assertEquals(bimap1, bimap2);
    bimap2.inverse().put(Country.SWITZERLAND, Currency.FRANC);
    assertEquals(Country.SWITZERLAND, bimap2.get(Currency.FRANC));
    assertThat(bimap1.get(Currency.FRANC)).isNull();
    assertFalse(bimap2.equals(bimap1));

    /* Test that it can be empty. */
    EnumBiMap<Currency, Country> emptyBimap = EnumBiMap.create(Currency.class, Country.class);

import assertk.assertions.isFalse
import assertk.assertions.isIn
import assertk.assertions.isInstanceOf
import assertk.assertions.isNotEmpty
import assertk.assertions.isNotNull
import assertk.assertions.isNull
import assertk.assertions.isSameInstanceAs
import assertk.assertions.prop
import java.io.File
import java.io.IOException
import java.io.InterruptedIOException
import java.net.HttpURLConnection

      }
    } catch (Throwable caught) {
      assertThat(caught).isInstanceOf(IOException.class);
    }

    assertTrue(c1.isClosed());
    assertTrue(c2.isClosed());
    assertThat(c3).isNull();

    assertTrue(suppressor.suppressions.isEmpty());
  }

  public void testExceptionThrown_whileClosingLastCloseable() throws IOException {
    Closer closer = new Closer(suppressor);

      assertThat(defaultConverter.reverse().convert(123)).isEqualTo("");
      assertThat(defaultConverter.convert(null)).isNull();
      assertThat(defaultConverter.reverse().convert(null)).isNull();
    }
  }

  public void testConverterDefaultValue() {
    new ConverterDefaultValueChecker().check();
  }

  private static class VisibilityMethods {

    underlying.put("a", 1);
    Map<String, String> map = transformValues(underlying, Functions.toStringFunction());
    assertThat(map.remove("a")).isEqualTo("1");
    assertThat(map.remove("b")).isNull();
  }

  public void testTransformEqualityOfMapsWithNullValues() {
    Map<String, @Nullable String> underlying = new HashMap<>();
    underlying.put("a", null);
    underlying.put("b", "");

    underlying.put("a", 1);
    Map<String, String> map = transformValues(underlying, Functions.toStringFunction());
    assertThat(map.remove("a")).isEqualTo("1");
    assertThat(map.remove("b")).isNull();
  }

  public void testTransformEqualityOfMapsWithNullValues() {
    Map<String, @Nullable String> underlying = new HashMap<>();
    underlying.put("a", null);
    underlying.put("b", "");

import assertk.assertions.contains
import assertk.assertions.hasMessage
import assertk.assertions.isCloseTo
import assertk.assertions.isEqualTo
import assertk.assertions.isFalse
import assertk.assertions.isNull
import assertk.assertions.isTrue
import assertk.fail
import java.io.IOException
import java.net.HttpURLConnection
import java.net.SocketTimeoutException
import java.time.Duration
import java.util.Arrays

  }

  public void testGetOnlyElement_withDefault_empty_null() {
    Iterator<String> iterator = emptyIterator();
    assertThat(Iterators.<@Nullable String>getOnlyElement(iterator, null)).isNull();
  }

  public void testGetOnlyElement_withDefault_two() {
    Iterator<String> iterator = asList("foo", "bar").iterator();
    IllegalArgumentException expected =

      assertThat(urls.get(0).getAuthority()).isNull();
      assertThat(urls.get(0).getPath()).endsWith("/relative/path/to/some.jar");

      assertThat(urls.get(1)).isEqualTo(new URL("file:///absolute/path/to/some.jar"));

      assertThat(urls.get(2).getProtocol()).isEqualTo("file");
      assertThat(urls.get(2).getAuthority()).isNull();

  }

  public void testGetOnlyElement_withDefault_empty_null() {
    Iterator<String> iterator = emptyIterator();
    assertThat(Iterators.<@Nullable String>getOnlyElement(iterator, null)).isNull();
  }

  public void testGetOnlyElement_withDefault_two() {
    Iterator<String> iterator = asList("foo", "bar").iterator();
    IllegalArgumentException expected =