it.ozimov.cirneco.hamcrest.number.IsNegative Maven / Gradle / Ivy

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package it.ozimov.cirneco.hamcrest.number;

import org.hamcrest.Description;
import org.hamcrest.Matcher;
import org.hamcrest.TypeSafeMatcher;


/**
 * Is the value a {@linkplain Number} with negative  value?
 *
 * @since version 0.2 for JDK7
 */
public class IsNegative extends TypeSafeMatcher {

    /**
     * Creates a matcher for {@code N} that matches when the it has a value that is less than zero.
     * 
     * For example:
     * 
assertThat(-100, negative())
     * will return true.
     */
    public static  Matcher negative() {
        return new IsNegative<>();
    }

    @Override
    protected boolean matchesSafely(final N number) {
        return number.doubleValue() < 0D;
    }

    @Override
    protected void describeMismatchSafely(final N item, final Description mismatchDescription) {
        mismatchDescription.appendValue(item)
                .appendText(" is not negative");
    }

    @Override
    public void describeTo(final Description description) {
        description.appendText("a negative value");
    }

}