Class Expect

java.lang.Object

com.google.common.truth.StandardSubjectBuilder

com.google.common.truth.Expect

All Implemented Interfaces:

TestRule

@GwtIncompatible("JUnit4")
public final class Expect
extends StandardSubjectBuilder
implements TestRule

A TestRule that batches up all failures encountered during a test, and reports them all together at the end (similar to ErrorCollector). It is also useful for making assertions from other threads or from within callbacks whose exceptions would be swallowed or logged, rather than propagated out to fail the test. (AssertJ has a similar feature called "soft assertions"; however, soft assertions are not safe for concurrent use.)

Usage:

@Rule public final Expect expect = Expect.create();

...

  expect.that(results).containsExactly(...);
  expect.that(errors).isEmpty();

If both of the assertions above fail, the test will fail with an exception that contains information about both.

Expect may be used concurrently from multiple threads. However, multithreaded tests still require care:

• Expect has no way of knowing when all your other test threads are done. It simply checks for failures when the main thread finishes executing the test method. Thus, you must ensure that any background threads complete their assertions before then, or your test may ignore their results.
• Assertion failures are not the only exceptions that may occur in other threads. For maximum safety, multithreaded tests should check for such exceptions regardless of whether they use Expect. (Typically, this means calling get() on any Future returned by a method like executor.submit(...). It might also include checking for unexpected log messages or reading metrics that count failures.) If your tests already check for exceptions from a thread, then that will cover any exception from plain assertThat.

To record failures for the purpose of testing that an assertion fails when it should, see ExpectFailure.

For more on this class, see the documentation page.

Method Summary

Modifier and Type	Method	Description
Statement	apply(Statement base, Description description)
static Expect	create()	Creates a new instance.
boolean	hasFailures()

Methods inherited from class StandardSubjectBuilder

about, about, fail, forCustomFailureStrategy, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, that, withMessage, withMessage

Modifier and Type	Method	Description
final <CustomSubjectBuilderT extends CustomSubjectBuilder> CustomSubjectBuilderT	about(CustomSubjectBuilder.Factory<CustomSubjectBuilderT> factory)	A generic, advanced method of extension of Truth to new types, which is documented on CustomSubjectBuilder.
final <S extends Subject, A> SimpleSubjectBuilder<S,A>	about(Subject.Factory<S,A> factory)	Given a factory for some Subject class, returns a builder whose that(actual) method creates instances of that class.
final void	fail()	Reports a failure.
static StandardSubjectBuilder	forCustomFailureStrategy(FailureStrategy strategy)	Returns a new instance that invokes the given FailureStrategy when a check fails.
final PrimitiveBooleanArraySubject	that(boolean @Nullable [] actual)
final PrimitiveByteArraySubject	that(byte @Nullable [] actual)
final PrimitiveCharArraySubject	that(char @Nullable [] actual)
final PrimitiveDoubleArraySubject	that(double @Nullable [] actual)
final PrimitiveFloatArraySubject	that(float @Nullable [] actual)
final PrimitiveIntArraySubject	that(int @Nullable [] actual)
final PrimitiveLongArraySubject	that(long @Nullable [] actual)
final PrimitiveShortArraySubject	that(short @Nullable [] actual)
final <ComparableT extends Comparable<?>> ComparableSubject<ComparableT>	that(@Nullable ComparableT actual)
final GuavaOptionalSubject	that(@Nullable Optional<?> actual)
final MultimapSubject	that(@Nullable Multimap<?,?> actual)
final MultisetSubject	that(@Nullable Multiset<?> actual)
final TableSubject	that(@Nullable Table<?,?,?> actual)
final BooleanSubject	that(@Nullable Boolean actual)
final ClassSubject	that(@Nullable Class<?> actual)
final DoubleSubject	that(@Nullable Double actual)
final FloatSubject	that(@Nullable Float actual)
final IntegerSubject	that(@Nullable Integer actual)
final IterableSubject	that(@Nullable Iterable<?> actual)
final LongSubject	that(@Nullable Long actual)
final Subject	that(@Nullable Object actual)
final StringSubject	that(@Nullable String actual)
final ThrowableSubject	that(@Nullable Throwable actual)
final BigDecimalSubject	that(@Nullable BigDecimal actual)
final PathSubject	that(@Nullable Path actual)
final MapSubject	that(@Nullable Map<?,?> actual)
final OptionalSubject	that(@Nullable Optional<?> actual)
final OptionalDoubleSubject	that(@Nullable OptionalDouble actual)
final OptionalIntSubject	that(@Nullable OptionalInt actual)
final OptionalLongSubject	that(@Nullable OptionalLong actual)
final IntStreamSubject	that(@Nullable IntStream actual)
final LongStreamSubject	that(@Nullable LongStream actual)
final StreamSubject	that(@Nullable Stream<?> actual)
final <T extends @Nullable Object> ObjectArraySubject<T>	that(T @Nullable [] actual)
final StandardSubjectBuilder	withMessage(@Nullable String message)	Returns a new instance that will output the given message before the main failure message.
final StandardSubjectBuilder	withMessage(String format, @Nullable Object... args)	Returns a new instance that will output the given message before the main failure message.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

create

public static Expect create()

Creates a new instance.

hasFailures

public boolean hasFailures()

apply

public Statement apply(Statement base,
 Description description)

Specified by:

apply in interface TestRule