com.google.common.truth

Class Subject<S extends Subject<S,T>,T>

java.lang.Object

com.google.common.truth.Subject<S,T>

Type Parameters:

S - the self-type, allowing this-returning methods to avoid needing subclassing

T - the type of the object being tested by this Subject

Direct Known Subclasses:

AtomicLongMapSubject, BooleanSubject, ClassSubject, ComparableSubject, DefaultSubject, GuavaOptionalSubject, IterableOfProtosSubject, IterableSubject, LiteProtoSubject, MapSubject, MapWithProtoValuesSubject, MultimapSubject, MultimapWithProtoValuesSubject, ObjectArraySubject, OptionalDoubleSubject, OptionalIntSubject, OptionalLongSubject, OptionalSubject, PrimitiveBooleanArraySubject, PrimitiveByteArraySubject, PrimitiveCharArraySubject, PrimitiveDoubleArraySubject, PrimitiveFloatArraySubject, PrimitiveIntArraySubject, PrimitiveLongArraySubject, PrimitiveShortArraySubject, Re2jSubjects.Re2jStringSubject, StreamSubject, TableSubject, ThrowableSubject

public class Subject<S extends Subject<S,T>,T>
extends Object

A Subject in Truth fits into the assertion fluent chain, taking the place of the "subject of the test". For instance, in assertThat("foo").isNotNull(), Truth#assertThat(String) returns a StringSubject which wraps the actual value itself, providing a hook for methods which test propositions about the actual value.

Custom sub-types of Subject provide type-appropriate methods which can then provide more suitable error messages than the traditional assertions may provide.

Author:

David Saff, Christian Gruber

Field Summary

Fields

Modifier and Type	Field and Description
protected FailureStrategy	failureStrategy

Constructor Summary

Constructors

Constructor and Description
Subject(FailureStrategy failureStrategy, T actual)

Method Summary

Modifier and Type	Method and Description
protected T	actual() Returns the unedited, unformatted raw actual value.
protected String	actualAsString() Returns a string representation of the actual value.
protected String	actualCustomStringRepresentation() Supplies the direct string representation of the actual value to other methods which may prefix or otherwise position it in an error message.
protected TestVerb	check() A convenience for implementers of Subject subclasses to use other truth Subject wrappers within their own propositional logic.
boolean	equals(Object o) Deprecated. Object.equals(Object) is not supported on Truth subjects. If you meant to test object equality between an expected and the actual value, use isEqualTo(Object) instead.
protected void	fail(String proposition) Reports a failure constructing a message from a simple verb.
protected void	fail(String verb, Object... messageParts) Assembles a failure message and passes such to the FailureStrategy
protected void	fail(String verb, Object other) Assembles a failure message and passes such to the FailureStrategy.
protected void	failWithBadResults(String verb, Object expected, String failVerb, Object actual) Assembles a failure message and passes it to the FailureStrategy
protected void	failWithCustomSubject(String verb, Object expected, Object actual) Assembles a failure message with an alternative representation of the wrapped subject and passes it to the FailureStrategy
protected void	failWithoutActual(String proposition) Assembles a failure message without a given subject and passes it to the FailureStrategy
protected void	failWithoutSubject(String proposition) Deprecated. Use failWithoutActual(String)
protected void	failWithRawMessage(String message, Object... parameters) Passes through a failure message verbatim.
protected String	getDisplaySubject() Deprecated. Prefer #actualAsString() for display-formatted access to the subject.
protected T	getSubject() Deprecated. Prefer #actual() for direct access to the subject.
int	hashCode() Deprecated. Object.hashCode() is not supported on Truth subjects.
protected TestVerb	ignoreCheck() A convenience for implementers of Subject subclasses that use other truth Subject wrappers within their own propositional logic and sometimes need to short-circuit those subjects because the assertion chain has already failed.
protected String	internalCustomName() An internal method used to obtain the value set by named(String, Object...).
void	isAnyOf(Object first, Object second, Object... rest) Fails unless the subject is equal to any of the given elements.
void	isEqualTo(Object other) Fails if the subject is not equal to the given object.
void	isIn(Iterable<?> iterable) Fails unless the subject is equal to any element in the given iterable.
void	isInstanceOf(Class<?> clazz) Fails if the subject is not an instance of the given class.
void	isNoneOf(Object first, Object second, Object... rest) Fails if the subject is equal to any of the given elements.
void	isNotEqualTo(Object other) Fails if the subject is equal to the given object.
void	isNotIn(Iterable<?> iterable) Fails if the subject is equal to any element in the given iterable.
void	isNotInstanceOf(Class<?> clazz) Fails if the subject is an instance of the given class.
void	isNotNull() Fails if the subject is null.
void	isNotSameAs(Object other) Fails if the subject is the same instance as the given object.
void	isNull() Fails if the subject is not null.
void	isSameAs(Object other) Fails if the subject is not the same instance as the given object.
S	named(String format, Object... args) Adds a prefix to the subject, when it is displayed in error messages.

