1 files changed, 203 insertions, 0 deletions
diff --git a/javatests/com/google/gerrit/server/cache/mem/DefaultMemoryCacheFactoryTest.java b/javatests/com/google/gerrit/server/cache/mem/DefaultMemoryCacheFactoryTest.java
new file mode 100644
index 0000000000..595846571f
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/mem/DefaultMemoryCacheFactoryTest.java
@@ -0,0 +1,203 @@
+// Copyright (C) 2022 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cache.mem;
+
+import static com.google.common.base.Functions.identity;
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.cache.Weigher;
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.server.cache.CacheDef;
+import com.google.inject.TypeLiteral;
+import java.time.Duration;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.BrokenBarrierException;
+import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+import org.eclipse.jgit.lib.Config;
+import org.junit.Before;
+import org.junit.Test;
+
+public class DefaultMemoryCacheFactoryTest {
+
+  private static final String TEST_CACHE = "test-cache";
+  private static final long TEST_TIMEOUT_SEC = 1;
+  private static final int TEST_CACHE_KEY = 1;
+
+  private DefaultMemoryCacheFactory memoryCacheFactory;
+  private Config memoryCacheConfig;
+  private ScheduledExecutorService executor;
+  private CyclicBarrier cacheGetStarted;
+  private CyclicBarrier cacheGetCompleted;
+
+  @Before
+  public void setUp() {
+    memoryCacheConfig = new Config();
+    memoryCacheFactory = new DefaultMemoryCacheFactory(memoryCacheConfig, null);
+    executor = Executors.newScheduledThreadPool(1);
+    cacheGetStarted = new CyclicBarrier(2);
+    cacheGetCompleted = new CyclicBarrier(2);
+  }
+
+  @Test
+  public void shouldNotBlockEvictionsWhenCacheIsDisabledByDefault() throws Exception {
+    LoadingCache<Integer, Integer> disabledCache =
+        memoryCacheFactory.build(newCacheDef(0), newCacheLoader(identity()));
+
+    assertCacheEvictionIsNotBlocking(disabledCache);
+  }
+
+  @Test
+  public void shouldNotBlockEvictionsWhenCacheIsDisabledByConfiguration() throws Exception {
+    memoryCacheConfig.setInt("cache", TEST_CACHE, "memoryLimit", 0);
+    LoadingCache<Integer, Integer> disabledCache =
+        memoryCacheFactory.build(newCacheDef(1), newCacheLoader(identity()));
+
+    assertCacheEvictionIsNotBlocking(disabledCache);
+  }
+
+  @Test
+  public void shouldBlockEvictionsWhenCacheIsEnabled() throws Exception {
+    LoadingCache<Integer, Integer> cache =
+        memoryCacheFactory.build(newCacheDef(1), newCacheLoader(identity()));
+
+    ScheduledFuture<Integer> cacheValue =
+        executor.schedule(() -> cache.getUnchecked(TEST_CACHE_KEY), 0, TimeUnit.SECONDS);
+
+    cacheGetStarted.await(TEST_TIMEOUT_SEC, TimeUnit.SECONDS);
+    cache.invalidate(TEST_CACHE_KEY);
+
+    assertThat(cacheValue.isDone()).isTrue();
+    assertThat(cacheValue.get()).isEqualTo(TEST_CACHE_KEY);
+  }
+
+  @Test
+  public void shouldLoadAllKeysWithDisabledCache() throws Exception {
+    LoadingCache<Integer, Integer> disabledCache =
+        memoryCacheFactory.build(newCacheDef(0), newCacheLoader(identity()));
+
+    List<Integer> keys = Arrays.asList(1, 2);
+    ImmutableMap<Integer, Integer> entries = disabledCache.getAll(keys);
+
+    assertThat(entries).containsExactly(1, 1, 2, 2);
+  }
+
+  private void assertCacheEvictionIsNotBlocking(LoadingCache<Integer, Integer> disabledCache)
+      throws InterruptedException, BrokenBarrierException, TimeoutException, ExecutionException {
+    ScheduledFuture<Integer> cacheValue =
+        executor.schedule(() -> disabledCache.getUnchecked(TEST_CACHE_KEY), 0, TimeUnit.SECONDS);
+    cacheGetStarted.await(TEST_TIMEOUT_SEC, TimeUnit.SECONDS);
+    disabledCache.invalidate(TEST_CACHE_KEY);
+
+    // The invalidate did not wait for the cache loader to finish, therefore the cacheValue isn't
+    // done yet
+    assertThat(cacheValue.isDone()).isFalse();
+
+    // The cache loader completes after the invalidation
+    cacheGetCompleted.await(TEST_TIMEOUT_SEC, TimeUnit.SECONDS);
+    assertThat(cacheValue.get()).isEqualTo(TEST_CACHE_KEY);
+  }
+
+  private CacheLoader<Integer, Integer> newCacheLoader(Function<Integer, Integer> loadFunc) {
+    return new CacheLoader<>() {
+
+      @Override
+      public Integer load(Integer n) throws Exception {
+        Integer v = 0;
+        try {
+          cacheGetStarted.await(TEST_TIMEOUT_SEC, TimeUnit.SECONDS);
+          v = loadFunc.apply(n);
+          cacheGetCompleted.await(TEST_TIMEOUT_SEC, TimeUnit.SECONDS);
+        } catch (TimeoutException | BrokenBarrierException e) {
+          // Just continue
+        }
+        return v;
+      }
+
+      @Override
+      public Map<Integer, Integer> loadAll(Iterable<? extends Integer> keys) throws Exception {
+        return StreamSupport.stream(keys.spliterator(), false)
+            .collect(Collectors.toMap(identity(), identity()));
+      }
+    };
+  }
+
+  private CacheDef<Integer, Integer> newCacheDef(long maximumWeight) {
+    return new CacheDef<>() {
+
+      @Override
+      public String name() {
+        return TEST_CACHE;
+      }
+
+      @Override
+      public String configKey() {
+        return TEST_CACHE;
+      }
+
+      @Override
+      public TypeLiteral<Integer> keyType() {
+        return null;
+      }
+
+      @Override
+      public TypeLiteral<Integer> valueType() {
+        return null;
+      }
+
+      @Override
+      public long maximumWeight() {
+        return maximumWeight;
+      }
+
+      @Override
+      public Duration expireAfterWrite() {
+        return null;
+      }
+
+      @Override
+      public Duration expireFromMemoryAfterAccess() {
+        return null;
+      }
+
+      @Override
+      public Duration refreshAfterWrite() {
+        return null;
+      }
+
+      @Override
+      public Weigher<Integer, Integer> weigher() {
+        return null;
+      }
+
+      @Override
+      public CacheLoader<Integer, Integer> loader() {
+        return null;
+      }
+    };
+  }
+}