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*
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
/* @test
* @summary Basic functional test of Optional
* @author Mike Duigou
* @run testng Basic
*/
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.stream.Stream;
import static java.util.stream.Collectors.toList;
import static org.testng.Assert.*;
import org.testng.annotations.Test;
public class Basic {
/**
* Asserts that the runnable throws an exception of the given type.
* Fails if no exception is thrown, or if an exception of the wrong
* type is thrown. This is used instead of @Test(expectedExceptions)
* because that can be applied only at the granularity of a test.
*/
void assertThrows(Runnable r, Class<? extends Exception> clazz) {
try {
r.run();
fail();
} catch (Exception ex) {
assertTrue(clazz.isInstance(ex));
}
}
/**
* Checks a block of assertions over an empty Optional.
*/
void checkEmpty(Optional<String> empty) {
assertTrue(empty.equals(Optional.empty()));
assertTrue(Optional.empty().equals(empty));
assertFalse(empty.equals(Optional.of("")));
assertFalse(Optional.of("").equals(empty));
assertFalse(empty.isPresent());
assertEquals(empty.hashCode(), 0);
assertEquals(empty.orElse("x"), "x");
assertEquals(empty.orElseGet(() -> "y"), "y");
assertThrows(() -> empty.get(), NoSuchElementException.class);
assertThrows(() -> empty.orElseThrow(), NoSuchElementException.class);
assertThrows(() -> empty.orElseThrow(ObscureException::new), ObscureException.class);
var b = new AtomicBoolean();
empty.ifPresent(s -> b.set(true));
assertFalse(b.get());
var b1 = new AtomicBoolean(false);
var b2 = new AtomicBoolean(false);
empty.ifPresentOrElse(s -> b1.set(true), () -> b2.set(true));
assertFalse(b1.get());
assertTrue(b2.get());
}
/**
* Checks a block of assertions over an Optional that is expected to
* have a particular value present.
*/
void checkPresent(Optional<String> opt, String expected) {
assertFalse(opt.equals(Optional.empty()));
assertFalse(Optional.empty().equals(opt));
assertTrue(opt.equals(Optional.of(expected)));
assertTrue(Optional.of(expected).equals(opt));
assertFalse(opt.equals(Optional.of("unexpected")));
assertFalse(Optional.of("unexpected").equals(opt));
assertTrue(opt.isPresent());
assertEquals(opt.hashCode(), expected.hashCode());
assertEquals(opt.orElse("unexpected"), expected);
assertEquals(opt.orElseGet(() -> "unexpected"), expected);
assertEquals(opt.get(), expected);
assertEquals(opt.orElseThrow(), expected);
assertEquals(opt.orElseThrow(ObscureException::new), expected);
var b = new AtomicBoolean(false);
opt.ifPresent(s -> b.set(true));
assertTrue(b.get());
var b1 = new AtomicBoolean(false);
var b2 = new AtomicBoolean(false);
opt.ifPresentOrElse(s -> b1.set(true), () -> b2.set(true));
assertTrue(b1.get());
assertFalse(b2.get());
}
@Test
public void testEmpty() {
checkEmpty(Optional.empty());
}
@Test
public void testOfNull() {
assertThrows(() -> Optional.of(null), NullPointerException.class);
}
@Test
public void testOfPresent() {
checkPresent(Optional.of("xyzzy"), "xyzzy");
}
@Test
public void testOfNullableNull() {
checkEmpty(Optional.ofNullable(null));
}
@Test
public void testOfNullablePresent() {
checkPresent(Optional.of("xyzzy"), "xyzzy");
}
@Test
public void testFilterEmpty() {
checkEmpty(Optional.<String>empty().filter(s -> { fail(); return true; }));
}
@Test
public void testFilterFalse() {
checkEmpty(Optional.of("xyzzy").filter(s -> s.equals("plugh")));
}
@Test
public void testFilterTrue() {
checkPresent(Optional.of("xyzzy").filter(s -> s.equals("xyzzy")), "xyzzy");
}
@Test
public void testMapEmpty() {
checkEmpty(Optional.empty().map(s -> { fail(); return ""; }));
}
@Test
public void testMapPresent() {
checkPresent(Optional.of("xyzzy").map(s -> s.replace("xyzzy", "plugh")), "plugh");
}
@Test
public void testFlatMapEmpty() {
checkEmpty(Optional.empty().flatMap(s -> { fail(); return Optional.of(""); }));
}
@Test
public void testFlatMapPresentReturnEmpty() {
checkEmpty(Optional.of("xyzzy")
.flatMap(s -> { assertEquals(s, "xyzzy"); return Optional.empty(); }));
}
@Test
public void testFlatMapPresentReturnPresent() {
checkPresent(Optional.of("xyzzy")
.flatMap(s -> { assertEquals(s, "xyzzy"); return Optional.of("plugh"); }),
"plugh");
}
/*
@Test
public void testOrEmptyEmpty() {
checkEmpty(Optional.<String>empty().or(() -> Optional.empty()));
}
@Test
public void testOrEmptyPresent() {
checkPresent(Optional.<String>empty().or(() -> Optional.of("plugh")), "plugh");
}
@Test
public void testOrPresentDontCare() {
checkPresent(Optional.of("xyzzy").or(() -> { fail(); return Optional.of("plugh"); }), "xyzzy");
}
*/
@Test
public void testStreamEmpty() {
assertEquals(Optional.empty().stream().collect(toList()), List.of());
}
@Test
public void testStreamPresent() {
assertEquals(Optional.of("xyzzy").stream().collect(toList()), List.of("xyzzy"));
}
private static class ObscureException extends RuntimeException { }
}