assertFalse(Strings.validSurrogatePairAt("x\uDCAB", 0));
    assertFalse(Strings.validSurrogatePairAt("\uD8ABx", 0));
  }

  @SuppressWarnings("LenientFormatStringValidation") // Intentional for testing.
  public void testLenientFormat() {
    assertEquals("%s", Strings.lenientFormat("%s"));
    assertEquals("5", Strings.lenientFormat("%s", 5));

import org.jspecify.annotations.Nullable;

/**
 * Unit test for {@link Preconditions}.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 */
@NullMarked
@SuppressWarnings("LenientFormatStringValidation") // Intentional for testing
@GwtCompatible
public class PreconditionsTest extends TestCase {
  public void testCheckArgument_simple_success() {
    checkArgument(true);
  }

import org.jspecify.annotations.Nullable;

/**
 * Unit test for {@link Preconditions}.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 */
@NullMarked
@SuppressWarnings("LenientFormatStringValidation") // Intentional for testing
@GwtCompatible
public class PreconditionsTest extends TestCase {
  public void testCheckArgument_simple_success() {
    checkArgument(true);
  }