add tests

spring-boot-modules/spring-boot-libraries/src/main/java/com/baeldung/ratelimiting/bucket4japp/interceptor/RateLimitInterceptor.java

@@ -5,6 +5,7 @@ import javax.servlet.http.HttpServletResponse;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
 import org.springframework.stereotype.Component;
 import org.springframework.web.servlet.HandlerInterceptor;
 
@@ -44,10 +45,11 @@ public class RateLimitInterceptor implements HandlerInterceptor {
 
         } else {
 
-            long waitForRefill = probe.getNanosToWaitForRefill() % 1_000_000_000;
+            long waitForRefill = probe.getNanosToWaitForRefill() / 1_000_000_000;
 
-            response.sendError(HttpStatus.TOO_MANY_REQUESTS.value(), "You have exhausted your API Request Quota"); // 429
+            response.setContentType(MediaType.APPLICATION_JSON_VALUE);
             response.addHeader(HEADER_RETRY_AFTER, String.valueOf(waitForRefill));
+            response.sendError(HttpStatus.TOO_MANY_REQUESTS.value(), "You have exhausted your API Request Quota"); // 429
 
             return false;
         }

spring-boot-modules/spring-boot-libraries/src/main/java/com/baeldung/ratelimiting/bucket4japp/service/PricingPlan.java

@@ -5,34 +5,28 @@ import java.time.Duration;
 import io.github.bucket4j.Bandwidth;
 import io.github.bucket4j.Refill;
 
-enum PricingPlan {
+public enum PricingPlan {
 
-    FREE {
+    FREE(20),
 
-        @Override
-        Bandwidth getLimit() {
-            return Bandwidth.classic(20, Refill.intervally(20, Duration.ofHours(1)));
-        }
-    },
+    BASIC(40),
 
-    BASIC {
-
-        @Override
-        Bandwidth getLimit() {
-            return Bandwidth.classic(40, Refill.intervally(40, Duration.ofHours(1)));
-        }
-    },
-
-    PROFESSIONAL {
-
-        @Override
-        Bandwidth getLimit() {
-            return Bandwidth.classic(100, Refill.intervally(100, Duration.ofHours(1)));
-        }
-    };
-
-    abstract Bandwidth getLimit();
+    PROFESSIONAL(100);;
 
+    private int bucketCapacity;
+    
+    private PricingPlan(int bucketCapacity) {
+        this.bucketCapacity = bucketCapacity;
+    }
+    
+    Bandwidth getLimit() {
+        return Bandwidth.classic(bucketCapacity, Refill.intervally(bucketCapacity, Duration.ofHours(1)));
+    }
+    
+    public int bucketCapacity() {
+        return bucketCapacity;
+    }
+    
     static PricingPlan resolvePlanFromApiKey(String apiKey) {
         if (apiKey == null || apiKey.isEmpty()) {
             return FREE;