Fix NoOpCache handling of get(key,callable)

This commit fixes the method that takes a Callable to actually always
invoke it rather than returning null.

Issue: SPR-14445

spring-context/src/main/java/org/springframework/cache/support/NoOpCacheManager.java

@@ -102,7 +102,12 @@ public class NoOpCacheManager implements CacheManager {
 
 		@Override
 		public <T> T get(Object key, Callable<T> valueLoader) {
-			return null;
+			try {
+				return valueLoader.call();
+			}
+			catch (Exception ex) {
+				throw new ValueRetrievalException(key, valueLoader, ex);
+			}
 		}
 
 		@Override

spring-context/src/test/java/org/springframework/cache/NoOpCacheManagerTests.java

@@ -18,33 +18,33 @@ package org.springframework.cache;
 
 import java.util.UUID;
 
-import org.junit.Before;
 import org.junit.Test;
 
 import org.springframework.cache.support.NoOpCacheManager;
 
 import static org.junit.Assert.*;
 
+/**
+ * Tests for {@link NoOpCacheManager}.
+ *
+ * @author Costin Leau
+ * @author Stephane Nicoll
+ */
 public class NoOpCacheManagerTests {
 
-	private CacheManager manager;
-
-	@Before
-	public void setup() {
-		manager = new NoOpCacheManager();
-	}
+	private final CacheManager manager = new NoOpCacheManager();
 
 	@Test
 	public void testGetCache() throws Exception {
-		Cache cache = manager.getCache("bucket");
+		Cache cache = this.manager.getCache("bucket");
 		assertNotNull(cache);
-		assertSame(cache, manager.getCache("bucket"));
+		assertSame(cache, this.manager.getCache("bucket"));
 	}
 
 	@Test
 	public void testNoOpCache() throws Exception {
-		String name = UUID.randomUUID().toString();
-		Cache cache = manager.getCache(name);
+		String name = createRandomKey();
+		Cache cache = this.manager.getCache(name);
 		assertEquals(name, cache.getName());
 		Object key = new Object();
 		cache.put(key, new Object());
@@ -56,8 +56,37 @@ public class NoOpCacheManagerTests {
 	@Test
 	public void testCacheName() throws Exception {
 		String name = "bucket";
-		assertFalse(manager.getCacheNames().contains(name));
-		manager.getCache(name);
-		assertTrue(manager.getCacheNames().contains(name));
+		assertFalse(this.manager.getCacheNames().contains(name));
+		this.manager.getCache(name);
+		assertTrue(this.manager.getCacheNames().contains(name));
+	}
+
+	@Test
+	public void testCacheCallable() throws Exception {
+		String name = createRandomKey();
+		Cache cache = this.manager.getCache(name);
+		Object returnValue = new Object();
+		Object value = cache.get(new Object(), () -> returnValue);
+		assertEquals(returnValue, value);
 	}
+
+	@Test
+	public void testCacheGetCallableFail() {
+		Cache cache = this.manager.getCache(createRandomKey());
+		String key = createRandomKey();
+		try {
+			cache.get(key, () -> {
+				throw new UnsupportedOperationException("Expected exception");
+			});
+		}
+		catch (Cache.ValueRetrievalException ex) {
+			assertNotNull(ex.getCause());
+			assertEquals(UnsupportedOperationException.class, ex.getCause().getClass());
+		}
+	}
+
+	private String createRandomKey() {
+		return UUID.randomUUID().toString();
+	}
+
 }