DATAREDIS-481 - Apply existing tests to new implementation

Author: christophstrobl

src/main/java/org/springframework/data/redis/cache/NRedisCache.java

@@ -100,7 +100,7 @@ public RedisCacheWriter getNativeCache() {
 	}
 
 	@Override
-	public <T> T get(Object key, Callable<T> valueLoader) {
+	public synchronized <T> T get(Object key, Callable<T> valueLoader) {
 
 		ValueWrapper result = get(key);
 
@@ -119,7 +119,10 @@ public void put(Object key, Object value) {
 		Object cacheValue = preProcessCacheValue(value);
 
 		if (!isAllowNullValues() && cacheValue == null) {
-			return;
+
+			throw new IllegalArgumentException(String.format(
+					"Cache '%s' does not allow 'null' values. Avoid storing null via '@Cacheable(unless=\"#result == null\")' or configure RedisCache to allow 'null' via RedisCacheConfiguration.",
+					name));
 		}
 
 		cacheWriter.put(name, createAndConvertCacheKey(key), serializeCacheValue(cacheValue), cacheConfig.getTimeout());

src/test/java/org/springframework/data/redis/cache/AbstractNativeCacheTest.java

@@ -19,10 +19,12 @@
 import static org.junit.Assert.*;
 import static org.springframework.data.redis.matcher.RedisTestMatchers.*;
 
+import org.hamcrest.core.IsInstanceOf;
 import org.junit.Before;
 import org.junit.Test;
 import org.springframework.cache.Cache;
 import org.springframework.cache.Cache.ValueWrapper;
+import org.springframework.data.redis.core.RedisTemplate;
 
 /**
  * Test for native cache implementations.
@@ -66,7 +68,7 @@ public void testCacheName() throws Exception {
 
 	@Test
 	public void testNativeCache() throws Exception {
-		assertSame(nativeCache, cache.getNativeCache());
+		assertThat(cache.getNativeCache(), IsInstanceOf.instanceOf(RedisTemplate.class));
 	}
 
 	@Test