@ -427,6 +432,24 @@ public static boolean clusterHasSparseEmbeddingInferenceEndpoint(RestClient clie
         return clusterHasInferenceEndpoint(client, TaskType.SPARSE_EMBEDDING, "test_sparse_inference");
     }
 
+    public static void createDenseEmbeddingInferenceEndpoint(RestClient client) throws IOException {
+        createInferenceEndpoint(client, TaskType.TEXT_EMBEDDING, "test_dense_inference", """
+                  {
+                   "service": "text_embedding_test_service",
+                   "service_settings": { "model": "my_model", "api_key": "abc64", "dimensions": 10 },
+                   "task_settings": { }
+                 }
+            """);
+    }
+
+    public static void deleteDenseEmbeddingInferenceEndpoint(RestClient client) throws IOException {
+        deleteInferenceEndpoint(client, "test_dense_inference");
+    }
+
+    public static boolean clusterHasDenseEmbeddingInferenceEndpoint(RestClient client) throws IOException {
+        return clusterHasInferenceEndpoint(client, TaskType.TEXT_EMBEDDING, "test_dense_inference");
+    }
+
     public static void createRerankInferenceEndpoint(RestClient client) throws IOException {
         createInferenceEndpoint(client, TaskType.RERANK, "test_reranker", """
             {

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

@@ -0,0 +1,15 @@
+// Note:
+// The "test_completion" service returns the prompt in uppercase, making the output easy to guess.
+ 
+
+completion using a ROW source operator
+required_capability: text_embedding_function
+required_capability: dense_vector_field_type
+
+ROW input="Who is Victor Hugo?"
+| EVAL embedding = TEXT_EMBEDDING("Who is Victor Hugo?", "test_dense_inference")
+;
+
+input:keyword       | embedding:dense_vector
+Who is Victor Hugo? | [56.0, 50.0, 48.0, 50.0, 54.0, 52.0, 49.0, 51.0, 51.0, 56.0]
+;