test/java/lang/String/CaseConvertSameInstance.java

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/* @test
   @bug 4130097
   @summary toUpperCase and toLowerCase always return a new String,
            whereas if there is no conversion that needs to be done,
            they should be returning the same instance.
   @author James Bond/007
*/
public class CaseConvertSameInstance {
    public static void main(String[] args) throws Exception {
        /* these two are the real tests for this bug. */
        if ("foobar".toLowerCase() != "foobar")
            throw new Exception("toLowerCase returned different object");
        if ("FOOBAR".toUpperCase() != "FOOBAR")
            throw new Exception("toUpperCase returned different object");

        /* sanity test toLowerCase with some border conditions. */
        if (!("FooBar".toLowerCase().equals("foobar")))
            throw new Exception("toLowerCase broken");
        if (!("fooBar".toLowerCase().equals("foobar")))
            throw new Exception("toLowerCase broken");
        if (!("foobaR".toLowerCase().equals("foobar")))
            throw new Exception("toLowerCase broken");
        if (!("FOOBAR".toLowerCase().equals("foobar")))
            throw new Exception("toLowerCase broken");

        /* sanity test toUpperCase with some border conditions. */
        if (!("FooBar".toUpperCase().equals("FOOBAR")))
            throw new Exception("toUpperCase broken");
        if (!("fooBar".toUpperCase().equals("FOOBAR")))
            throw new Exception("toUpperCase broken");
        if (!("foobaR".toUpperCase().equals("FOOBAR")))
            throw new Exception("toUpperCase broken");
        if (!("foobar".toUpperCase().equals("FOOBAR")))
            throw new Exception("toUpperCase broken");
    }
}