Truth 0.30

Pushing towards a 1.0 release

New Subjects

• OptionalSubject (for java.util.Optional, accessible via Truth8.assertThat(Optional<T>))
  (see details under "new extensions" below)

Changes to existing Subjects and Core classes

• Preliminary versions of "Fuzzy Equality" for doubles/floats. See DoublesSubject for
  new APIs, and we'll be updating the docs on fuzzy equality soon.

  • Subject implementers should note changes to the Service Provider Interface (SPI) for writing
    custom Subject subclasses:
    • getSubject() -> actual()
    • getDisplaySubject() -> actualAsString()
    • If you want to provide a subject-specific string representation of the type being tested, a new
      method actualCustomStringRepresentation() can be overridden. The deprecated
      getDisplaySubject() and getSubject() methods should not be overridden (and will be
      deleted in Truth 1.0. The renamed methods are final.
      actualAsString() has logic that not only consumes the string representation (default or custom)
      but also honors .named() and other contextual formatting.

• More evolution of "Fuzzy" truth - near-value approximation for certain types rather than strict
  equality is now supported by way of a "correspondence" mechanism, and the capabilities are
  being extended to many existing subjects.

  • To use:

        assertThat(actualIterable)
            .comparingElementsUsing(correspondence)
            .containsExactlyElementsIn(expectedIterable);

    Currently supports containsExactlyElementsIn(Iterable<E>), doesNotContain(E), and
    contains(E) methods. Subjects for Map, Iterable, and the Multimap types all support
    correspondence. For more detail, see the javadoc for IterableSubject.UsingCorrespondence and
    Correspondence

• .named() now supports a varargs/format construction, such as:

        assertThat(someBooleanFunction())
            .named("processed %s(%s)", foo, bar)
            .isTrue();

  This results in a more suitable error message: Not true that processed foo(bar) <false> is true as
  compared with the default message, and requires less string concatenation where that may prove
  awkward

New Extensions

• Add an extension for Java8 types, initially containing a subject forjava.util.Optional

  • Include "com.google.truth.extensions:truth-java8-extension:0.30" in your build dependencies

  • To use:

        import static com.google.common.truth.Truth8.assertThat;
        import java.util.Optional;
        public class MyTest {
          @Test public void testOptional() {
            Optional<String> o = Optional.of("Foo");
            assertThat(o).isPresent(); //succeeds
            assertThat(o).hasValue("Foo"); //succeeds
            assertThat(o).isEmpty(); // fails
          }
        }

Fixes

• Fix a missing @Nullable in AbstractVerb.that(T)
• Various cleanups of code, docs, readme, javadocs, and contribution