tech.sirwellington.alchemy.test.junit

Class ThrowableAssertion

java.lang.Object

tech.sirwellington.alchemy.test.junit.ThrowableAssertion

@FluidAPIDesign
public final class ThrowableAssertion
extends Object

Makes it easier syntactically using Java 8 to assert an Exception is thrown by a section of code. You can also perform additional verification on the exception that is thrown.

Example:

 
 assertThrows(() -> someFunctionThatThrows())
 .isIntanceOf(RuntimeException.class)
 .hasNoCause();
 
 

Author:

SirWellington

Method Summary

Modifier and Type	Method and Description
static ThrowableAssertion	assertThrows(ExceptionOperation operation) Assert that a function throws an exception.
ThrowableAssertion	containsInMessage(String messageString) Assert that the exception contains a string in its message.
ThrowableAssertion	hasCauseInstanceOf(Class<? extends Throwable> exceptionClass) Asserts that the Exception has a cause of a particular type.
ThrowableAssertion	hasMessage(String expectedMessage) Checks to make sure the exception contains a certain message.
ThrowableAssertion	hasNoCause() Assert that the exception has no causing exception
ThrowableAssertion	isInstanceOf(Class<? extends Throwable> exceptionClass) Check that the Exception is of a particular type.

Methods inherited from class java.lang.Object

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

Method Detail

assertThrows

public static ThrowableAssertion assertThrows(ExceptionOperation operation)
                                       throws ExceptionNotThrownException

Assert that a function throws an exception.

Parameters:

operation - The Lambda function that encapsulates code you expect to throw an exception.

Returns:

Throws:

ExceptionNotThrownException - If no exception is thrown.

isInstanceOf

public ThrowableAssertion isInstanceOf(Class<? extends Throwable> exceptionClass)

Check that the Exception is of a particular type.

Parameters:

exceptionClass - The expected type of the Exception.

Returns:

hasMessage

public ThrowableAssertion hasMessage(String expectedMessage)

Checks to make sure the exception contains a certain message.

Parameters:

expectedMessage - The exact message expected

Returns:

containsInMessage

public ThrowableAssertion containsInMessage(String messageString)

Assert that the exception contains a string in its message.

Parameters:

messageString - The partial message to expected.

Returns:

hasNoCause

public ThrowableAssertion hasNoCause()

Assert that the exception has no causing exception

Returns:

hasCauseInstanceOf

public ThrowableAssertion hasCauseInstanceOf(Class<? extends Throwable> exceptionClass)

Asserts that the Exception has a cause of a particular type.

Parameters:

exceptionClass - The type expected.

Returns: