com.google.common.truth

Class Truth

java.lang.Object

com.google.common.truth.Truth

public final class Truth
extends Object

Truth - a proposition framework for tests, supporting JUnit style assertion and assumption semantics in a fluent style.

Truth is the simplest entry point class. A developer can statically import the assertThat() method to get easy access to the library's capabilities. Then, instead of writing:

   
   Assert.assertEquals(a, b);
   Assert.assertTrue(c);
   Assert.assertTrue(d.contains(a));
   Assert.assertTrue(d.contains(a) && d.contains(b));
   Assert.assertTrue(d.contains(a) || d.contains(b) || d.contains(c));

one would write:

   
   assertThat(a).isEqualTo(b);
   assertThat(c).isTrue();
   assertThat(d).contains(a);
   assertThat(d).containsAllOf(a, b);
   assertThat(d).containsAnyOf(a, b, c);

Tests should be easier to read, and flow more clearly.

Often, tests assert a relationship between a value produced by the test (the "actual" value) and some reference value (the "expected" value). It is strongly recommended that the actual value is made the subject of the assertion. For example:

   
   assertThat(actual).isEqualTo(expected);  // recommended
   assertThat(expected).isEqualTo(actual);  // not recommended
   assertThat(actual).isIn(expectedPossibilities);  // recommended
   assertThat(expectedPossibilities).contains(actual);  // not recommended

Author:

David Saff, Christian Gruber (cgruber@israfil.net)

Field Summary

Fields

Modifier and Type	Field and Description
static FailureStrategy	THROW_ASSERTION_ERROR

Method Summary

Modifier and Type	Method and Description
static TestVerb	assert_()
static <V extends AbstractDelegatedVerb<V>> V	assertAbout(DelegatedVerbFactory<V> factory) A generic, advanced method of extension of Truth to new types, which is documented on DelegatedVerbFactory.
static <S extends Subject<S,T>,T> AbstractVerb.DelegatedVerb<S,T>	assertAbout(SubjectFactory<S,T> factory) The recommended method of extension of Truth to new types, which is documented in com.google.common.truth.delegation.DelegationTest.
static AtomicLongMapSubject	assertThat(com.google.common.util.concurrent.AtomicLongMap<?> target)
static BigDecimalSubject	assertThat(BigDecimal target)
static BooleanSubject	assertThat(Boolean target)
static PrimitiveBooleanArraySubject	assertThat(boolean[] target)
static PrimitiveByteArraySubject	assertThat(byte[] target)
static PrimitiveCharArraySubject	assertThat(char[] target)
static ClassSubject	assertThat(Class<?> target)
static DoubleSubject	assertThat(Double target)
static PrimitiveDoubleArraySubject	assertThat(double[] target)
static FloatSubject	assertThat(Float target)
static PrimitiveFloatArraySubject	assertThat(float[] target)
static PrimitiveIntArraySubject	assertThat(int[] target)
static IntegerSubject	assertThat(Integer target)
static IterableSubject	assertThat(Iterable<?> target)
static ListMultimapSubject	assertThat(com.google.common.collect.ListMultimap<?,?> target)
static LongSubject	assertThat(Long target)
static PrimitiveLongArraySubject	assertThat(long[] target)
static MapSubject	assertThat(Map<?,?> target)
static MultimapSubject	assertThat(com.google.common.collect.Multimap<?,?> target)
static MultisetSubject	assertThat(com.google.common.collect.Multiset<?> target)
static Subject<DefaultSubject,Object>	assertThat(Object target)
static GuavaOptionalSubject	assertThat(com.google.common.base.Optional<?> target)
static SetMultimapSubject	assertThat(com.google.common.collect.SetMultimap<?,?> target)
static PrimitiveShortArraySubject	assertThat(short[] target)
static SortedMapSubject	assertThat(SortedMap<?,?> target)
static SortedSetSubject	assertThat(SortedSet<?> target)
static StringSubject	assertThat(String target)
static <T extends Comparable<?>> ComparableSubject<?,T>	assertThat(T target)
static <T> ObjectArraySubject<T>	assertThat(T[] target)
static TableSubject	assertThat(com.google.common.collect.Table<?,?,?> target)
static ThrowableSubject	assertThat(Throwable target)
static TestVerb	assertWithMessage(String messageToPrepend) Returns a TestVerb that will prepend the given message to the failure message in the event of a test failure.
static TestVerb	assertWithMessage(String format, Object... args) Returns a TestVerb that will prepend the formatted message using the specified arguments to the failure message in the event of a test failure.

