test/jdk/java/util/Locale/TestOf.java

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/**
 * @test
 * @bug 8282819
 * @summary Unit tests for Locale.of() method. Those tests check the equality
 *      of obtained objects with ones that are gotten from other means with both
 *      well-formed and ill-formed arguments. Also checks the possible NPEs
 *      for error cases.
 * @run testng TestOf
 */
import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertThrows;

import java.util.Locale;

import org.testng.annotations.Test;
import org.testng.annotations.DataProvider;

@SuppressWarnings("deprecation")
@Test
public class TestOf {

    @DataProvider
    public Object[][] data_1Arg() {
        return new Object[][]{
                // well-formed
                {Locale.ENGLISH, "en"},
                {Locale.JAPANESE, "ja"},

                // ill-formed
                {Locale.ROOT, ""},
                {new Locale("a"), "a"},
                {new Locale("xxxxxxxxxx"), "xxxxxxxxxx"},
        };
    }

    @DataProvider
    public Object[][] data_2Args() {
        return new Object[][]{
                // well-formed
                {Locale.US, "en", "US"},
                {Locale.JAPAN, "ja", "JP"},

                // ill-formed
                {new Locale("", "US"), "", "US"},
                {new Locale("a", "b"), "a", "b"},
                {new Locale("xxxxxxxxxx", "yyyyyyyyyy"), "xxxxxxxxxx", "yyyyyyyyyy"},
        };
    }

    @DataProvider
    public Object[][] data_3Args() {
        return new Object[][]{
                // well-formed
                {Locale.forLanguageTag("en-US-POSIX"), "en", "US", "POSIX"},
                {Locale.forLanguageTag("ja-JP-POSIX"), "ja", "JP", "POSIX"},

                // ill-formed
                {new Locale("", "", "POSIX"), "", "", "POSIX"},
                {new Locale("a", "b", "c"), "a", "b", "c"},
                {new Locale("xxxxxxxxxx", "yyyyyyyyyy", "zzzzzzzzzz"),
                        "xxxxxxxxxx", "yyyyyyyyyy", "zzzzzzzzzz"},
                {new Locale("ja", "JP", "JP"), "ja", "JP", "JP"},
                {new Locale("th", "TH", "TH"), "th", "TH", "TH"},
                {new Locale("no", "NO", "NY"), "no", "NO", "NY"},
        };
    }

    @Test (dataProvider = "data_1Arg")
    public void test_1Arg(Locale expected, String lang) {
        assertEquals(Locale.of(lang), expected);
    }

    @Test (dataProvider = "data_2Args")
    public void test_2Args(Locale expected, String lang, String ctry) {
        assertEquals(Locale.of(lang, ctry), expected);
    }

    @Test (dataProvider = "data_3Args")
    public void test_3Args(Locale expected, String lang, String ctry, String vrnt) {
        assertEquals(Locale.of(lang, ctry, vrnt), expected);
    }

    @Test
    public void test_NPE() {
        assertThrows(NullPointerException.class, () -> Locale.of(null));
        assertThrows(NullPointerException.class, () -> Locale.of("", null));
        assertThrows(NullPointerException.class, () -> Locale.of("", "", null));
    }
}