Methods inherited from class java.lang.Object

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

Field Detail

failureStrategy

protected final FailureStrategy failureStrategy

Constructor Detail

Subject

public Subject(FailureStrategy failureStrategy,
               @Nullable
               T actual)

Method Detail

internalCustomName

protected String internalCustomName()

An internal method used to obtain the value set by named(String, Object...).

named

public S named(String format,
               Object... args)

Adds a prefix to the subject, when it is displayed in error messages. This is especially useful in the context of types that have no helpful toString() representation, e.g. boolean. Writing assertThat(foo).named("foo").isTrue(); then results in a more reasonable error message.

named() takes a format template and argument objects which will be substituted into the template, similar to String.format(String, Object...), the chief difference being that extra parameters (for which there are no template variables) will be appended to the resulting string in brackets. Additionally, this only supports the %s template variable type.

isNull

public void isNull()

Fails if the subject is not null.

isNotNull

public void isNotNull()

Fails if the subject is null.

isEqualTo

public void isEqualTo(@Nullable
                      Object other)

Fails if the subject is not equal to the given object. For the purposes of this comparison, two objects are equal if any of the following is true:

• they are equal according to Objects.equal(java.lang.Object, java.lang.Object)
• they are arrays and are considered equal by the appropriate Arrays#equals overload
• they are boxed integer types (Byte, Short, Character, Integer, or Long) and they are numerically equal when converted to Long.

isNotEqualTo

public void isNotEqualTo(@Nullable
                         Object other)

Fails if the subject is equal to the given object. The meaning of equality is the same as for the isEqualTo(java.lang.Object) method.

isSameAs

public void isSameAs(@Nullable
                     Object other)

Fails if the subject is not the same instance as the given object.

isNotSameAs

public void isNotSameAs(@Nullable
                        Object other)

Fails if the subject is the same instance as the given object.

isInstanceOf

public void isInstanceOf(Class<?> clazz)

Fails if the subject is not an instance of the given class.

isNotInstanceOf

public void isNotInstanceOf(Class<?> clazz)

Fails if the subject is an instance of the given class.

isIn

public void isIn(Iterable<?> iterable)

Fails unless the subject is equal to any element in the given iterable.

isAnyOf

public void isAnyOf(@Nullable
                    Object first,
                    @Nullable
                    Object second,
                    @Nullable
                    Object... rest)

Fails unless the subject is equal to any of the given elements.

isNotIn

public void isNotIn(Iterable<?> iterable)

Fails if the subject is equal to any element in the given iterable.

isNoneOf

public void isNoneOf(@Nullable
                     Object first,
                     @Nullable
                     Object second,
                     @Nullable
                     Object... rest)

Fails if the subject is equal to any of the given elements.

getSubject

@Deprecated
protected T getSubject()

