poi/poi/src/test/java/org/apache/poi/util/TestLocaleUtil.java

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   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
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       http://www.apache.org/licenses/LICENSE-2.0

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   distributed under the License is distributed on an "AS IS" BASIS,
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package org.apache.poi.util;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotEquals;
import static org.junit.jupiter.api.Assumptions.assumeFalse;

import java.util.Calendar;
import java.util.Locale;
import java.util.TimeZone;

import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;


class TestLocaleUtil {
    // This unit test assumes that the user's locale isn't ja-JP and timezone isn't Asia/Tokyo
    // If this is the case, change the values to something else
    private static final Locale ja_JP = Locale.JAPAN;
    private static final TimeZone TOKYO = TimeZone.getTimeZone("Asia/Tokyo");
    private static final Calendar JAPAN_CALENDAR = Calendar.getInstance(TOKYO, ja_JP);

    /**
     * Reset the Locale to the user default before the test so that it isn't influenced
     * by the LocaleUtil's state being changed by previous tests.
     */
    @BeforeEach
    @SuppressForbidden("implementation around default locales in POI")
    void setUp() {
        // reset the user locale and time zone so that tests do not interfere with each other
        // the other and better way would be to run each test in its own thread since
        // LocaleUtil uses per-thread settings.
        // Helpful, but not ASL 2.0 licensed:
        // http://www.codeaffine.com/2014/07/21/a-junit-rule-to-run-a-test-in-its-own-thread/
        LocaleUtil.setUserLocale(Locale.getDefault());
        LocaleUtil.setUserTimeZone(TimeZone.getDefault());

        assumeFalse(ja_JP.equals(LocaleUtil.getUserLocale()));
        assumeFalse(TOKYO.equals(LocaleUtil.getUserTimeZone()));
    }

    /**
     * Reset the Locale to the user default after the test so that it doesn't influence
     * other tests.
     */
    @AfterEach
    void tearDown() {
        LocaleUtil.resetUserLocale();
        LocaleUtil.resetUserTimeZone();
    }

    @Test
    @SuppressForbidden("implementation around default locales in POI")
    void userLocale() {
        Locale DEFAULT_LOCALE = LocaleUtil.getUserLocale();

        assertEquals(DEFAULT_LOCALE, LocaleUtil.getUserLocale());
        assertNotEquals(ja_JP, LocaleUtil.getUserLocale());

        LocaleUtil.setUserLocale(ja_JP);
        assertEquals(ja_JP, LocaleUtil.getUserLocale());

        LocaleUtil.resetUserLocale();
        assertEquals(DEFAULT_LOCALE, LocaleUtil.getUserLocale());
    }

    @Test
    @SuppressForbidden("implementation around default locales in POI")
    void userTimeZone() {
        TimeZone DEFAULT_TIME_ZONE = LocaleUtil.getUserTimeZone();

        assertEquals(DEFAULT_TIME_ZONE, LocaleUtil.getUserTimeZone());
        assertNotEquals(TOKYO, LocaleUtil.getUserTimeZone());

        LocaleUtil.setUserTimeZone(TOKYO);
        assertEquals(TOKYO, LocaleUtil.getUserTimeZone());
    }

    @Test
    @SuppressForbidden("implementation around default locales in POI")
    void localeCalendar() {
        Locale DEFAULT_LOCALE = LocaleUtil.getUserLocale();
        TimeZone DEFAULT_TIME_ZONE = LocaleUtil.getUserTimeZone();
        Calendar DEFAULT_CALENDAR = LocaleUtil.getLocaleCalendar();

        assertEquals(DEFAULT_LOCALE, LocaleUtil.getUserLocale());
        assertEquals(DEFAULT_TIME_ZONE, LocaleUtil.getUserTimeZone());
        assertCalendarEquals(DEFAULT_CALENDAR, LocaleUtil.getLocaleCalendar());
        assertNotEquals(ja_JP, LocaleUtil.getUserLocale());
        assertNotEquals(TOKYO, LocaleUtil.getUserTimeZone());
        assertCalendarNotEquals(JAPAN_CALENDAR, LocaleUtil.getLocaleCalendar());

        LocaleUtil.setUserLocale(ja_JP);
        LocaleUtil.setUserTimeZone(TOKYO);
        assertCalendarEquals(JAPAN_CALENDAR, LocaleUtil.getLocaleCalendar());
        assertCalendarEquals(JAPAN_CALENDAR, LocaleUtil.getLocaleCalendar(TOKYO));
        // FIXME: These might affect the time zone due to daylight savings:
        //assertCalendarEquals(JAPAN_CALENDAR, LocaleUtil.getLocaleCalendar(2016, 00, 01));
        //assertCalendarEquals(JAPAN_CALENDAR, LocaleUtil.getLocaleCalendar(2016, 00, 01, 00, 00, 00));
    }

    private static void assertCalendarNotEquals(Calendar expected, Calendar actual) {
        // FIXME: add more tests to compare calendars, ignoring whether the dates are equal
        assertNotEquals(expected.getTimeZone(), actual.getTimeZone(), "time zone");
    }
    private static void assertCalendarEquals(Calendar expected, Calendar actual) {
        // FIXME: add more tests to compare calendars, ignoring whether the set dates are equal
        assertEquals(expected.getTimeZone(), actual.getTimeZone(), "time zone");
    }
}