Integer arithmetic slower than floating point arithmetic

/**
 *
 */
package media

import org.junit.BeforeClass
import org.junit.Test
import org.apache.commons.lang.time.StopWatch
import static org.junit.Assert.*

/**
 * Compares the performance of integer and floating point arithmetic in Groovy.
 *
 * @author <a href="http://johannburkard.de">Johann Burkard</a>
 * @see <a href="http://groovy-programming.com">Groovy Programming</a>
 */
class LongDivisionTest {

    static final long start = 1

    static final long tests = 100000

    @BeforeClass
    static void setUpBeforeClass() {
        println 'Warming up, this could take 5 s or so'
        (start..tests).each {
            tests / it
            (double) tests / it
        }
    }

    @Test
    void longDivision() {
        StopWatch watch = new StopWatch()
        watch.start()
        (start..tests).each {
            tests / it
        }
        println "long: ${watch.time}"
    }

    @Test
    void doubleDivision() {
        StopWatch watch = new StopWatch()
        watch.start()
        (start..tests).each {
            (double) tests / it
        }
        println "double: ${watch.time}"
    }

    @Test
    void deepLongDivision() {
        deepLongDivision1()
    }

    void deepLongDivision1() {
        deepLongDivision2()
    }

    void deepLongDivision2() {
        deepLongDivision3()
    }

    void deepLongDivision3() {
        StopWatch watch = new StopWatch()
        watch.start()
        (start..tests).each {
            tests / it
        }
        println "long (deep): ${watch.time}"
    }

}