com.google.common.truth

Class Truth

java.lang.Object

com.google.common.truth.Truth

public final class Truth
extends Object

The primary entry point for Truth, a library for fluent test assertions.

Compare these example JUnit assertions...

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

...to their Truth equivalents...

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

Advantages of Truth:

• aligns all the "actual" values on the left
• produces more detailed failure messages
• provides richer operations (like IterableSubject.containsExactly(java.lang.Object...))

For more information about the methods in this class, see this FAQ entry.

For people extending Truth

The most common way to extend Truth is to write a custom Subject. (The other, much less common way is to write a custom FailureStrategy.) For more information, visit those types' docs.

Author:

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

Method Summary

Modifier and Type	Method and Description
static StandardSubjectBuilder	assert_() Begins a call chain with the fluent Truth API.
static <CustomSubjectBuilderT extends CustomSubjectBuilder> CustomSubjectBuilderT	assertAbout(CustomSubjectBuilder.Factory<CustomSubjectBuilderT> factory) A generic, advanced method of extension of Truth to new types, which is documented on CustomSubjectBuilder.
static <S extends Subject,T> SimpleSubjectBuilder<S,T>	assertAbout(Subject.Factory<S,T> factory) Given a factory for some Subject class, returns a builder whose that(actual) method creates instances of that class.
static BigDecimalSubject	assertThat(BigDecimal actual)
static BooleanSubject	assertThat(Boolean actual)
static PrimitiveBooleanArraySubject	assertThat(boolean[] actual)
static PrimitiveByteArraySubject	assertThat(byte[] actual)
static PrimitiveCharArraySubject	assertThat(char[] actual)
static ClassSubject	assertThat(Class<?> actual)
static DoubleSubject	assertThat(Double actual)
static PrimitiveDoubleArraySubject	assertThat(double[] actual)
static FloatSubject	assertThat(Float actual)
static PrimitiveFloatArraySubject	assertThat(float[] actual)
static PrimitiveIntArraySubject	assertThat(int[] actual)
static IntegerSubject	assertThat(Integer actual)
static IterableSubject	assertThat(Iterable<?> actual)
static LongSubject	assertThat(Long actual)
static PrimitiveLongArraySubject	assertThat(long[] actual)
static MapSubject	assertThat(Map<?,?> actual)
static MultimapSubject	assertThat(Multimap<?,?> actual)
static MultisetSubject	assertThat(Multiset<?> actual)
static Subject	assertThat(Object actual)
static GuavaOptionalSubject	assertThat(Optional<?> actual)
static PrimitiveShortArraySubject	assertThat(short[] actual)
static StringSubject	assertThat(String actual)
static <T extends Comparable<?>> ComparableSubject<T>	assertThat(T actual)
static <T> ObjectArraySubject<T>	assertThat(T[] actual)
static TableSubject	assertThat(Table<?,?,?> actual)
static ThrowableSubject	assertThat(Throwable actual)
static StandardSubjectBuilder	assertWithMessage(String messageToPrepend) Begins an assertion that, if it fails, will prepend the given message to the failure message.
static StandardSubjectBuilder	assertWithMessage(String format, Object... args) Begins an assertion that, if it fails, will prepend the given message to the failure message.

Methods inherited from class java.lang.Object

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

Method Detail

assert_

public static StandardSubjectBuilder assert_()

Begins a call chain with the fluent Truth API. If the check made by the chain fails, it will throw AssertionError.

assertWithMessage

public static StandardSubjectBuilder assertWithMessage(String messageToPrepend)

Begins an assertion that, if it fails, will prepend the given message to the failure message.

This method is a shortcut for assert_().withMessage(...).

To set a message when using a custom subject, use assertWithMessage(...).about(...), as discussed in this FAQ entry.

assertWithMessage

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

Begins an assertion that, if it fails, will prepend the given message to the failure message.

Note: the arguments will be substituted into the format template using Strings.lenientFormat. Note this only supports the %s specifier.

This method is a shortcut for assert_().withMessage(...).

To set a message when using a custom subject, use assertWithMessage(...).about(...), as discussed in this FAQ entry.

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,T> SimpleSubjectBuilder<S,T> assertAbout(Subject.Factory<S,T> factory)

Given a factory for some Subject class, returns a builder whose that(actual) method creates instances of that class.

assertAbout

public static <CustomSubjectBuilderT extends CustomSubjectBuilder> CustomSubjectBuilderT assertAbout(CustomSubjectBuilder.Factory<CustomSubjectBuilderT> factory)

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

assertThat

public static <T extends Comparable<?>> ComparableSubject<T> assertThat(@NullableDecl
                                                                        T actual)

assertThat

public static BigDecimalSubject assertThat(@NullableDecl
                                           BigDecimal actual)

assertThat

public static Subject assertThat(@NullableDecl
                                 Object actual)

assertThat

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

assertThat

public static ThrowableSubject assertThat(@NullableDecl
                                          Throwable actual)

assertThat

public static LongSubject assertThat(@NullableDecl
                                     Long actual)

assertThat

public static DoubleSubject assertThat(@NullableDecl
                                       Double actual)

assertThat

public static FloatSubject assertThat(@NullableDecl
                                      Float actual)

assertThat

public static IntegerSubject assertThat(@NullableDecl
                                        Integer actual)

assertThat

public static BooleanSubject assertThat(@NullableDecl
                                        Boolean actual)

assertThat

public static StringSubject assertThat(@NullableDecl
                                       String actual)

assertThat

public static IterableSubject assertThat(@NullableDecl
                                         Iterable<?> actual)

assertThat

public static <T> ObjectArraySubject<T> assertThat(@NullableDecl
                                                   T[] actual)

assertThat

public static PrimitiveBooleanArraySubject assertThat(@NullableDecl
                                                      boolean[] actual)

assertThat

public static PrimitiveShortArraySubject assertThat(@NullableDecl
                                                    short[] actual)

assertThat

public static PrimitiveIntArraySubject assertThat(@NullableDecl
                                                  int[] actual)

assertThat

public static PrimitiveLongArraySubject assertThat(@NullableDecl
                                                   long[] actual)

assertThat

public static PrimitiveByteArraySubject assertThat(@NullableDecl
                                                   byte[] actual)

assertThat

public static PrimitiveCharArraySubject assertThat(@NullableDecl
                                                   char[] actual)

assertThat

public static PrimitiveFloatArraySubject assertThat(@NullableDecl
                                                    float[] actual)

assertThat

public static PrimitiveDoubleArraySubject assertThat(@NullableDecl
                                                     double[] actual)

assertThat

public static GuavaOptionalSubject assertThat(@NullableDecl
                                              Optional<?> actual)

assertThat

public static MapSubject assertThat(@NullableDecl
                                    Map<?,?> actual)

assertThat

public static MultimapSubject assertThat(@NullableDecl
                                         Multimap<?,?> actual)

assertThat

public static MultisetSubject assertThat(@NullableDecl
                                         Multiset<?> actual)

assertThat

public static TableSubject assertThat(@NullableDecl
                                      Table<?,?,?> actual)