Function<String, @Nullable Integer> function = Functions.forMap(map, null);

    assertEquals((Integer) 1, function.apply("One"));
    assertNull(function.apply("Two"));

    // check basic sanity of equals and hashCode
    new EqualsTester()
        .addEqualityGroup(function)
        .addEqualityGroup(Functions.forMap(map, 1))
        .testEquals();
  }

  @J2ktIncompatible

    Function<String, @Nullable Integer> function = Functions.forMap(map, null);

    assertEquals((Integer) 1, function.apply("One"));
    assertNull(function.apply("Two"));

    // check basic sanity of equals and hashCode
    new EqualsTester()
        .addEqualityGroup(function)
        .addEqualityGroup(Functions.forMap(map, 1))
        .testEquals();
  }

  @J2ktIncompatible

    if (element instanceof Entry) {
      Entry<?, ?> entry = (Entry<?, ?>) element;
      element = mapEntry(entry.getKey(), entry.getValue());
    }
    assertTrue(collection.contains(element)); // sanity check
    iterator.remove();
    assertFalse(collection.contains(element));
    assertEquals(originalSize - 1, collection.size());
  }

  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})

import java.util.Set;
import junit.framework.Assert;
import junit.framework.AssertionFailedError;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Tester that runs automated sanity tests for any given class. A typical use case is to test static
 * factory classes like:
 *
 * <pre>
 * interface Book {...}
 * public class Books {
 *   public static Book hardcover(String title) {...}

import java.util.Set;
import junit.framework.Assert;
import junit.framework.AssertionFailedError;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Tester that runs automated sanity tests for any given class. A typical use case is to test static
 * factory classes like:
 *
 * <pre>
 * interface Book {...}
 * public class Books {
 *   public static Book hardcover(String title) {...}

    future.set(1);
    assertEquals(1, future.get(-1, SECONDS).intValue());
  }

  @J2ktIncompatible
  @GwtIncompatible // threads
  public void testOverflowTimeout() throws Exception {
    // First, sanity check that naive multiplication would really overflow to a negative number:
    long nanosPerSecond = NANOSECONDS.convert(1, SECONDS);
    assertThat(nanosPerSecond * Long.MAX_VALUE).isLessThan(0L);

    // Not a valid string
    assertNotWellFormed(-1, 0, -1, 0);
  }

  public void testShardsHaveExpectedRoundTrippables() {
    // A sanity check.
    long actual = 0;
    for (long expected : generateFourByteShardsExpectedRunnables()) {
      actual += expected;
    }
    assertEquals(EXPECTED_FOUR_BYTE_ROUNDTRIPPABLE_COUNT, actual);
  }

        assertThat(bytes[0]).isEqualTo((byte) hi);
        assertThat(bytes[1]).isEqualTo((byte) lo);

        c++;
      }
    }
    assertThat(c).isEqualTo((char) 0); // sanity check
  }

  @GwtIncompatible // Chars.fromByteArray, Chars.toByteArray
  public void testByteArrayRoundTripsFails() {
    assertThrows(IllegalArgumentException.class, () -> Chars.fromByteArray(new byte[] {0x11}));

    double actualReportedFpp = bf.expectedFpp();
    assertThat(actualReportedFpp).isWithin(0.00033).of(expectedReportedFpp);
  }

  /** Sanity checking with many combinations of false positive rates and expected insertions */
  public void testBasic() {
    for (double fpr = 0.0000001; fpr < 0.1; fpr *= 10) {

    double actualReportedFpp = bf.expectedFpp();
    assertThat(actualReportedFpp).isWithin(0.00033).of(expectedReportedFpp);
  }

  /** Sanity checking with many combinations of false positive rates and expected insertions */
  public void testBasic() {
    for (double fpr = 0.0000001; fpr < 0.1; fpr *= 10) {