Deprecated. Prefer #actual() for direct access to the subject.

actual

protected final T actual()

Returns the unedited, unformatted raw actual value.

getDisplaySubject

@Deprecated
protected String getDisplaySubject()

Deprecated. Prefer #actualAsString() for display-formatted access to the subject.

actualAsString

protected final String actualAsString()

Returns a string representation of the actual value. This will either be the toString() of the value or a prefixed "name" along with the string representation.

actualCustomStringRepresentation

protected String actualCustomStringRepresentation()

Supplies the direct string representation of the actual value to other methods which may prefix or otherwise position it in an error message. This should only be overridden to provide an improved string representation of the value under test, as it would appear in any given error message, and should not be used for additional prefixing.

Subjects should override this with care.

By default, this returns String.ValueOf(getActualValue()).

check

protected TestVerb check()

A convenience for implementers of Subject subclasses to use other truth Subject wrappers within their own propositional logic.

ignoreCheck

protected final TestVerb ignoreCheck()

A convenience for implementers of Subject subclasses that use other truth Subject wrappers within their own propositional logic and sometimes need to short-circuit those subjects because the assertion chain has already failed. In such cases it may still be necessary to return a Subject instance even though any subsequent assertions are meaningless. Use this method to return subjects that will never report failures.

fail

protected final void fail(String proposition)

Reports a failure constructing a message from a simple verb.

Parameters:

proposition - the proposition being asserted

fail

protected final void fail(String verb,
                          Object other)

Assembles a failure message and passes such to the FailureStrategy. Also performs disambiguation if the subject and other have the same toString()'s.

Parameters:

verb - the proposition being asserted

other - the value against which the subject is compared

fail

protected final void fail(String verb,
                          Object... messageParts)

Assembles a failure message and passes such to the FailureStrategy

Parameters:

verb - the proposition being asserted

messageParts - the expectations against which the subject is compared

failWithBadResults

protected final void failWithBadResults(String verb,
                                        Object expected,
                                        String failVerb,
                                        Object actual)

Assembles a failure message and passes it to the FailureStrategy

Parameters:

verb - the proposition being asserted

expected - the expectations against which the subject is compared

failVerb - the failure of the proposition being asserted

actual - the actual value the subject was compared against

failWithCustomSubject

protected final void failWithCustomSubject(String verb,
                                           Object expected,
                                           Object actual)

Assembles a failure message with an alternative representation of the wrapped subject and passes it to the FailureStrategy

Parameters:

verb - the proposition being asserted

expected - the expected value of the proposition

actual - the custom representation of the subject to be reported in the failure.

failWithoutSubject

@Deprecated
protected final void failWithoutSubject(String proposition)

Deprecated. Use failWithoutActual(String)

failWithoutActual

protected final void failWithoutActual(String proposition)

Assembles a failure message without a given subject and passes it to the FailureStrategy

Parameters:

proposition - the proposition being asserted

failWithRawMessage

protected void failWithRawMessage(String message,
                                  Object... parameters)

Passes through a failure message verbatim. Used for Subject subclasses which need to provide alternate language for more fit-to-purpose error messages.

Parameters:

message - the message template to be passed to the failure. Note, this method only guarantees to process %s tokens. It is not guaranteed to be compatible with String.format(). Any other formatting desired (such as floats or scientific notation) should be performed before the method call and the formatted value passed in as a string.

parameters - the object parameters which will be applied to the message template.

equals

@Deprecated
public final boolean equals(@Nullable
                                        Object o)

Deprecated. Object.equals(Object) is not supported on Truth subjects. If you meant to test object equality between an expected and the actual value, use isEqualTo(Object) instead.

Overrides:

equals in class Object

Throws:

UnsupportedOperationException - always

hashCode

@Deprecated
public final int hashCode()

Deprecated. Object.hashCode() is not supported on Truth subjects.

Overrides:

hashCode in class Object

Throws:

UnsupportedOperationException - always