Methods inherited from class java.lang.Object

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

Field Detail

THROW_ASSERTION_ERROR

public static final FailureStrategy THROW_ASSERTION_ERROR

Method Detail

assert_

public static TestVerb assert_()

assertWithMessage

public static TestVerb assertWithMessage(String messageToPrepend)

Returns a TestVerb that will prepend the given message to the failure message in the event of a test failure.

assertWithMessage

public static TestVerb assertWithMessage(String format,
                                         Object... args)

Returns a TestVerb that will prepend the formatted message using the specified arguments to the failure message in the event of a test failure.

Note: The failure message template string only supports the "%s" specifier, not the full range of Formatter specifiers.

Throws:

IllegalArgumentException - if the number of placeholders in the format string does not equal the number of given arguments

assertAbout

public static <S extends Subject<S,T>,T> AbstractVerb.DelegatedVerb<S,T> assertAbout(SubjectFactory<S,T> factory)

The recommended method of extension of Truth to new types, which is documented in com.google.common.truth.delegation.DelegationTest.

Parameters:

factory - a SubjectFactory implementation

Returns:

A custom verb for the type returned by the SubjectFactory

assertAbout

public static <V extends AbstractDelegatedVerb<V>> V assertAbout(DelegatedVerbFactory<V> factory)

A generic, advanced method of extension of Truth to new types, which is documented on DelegatedVerbFactory. Extension creators should prefer SubjectFactory if possible.

Type Parameters:

V - the type of AbstractDelegatedVerb to return

Parameters:

factory - a DelegatedVerbFactory<V> implementation

Returns:

A custom verb of type <V>

assertThat

public static <T extends Comparable<?>> ComparableSubject<?,T> assertThat(@Nullable
                                                                          T target)

assertThat

public static BigDecimalSubject assertThat(@Nullable
                                           BigDecimal target)

assertThat

public static Subject<DefaultSubject,Object> assertThat(@Nullable
                                                        Object target)

assertThat

@GwtIncompatible(value="ClassSubject.java")
public static ClassSubject assertThat(@Nullable
                                                                                  Class<?> target)

assertThat

public static ThrowableSubject assertThat(@Nullable
                                          Throwable target)

assertThat

public static LongSubject assertThat(@Nullable
                                     Long target)

assertThat

public static DoubleSubject assertThat(@Nullable
                                       Double target)

assertThat

public static FloatSubject assertThat(@Nullable
                                      Float target)

assertThat

public static IntegerSubject assertThat(@Nullable
                                        Integer target)

assertThat

public static BooleanSubject assertThat(@Nullable
                                        Boolean target)

assertThat

public static StringSubject assertThat(@Nullable
                                       String target)

assertThat

public static IterableSubject assertThat(@Nullable
                                         Iterable<?> target)

assertThat

public static SortedSetSubject assertThat(@Nullable
                                          SortedSet<?> target)

assertThat

public static <T> ObjectArraySubject<T> assertThat(@Nullable
                                                   T[] target)

assertThat

public static PrimitiveBooleanArraySubject assertThat(@Nullable
                                                      boolean[] target)

assertThat

public static PrimitiveShortArraySubject assertThat(@Nullable
                                                    short[] target)

assertThat

public static PrimitiveIntArraySubject assertThat(@Nullable
                                                  int[] target)

assertThat

public static PrimitiveLongArraySubject assertThat(@Nullable
                                                   long[] target)

assertThat

public static PrimitiveByteArraySubject assertThat(@Nullable
                                                   byte[] target)

assertThat

public static PrimitiveCharArraySubject assertThat(@Nullable
                                                   char[] target)

assertThat

public static PrimitiveFloatArraySubject assertThat(@Nullable
                                                    float[] target)

assertThat

public static PrimitiveDoubleArraySubject assertThat(@Nullable
                                                     double[] target)

assertThat

public static GuavaOptionalSubject assertThat(@Nullable
                                              com.google.common.base.Optional<?> target)

assertThat

public static MapSubject assertThat(@Nullable
                                    Map<?,?> target)

assertThat

public static SortedMapSubject assertThat(@Nullable
                                          SortedMap<?,?> target)

assertThat

public static MultimapSubject assertThat(@Nullable
                                         com.google.common.collect.Multimap<?,?> target)

assertThat

public static ListMultimapSubject assertThat(@Nullable
                                             com.google.common.collect.ListMultimap<?,?> target)

assertThat

public static SetMultimapSubject assertThat(@Nullable
                                            com.google.common.collect.SetMultimap<?,?> target)

assertThat

public static MultisetSubject assertThat(@Nullable
                                         com.google.common.collect.Multiset<?> target)

assertThat

public static TableSubject assertThat(@Nullable
                                      com.google.common.collect.Table<?,?,?> target)

assertThat

public static AtomicLongMapSubject assertThat(@Nullable
                                              com.google.common.util.concurrent.AtomicLongMap<?> target)