org.assertj.core.api

Class Assertions

java.lang.Object

org.assertj.core.api.StrictAssertions

org.assertj.core.api.Assertions

Direct Known Subclasses:

BDDAssertions

public class Assertions
extends StrictAssertions

Entry point for assertion methods for different data types. Each method in this class is a static factory for the type-specific assertion objects. The purpose of this class is to make test code more readable.

For example:

 int removed = employees.removeFired();
 assertThat(removed).isZero();

 List<Employee> newEmployees = employees.hired(TODAY);
 assertThat(newEmployees).hasSize(6);
 

The difference with StrictAssertions is that this class contains assertThat methods with interface parameter to avoid Java 8 ambiguous method error (see http://stackoverflow.com/questions/29499847/ambiguous-method-in-java-8-why).

Author:

Alex Ruiz, Yvonne Wang, David DIDIER, Ted Young, Joel Costigliola, Matthieu Baechler, Mikhail Mazursky, Nicolas François, Julien Meddah, William Delanoue, Turbo87, dorzey

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Assertions() Creates a new Assertions.

Method Summary

Modifier and Type	Method and Description
static <T> T	assertThat(AssertProvider<T> component) Delegates the creation of the Assert to the AssertProvider.assertThat() of the given component.
static AbstractCharSequenceAssert<?,? extends CharSequence>	assertThat(CharSequence actual) Creates a new instance of CharSequenceAssert.
static <T> AbstractIterableAssert<?,? extends Iterable<? extends T>,T>	assertThat(Iterable<? extends T> actual) Creates a new instance of IterableAssert.
static <T> AbstractIterableAssert<?,? extends Iterable<? extends T>,T>	assertThat(Iterator<? extends T> actual) Creates a new instance of IterableAssert.
static <T> AbstractListAssert<?,? extends List<? extends T>,T>	assertThat(List<? extends T> actual) Creates a new instance of ListAssert.
static <K,V> MapAssert<K,V>	assertThat(Map<K,V> actual) Creates a new instance of MapAssert.
static AbstractPathAssert<?>	assertThat(java.nio.file.Path actual) Creates a new instance of PathAssert
static <T extends Comparable<? super T>> AbstractComparableAssert<?,T>	assertThat(T actual) Creates a new instance of GenericComparableAssert with standard comparison semantics.
static <T extends AssertDelegateTarget> T	assertThat(T assertion) Returns the given assertion.

Methods inherited from class org.assertj.core.api.StrictAssertions

allOf, allOf, anyOf, anyOf, assertThatThrownBy, atIndex, catchThrowable, contentOf, contentOf, contentOf, contentOf, contentOf, contentOf, doesNotHave, entry, extractProperty, extractProperty, fail, fail, failBecauseExceptionWasNotThrown, filter, filter, in, linesOf, linesOf, linesOf, linesOf, linesOf, linesOf, not, not, notIn, offset, offset, registerCustomDateFormat, registerCustomDateFormat, setAllowComparingPrivateFields, setAllowExtractingPrivateFields, setLenientDateParsing, setMaxLengthForSingleLineDescription, setRemoveAssertJRelatedElementsFromStackTrace, shouldHaveThrown, tuple, useDefaultDateFormatsOnly, within, within, within, within, within, within, within, withinPercentage, withinPercentage, withinPercentage

Methods inherited from class java.lang.Object

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

Constructor Detail

Assertions

protected Assertions()

Creates a new Assertions.

Method Detail

assertThat

public static <T> T assertThat(AssertProvider<T> component)

Delegates the creation of the Assert to the AssertProvider.assertThat() of the given component.

Read the comments on AssertProvider for an example of its usage.

Parameters:

component - the component that creates its own assert

Returns:

the associated Assert of the given component

assertThat

public static AbstractCharSequenceAssert<?,? extends CharSequence> assertThat(CharSequence actual)

Creates a new instance of CharSequenceAssert.

Parameters:

actual - the actual value.

Returns:

the created assertion object.

assertThat

public static <T> AbstractIterableAssert<?,? extends Iterable<? extends T>,T> assertThat(Iterable<? extends T> actual)

Creates a new instance of IterableAssert.

Parameters:

actual - the actual value.

Returns:

the created assertion object.

assertThat

public static <T> AbstractIterableAssert<?,? extends Iterable<? extends T>,T> assertThat(Iterator<? extends T> actual)

Creates a new instance of IterableAssert.

Be aware that calls to most methods on returned IterableAssert will consume Iterator so it won't be possible to iterate over it again. Calling multiple methods on returned IterableAssert is safe as Iterator's elements are cached by IterableAssert first time Iterator is consumed.

Parameters:

actual - the actual value.

Returns:

the created assertion object.

assertThat

public static <T> AbstractListAssert<?,? extends List<? extends T>,T> assertThat(List<? extends T> actual)

Creates a new instance of ListAssert.

Parameters:

actual - the actual value.

Returns:

the created assertion object.

assertThat

public static AbstractPathAssert<?> assertThat(java.nio.file.Path actual)

Creates a new instance of PathAssert

Parameters:

actual - the path to test

Returns:

the created assertion object

assertThat

public static <K,V> MapAssert<K,V> assertThat(Map<K,V> actual)

Creates a new instance of MapAssert.

Returned type is MapAssert as it overrides method to annotate them with SafeVarargs avoiding annoying warnings.

Parameters:

actual - the actual value.

Returns:

the created assertion object.

assertThat

public static <T extends Comparable<? super T>> AbstractComparableAssert<?,T> assertThat(T actual)

Creates a new instance of GenericComparableAssert with standard comparison semantics.

Parameters:

actual - the actual value.

Returns:

the created assertion object.

assertThat

public static <T extends AssertDelegateTarget> T assertThat(T assertion)

Returns the given assertion. This method improves code readability by surrounding the given assertion with assertThat.

Consider for example the following MyButton and MyButtonAssert classes:

 public class MyButton extends JButton {

   private boolean blinking;

   public boolean isBlinking() { return this.blinking; }

   public void setBlinking(boolean blink) { this.blinking = blink; }

 }

 private static class MyButtonAssert implements AssertDelegateTarget {

   private MyButton button;
   MyButtonAssert(MyButton button) { this.button = button; }

   void isBlinking() {
     // standard assertion from core Assertions.assertThat
     assertThat(button.isBlinking()).isTrue();
   }

   void isNotBlinking() {
     // standard assertion from core Assertions.assertThat
     assertThat(button.isBlinking()).isFalse();
   }
 }
 

As MyButtonAssert implements AssertDelegateTarget, you can use assertThat(buttonAssert).isBlinking(); instead of buttonAssert.isBlinking(); to have easier to read assertions.

  @Test
 public void AssertDelegateTarget_example() {

   MyButton button = new MyButton();
   MyButtonAssert buttonAssert = new MyButtonAssert(button);

   // you can encapsulate MyButtonAssert assertions methods within assertThat
   assertThat(buttonAssert).isNotBlinking(); // same as : buttonAssert.isNotBlinking();

   button.setBlinking(true);

   assertThat(buttonAssert).isBlinking(); // same as : buttonAssert.isBlinking();
 }
 

Type Parameters:

T - the generic type of the user-defined assert.

Parameters:

assertion - the assertion to return.

Returns:

the given assertion.