CompletionTimeServiceAssistantTest.java

package com.ldbc.driver.runtime.coordination;

import com.ldbc.driver.runtime.ConcurrentErrorReporter;
import com.ldbc.driver.temporal.SystemTimeSource;
import com.ldbc.driver.temporal.TimeSource;
import org.junit.Test;

import java.util.HashSet;

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;

public class CompletionTimeServiceAssistantTest {
    @Test
    public void shouldWaitUntilGctAdvancesAndReturnCorrectSuccessValue() throws CompletionTimeException {
        TimeSource timeSource = new SystemTimeSource();
        ConcurrentErrorReporter errorReporter = new ConcurrentErrorReporter();
        CompletionTimeServiceAssistant assistant = new CompletionTimeServiceAssistant();
        CompletionTimeService completionTimeService =
                assistant.newSynchronizedConcurrentCompletionTimeServiceFromPeerIds(new HashSet<String>());
        try {
            // initial gct should be null
            assertThat(completionTimeService.globalCompletionTimeAsMilli(), is(-1l));

            // there are no writers, gct will never advance
            boolean gctAdvancedSuccessfully =
                    assistant.waitForGlobalCompletionTime(timeSource, 0, 1000, completionTimeService, errorReporter);
            assertThat(gctAdvancedSuccessfully, is(false));
            assertThat(completionTimeService.globalCompletionTimeAsMilli(), is(-1l));

            LocalCompletionTimeWriter writer1 = completionTimeService.newLocalCompletionTimeWriter();
            LocalCompletionTimeWriter writer2 = completionTimeService.newLocalCompletionTimeWriter();

            // no initiated/completed times have been submitted, gct will never advance
            gctAdvancedSuccessfully =
                    assistant.waitForGlobalCompletionTime(timeSource, 0, 1000, completionTimeService, errorReporter);
            assertThat(gctAdvancedSuccessfully, is(false));
            assertThat(completionTimeService.globalCompletionTimeAsMilli(), is(-1l));

            assistant.writeInitiatedAndCompletedTimesToAllWriters(completionTimeService, 0);

            // gct can not be known at this stage, because more 0 times/values may arrive later
            // IT[ ] CT[0] --> GCT = ?
            gctAdvancedSuccessfully =
                    assistant.waitForGlobalCompletionTime(timeSource, 0, 1000, completionTimeService, errorReporter);
            assertThat(gctAdvancedSuccessfully, is(false));
            assertThat(completionTimeService.globalCompletionTimeAsMilli(), is(-1l));

            assistant.writeInitiatedAndCompletedTimesToAllWriters(completionTimeService, 1);

            // gct should now be 0, because no more 0 values/times can come after 1 values/times have been written to all writers
            // IT[ , ] CT[0,1] --> GCT = 0
            gctAdvancedSuccessfully =
                    assistant.waitForGlobalCompletionTime(timeSource, 0, 1000, completionTimeService, errorReporter);

            assertThat(gctAdvancedSuccessfully, is(true));
            assertThat(completionTimeService.globalCompletionTimeAsMilli(), is(0l));
        } finally {
            completionTimeService.shutdown();
        }
    }
}