test(TestInferenceService): prevent negative embedding values (elastic#136806)

Author: mromaios

x-pack/plugin/inference/qa/test-service-plugin/src/main/java/org/elasticsearch/xpack/inference/mock/TestSparseInferenceServiceExtension.java

@@ -215,7 +215,9 @@ protected ServiceSettings getServiceSettingsFromMap(Map<String, Object> serviceS
 
         private static float generateEmbedding(String input, int position) {
             // Ensure non-negative and non-zero values for features
-            return Math.abs(input.hashCode()) + 1 + position;
+            int hash = input.hashCode();
+            int absHash = (hash == Integer.MIN_VALUE) ? Integer.MAX_VALUE : Math.abs(hash);
+            return absHash + 1.0f + position;
         }
 
         public static class Configuration {