Class TestCache

distributed-cache/src/test/java/TestCache.java:20–366

import java.util.stream.Collectors;

public class TestCache {

    private static final String PROFILE_MUMBAI_ENGINEER = "profile_mumbai_engineer", PROFILE_HYDERABAD_ENGINEER = "profile_hyderabad_engineer";
    private final Map<String, String> dataMap = new ConcurrentHashMap<>();
    private final Queue<CompletableFuture<Void>> writeOperations = new LinkedList<>();
    private DataSource<String, String> dataSource;
    private DataSource<String, String> writeBackDataSource;

    @Before
    public void setUp() {
        dataMap.clear();
        writeOperations.clear();
        dataMap.put(PROFILE_MUMBAI_ENGINEER, "violet");
        dataMap.put(PROFILE_HYDERABAD_ENGINEER, "blue");
        dataSource = new DataSource<>() {
            @Override
            public CompletionStage<String> load(String key) {
                if (dataMap.containsKey(key)) {
                    return CompletableFuture.completedFuture(dataMap.get(key));
                } else {
                    return CompletableFuture.failedStage(new NullPointerException());
                }
            }

            @Override
            public CompletionStage<Void> persist(String key, String value, long timestamp) {
                dataMap.put(key, value);
                return CompletableFuture.completedFuture(null);
            }
        };

        writeBackDataSource = new DataSource<>() {
            @Override
            public CompletionStage<String> load(String key) {
                if (dataMap.containsKey(key)) {
                    return CompletableFuture.completedFuture(dataMap.get(key));
                } else {
                    return CompletableFuture.failedStage(new NullPointerException());
                }
            }

            @Override
            public CompletionStage<Void> persist(String key, String value, long timestamp) {
                final CompletableFuture<Void> hold = new CompletableFuture<>();
                writeOperations.add(hold);
                return hold.thenAccept(__ -> dataMap.put(key, value));
            }
        };
    }

    private void acceptWrite() {
        final CompletableFuture<Void> write = writeOperations.poll();
        if (write != null) {
            write.complete(null);
        }
    }

    @Test(expected = IllegalArgumentException.class)