Keep the same pass check behavior for FactCheckingEvaluator and RelevancyEvaluator, and avoid NPE. (spring-projects#3975)

Fixes spring-projects#3975

Auto-cherry-pick to 1.0.x

Signed-off-by: Mengqi Xu <[email protected]>

Author: remeio

spring-ai-client-chat/src/main/java/org/springframework/ai/chat/evaluation/FactCheckingEvaluator.java

@@ -134,7 +134,7 @@ public EvaluationResponse evaluate(EvaluationRequest evaluationRequest) {
 			.call()
 			.content();
 
-		boolean passing = evaluationResponse.equalsIgnoreCase("yes");
+		boolean passing = "yes".equalsIgnoreCase(evaluationResponse);
 		return new EvaluationResponse(passing, "", Collections.emptyMap());
 	}
 

spring-ai-client-chat/src/main/java/org/springframework/ai/chat/evaluation/RelevancyEvaluator.java

@@ -79,7 +79,7 @@ public EvaluationResponse evaluate(EvaluationRequest evaluationRequest) {
 
 		boolean passing = false;
 		float score = 0;
-		if (evaluationResponse != null && evaluationResponse.toLowerCase().contains("yes")) {
+		if ("yes".equalsIgnoreCase(evaluationResponse)) {
 			passing = true;
 			score = 1;
 		}