}

  @MapFeature.Require({SUPPORTS_PUT, SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testCompute_presentNullToNull() {
    // The spec is somewhat ambiguous about this case, but the actual default implementation
    // in Map will remove a present null.
    initMapWithNullValue();
    assertNull(
        "Map.compute(presentMappedToNull, functionReturningNull) should return null",

message ConfigMapNodeConfigSource {
  // Namespace is the metadata.namespace of the referenced ConfigMap.
  // This field is required in all cases.
  optional string namespace = 1;

  // Name is the metadata.name of the referenced ConfigMap.
  // This field is required in all cases.
  optional string name = 2;

  // UID is the metadata.UID of the referenced ConfigMap.

	defer cancel()

	c := make(chan ioret[V], 1)
	go func() {
		v, err := work(ctx)
		c <- ioret[V]{val: v, err: err}
	}()

	select {
	case v := <-c:
		return v.val, v.err
	case <-ctx.Done():
		var zero V
		return zero, ctx.Err()
	}
}

// DeadlineWorker implements the deadline/timeout resiliency pattern.
type DeadlineWorker struct {
	timeout time.Duration

    }

    public void installArtifact(final Artifact artifact) {
        switch (artifact.getType()) {
        case THEME:
            install(artifact);
            ComponentUtil.getThemeHelper().install(artifact);
            break;
        default:
            install(artifact);
            break;
        }
    }

You can also read more about them in the <a href="https://en.wikipedia.org/wiki/Environment_variable" class="external-link" target="_blank">Wikipedia for Environment Variable</a>.

In many cases it's not very obvious how environment variables would be useful and applicable right away. But they keep showing up in many different scenarios when you are developing, so it's good to know about them.

    start();
  }

  // Thread.stop() is okay because all threads started by a test are dying at the end of the test,
  // so there is no object state put at risk by stopping the threads abruptly. In some cases a test
  // may put a thread into an uninterruptible operation intentionally, so there is no other way to
  // clean up these threads.
  @SuppressWarnings("deprecation")
  @Override
  public void tearDown() throws Exception {

	expected := false
	if locked != expected {
		t.Errorf("TestDualWriteLockTimedOut(): \nexpected %#v\ngot      %#v", expected, locked)
	}
}

// Test cases below are copied 1 to 1 from sync/rwmutex_test.go (adapted to use DRWMutex)

// Borrowed from rwmutex_test.go
func parallelReader(ctx context.Context, m *DRWMutex, clocked, cunlock, cdone chan bool) {

import com.google.common.testing.EqualsTester;
import com.google.common.testing.NullPointerTester;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Test cases for {@link Table} read operations.
 *
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public abstract class AbstractTableReadTest<C extends @Nullable Character> extends TestCase {

  // This field cannot be empty for new Events and it can have at most 128 characters.
  optional string reason = 7;

  // regarding contains the object this Event is about. In most cases it's an Object reporting controller
  // implements, e.g. ReplicaSetController implements ReplicaSets and this event is emitted because
  // it acts on some changes in a ReplicaSet object.
  // +optional

        }
    }

    /**
     * Automatically accept changes that are valid property upgrades of a getter or setter.
     *
     * Here we automatically accept the following cases:
     * - A setter `setX` of an upgraded property is removed
     * - A boolean `isX` of an upgraded property is removed
     * - A new getter `getX` is added, where the old getter is a boolean getter `isX` of an upgraded property