UniqueValueGeneratorTest.java

package gov.samhsa.consent2share.common;

import static org.junit.Assert.assertEquals;
import gov.samhsa.consent2share.common.UniqueValueGenerator;
import gov.samhsa.consent2share.common.UniqueValueGeneratorException;

import java.util.concurrent.atomic.AtomicInteger;

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

public class UniqueValueGeneratorTest {
	private static final String TEST_VALUE = "TEST_VALUE";
	private static final short LIMIT = 3;

	@Rule
	public ExpectedException thrown = ExpectedException.none();

	@Test
	public void testGenerateUniqueValue_Success_First_Trial() {
		// Arrange
		AtomicInteger counter = new AtomicInteger(0);

		// Act
		String value = UniqueValueGenerator.generateUniqueValue(
				() -> TEST_VALUE, v -> {
					counter.incrementAndGet();
					return true;
				}, LIMIT);

		// Assert
		assertEquals(TEST_VALUE, value);
		assertEquals(1, counter.get());
	}

	@Test
	public void testGenerateUniqueValue_Success_Last_Trial() {
		// Arrange
		AtomicInteger counter = new AtomicInteger(0);

		// Act
		String value = UniqueValueGenerator.generateUniqueValue(
				() -> TEST_VALUE, v -> counter.incrementAndGet() >= LIMIT,
				LIMIT);

		// Assert
		assertEquals(TEST_VALUE, value);
		assertEquals(LIMIT, counter.get());
	}

	@Test
	public void testGenerateUniqueValue_Throws_UniqueValueGeneratorException_Last_Trial1() {
		// Arrange
		AtomicInteger counter = new AtomicInteger(0);
		thrown.expect(UniqueValueGeneratorException.class);

		// Act
		String value = null;
		try {
			value = UniqueValueGenerator.generateUniqueValue(() -> TEST_VALUE,
					v -> {
						counter.incrementAndGet();
						return false;
					}, LIMIT);
		} catch (Exception e) {
			// Assert
			assertEquals(null, value);
			assertEquals(LIMIT, counter.get());
			throw e;
		}
	}

	@Test
	public void testGenerateUniqueValue_Throws_UniqueValueGeneratorException_Last_Trial2() {
		// Arrange
		AtomicInteger counter = new AtomicInteger(0);
		thrown.expect(UniqueValueGeneratorException.class);

		// Act
		String value = null;
		try {
			value = UniqueValueGenerator.generateUniqueValue(() -> TEST_VALUE,
					v -> counter.incrementAndGet() > LIMIT, LIMIT);
		} catch (Exception e) {
			// Assert
			assertEquals(null, value);
			assertEquals(LIMIT, counter.get());
			throw e;
		}
	}
}