assertEquals("", Strings.nullToEmpty(null));
    assertEquals("", Strings.nullToEmpty(""));
    assertEquals("a", Strings.nullToEmpty("a"));
  }

  public void testEmptyToNull() {
    assertNull(Strings.emptyToNull(null));
    assertNull(Strings.emptyToNull(""));
    assertEquals("a", Strings.emptyToNull("a"));
  }

  public void testIsNullOrEmpty() {
    assertTrue(Strings.isNullOrEmpty(null));

    FreshValueGenerator generator = new FreshValueGenerator();
    assertValueAndTypeEquals(expected, generator.generateFresh(type));
    assertNull(generator.generateFresh(type));
  }

  private static void assertNotInstantiable(TypeToken<?> type) {
    assertNull(new FreshValueGenerator().generateFresh(type));
  }

  private static void assertValueAndTypeEquals(Object expected, Object actual) {

        QueryBuilder builder = queryCommand.convertTermQuery(queryContext, (TermQuery) query, 1.0f);
        if (text.startsWith("sort:")) {
            assertNull(builder);
        } else {
            logger.info("{} => {}", text, builder.toString());
            assertEquals(expectedClass, builder.getClass());

    assertThrows(NoSuchElementException.class, () -> navigableMap.firstKey());
  }

  @CollectionSize.Require(ZERO)
  public void testEmptyMapLast() {
    assertThrows(NoSuchElementException.class, () -> assertNull(navigableMap.lastKey()));
  }

  @CollectionSize.Require(ONE)
  public void testSingletonMapFirst() {
    assertEquals(a.getKey(), navigableMap.firstKey());
  }

  @CollectionSize.Require(ONE)

    String string = source.read();
    assertExpectedString(string);
  }

  public void testReadFirstLine() throws IOException {
    if (expectedLines.isEmpty()) {
      assertNull(source.readFirstLine());
    } else {
      assertEquals(expectedLines.get(0), source.readFirstLine());
    }
  }

  public void testReadLines_toList() throws IOException {

                  actualOccupiedDepth.set(monitor.getOccupiedDepth());
                } catch (Throwable t) {
                  thrown.set(t);
                }
              }
            }));
    assertNull(thrown.get());
    assertEquals(expectedIsOccupied, actualIsOccupied.get());
    assertEquals(expectedIsOccupiedByCurrentThread, actualIsOccupiedByCurrentThread.get());

                  actualOccupiedDepth.set(monitor.getOccupiedDepth());
                } catch (Throwable t) {
                  thrown.set(t);
                }
              }
            }));
    assertNull(thrown.get());
    assertEquals(expectedIsOccupied, actualIsOccupied.get());
    assertEquals(expectedIsOccupiedByCurrentThread, actualIsOccupiedByCurrentThread.get());

    assertEquals(v0(), getMap().replace(k0(), v0()));
    expectUnchanged();
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testReplace_supportedAbsent() {
    assertNull(getMap().replace(k3(), v3()));
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)

    assertEquals(v0(), getMap().replace(k0(), v0()));
    expectUnchanged();
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testReplace_supportedAbsent() {
    assertNull(getMap().replace(k3(), v3()));
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)

        assertEquals(Double.parseDouble(expected), DocumentUtil.getValue(doc, "key1", Double.class).doubleValue());

        assertNull(DocumentUtil.getValue(doc, "key2", String.class));
    }

    public void test_strings() {
        Map<String, Object> doc = new HashMap<>();
        doc.put("key1", new String[] { "aaa", "bbb" });