org.opendaylight.persistence.util.test

Class ThrowableTester

java.lang.Object

org.opendaylight.persistence.util.test.ThrowableTester

public final class ThrowableTester
extends Object

Throwable tester.

This class does not offer a message parameter to display when the test fails. The purpose of the test should be clear by the test name, the utilities in this class deals with expected throwables and proper error messages will be displayed if the assertion fails.

Note: Throwable isn't generally caught. Throwable is the superclass to Exception and Error. Errors are generally things which a normal application wouldn't and shouldn't catch, so just use Exception unless you have a specific reason to use Throwable. In this case ThrowableTester checks whether an expected Throwable is actually thrown.

Note that JUnit already offers a way to assert expected exceptions, however for complex setups the exception may come from an unexpected source hiding a problem. Example:

 // Good usage of the JUnit annotation 
 @Test(expected = NullPointerException.class)
 public void test() {
     ClassUnderTest testable = ...;
     testable.methodExpectingToThrowException();
 }
 
 // Dangerous usage of the JUnit annotation
 @Test(expected = NullPointerException.class)
 public void test() {
     setUpOperation_1;
     ...                 // If any of the setup operations throw a NullPointerException the test will pass hiding a problem
     setUpOperation_n;
     ClassUnderTest testable = ...;
     testable.methodExpectingToThrowException();
 }
 
 // Alternative using ThrowableTester
 @Test
 public void test() {
     setUpOperation_1;
     ...                 // If any of the setup operations throw a NullPointerException the test will fail uncovering a problem
     setUpOperation_n;
     final ClassUnderTest testable = ...;
         
     ThrowableTester.testThrows(NullPointerException.class, new Instruction(){
         @Override
         public void execute() throws Throwable {
             testable.methodExpectingToThrowException();
         }
     });
 }
 

Author:

Fabiel Zuniga, Nachiket Abhyankar

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ThrowableTester.Instruction Instruction.
static interface	ThrowableTester.Validator<E extends Throwable> Throwable validator.

Method Summary

Methods

Modifier and Type	Method and Description
static <T extends Throwable> void	assertAnyThrowableType(Class<T> expected, Throwable actual) Asserts that an exception is of (or a subclass of) the given expected type.
static <T extends Throwable> void	assertThrowableType(Class<T> expected, Throwable actual) Asserts that an exception is exactly of the given expected type.
static <T extends Throwable> void	testThrows(Class<T> expectedThrowable, ThrowableTester.Instruction instruction) Executes an instruction verifying a Throwable of the expected type is actually thrown.
static <T extends Throwable> void	testThrows(Class<T> expectedThrowable, ThrowableTester.Instruction instruction, ThrowableTester.Validator<T> throwableValidator) Executes an instruction verifying a Throwable of the expected type is actually thrown.
static <T extends Throwable> void	testThrowsAny(Class<T> expectedThrowable, ThrowableTester.Instruction instruction) Executes an instruction verifying a Throwable of (or a subclass of) the expected type is actually thrown.
static <T extends Throwable> void	testThrowsAny(Class<T> expectedThrowable, ThrowableTester.Instruction instruction, ThrowableTester.Validator<T> throwableValidator) Executes an instruction verifying a Throwable of (or a subclass of) the expected type is actually thrown.

Methods inherited from class java.lang.Object

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

Method Detail

assertAnyThrowableType

public static <T extends Throwable> void assertAnyThrowableType(Class<T> expected,
                                                Throwable actual)

Asserts that an exception is of (or a subclass of) the given expected type.

Parameters:

expected - expected Throwable type

actual - actual Throwable

assertThrowableType

public static <T extends Throwable> void assertThrowableType(Class<T> expected,
                                             Throwable actual)

Asserts that an exception is exactly of the given expected type.

Parameters:

expected - expected Throwable type

actual - actual Throwable

testThrowsAny

public static <T extends Throwable> void testThrowsAny(Class<T> expectedThrowable,
                                       ThrowableTester.Instruction instruction)

Executes an instruction verifying a Throwable of (or a subclass of) the expected type is actually thrown.

Parameters:

expectedThrowable - expected Throwable

instruction - instruction to execute

testThrowsAny

public static <T extends Throwable> void testThrowsAny(Class<T> expectedThrowable,
                                       ThrowableTester.Instruction instruction,
                                       ThrowableTester.Validator<T> throwableValidator)

Executes an instruction verifying a Throwable of (or a subclass of) the expected type is actually thrown.

Parameters:

expectedThrowable - expected Throwable

instruction - instruction to execute

throwableValidator - validator is used to do additional inspection to the error

testThrows

public static <T extends Throwable> void testThrows(Class<T> expectedThrowable,
                                    ThrowableTester.Instruction instruction)

Executes an instruction verifying a Throwable of the expected type is actually thrown.

Parameters:

expectedThrowable - expected Throwable

instruction - instruction to execute

testThrows

public static <T extends Throwable> void testThrows(Class<T> expectedThrowable,
                                    ThrowableTester.Instruction instruction,
                                    ThrowableTester.Validator<T> throwableValidator)

Executes an instruction verifying a Throwable of the expected type is actually thrown.

Parameters:

expectedThrowable - expected Throwable

instruction - instruction to execute

throwableValidator - validator is used to do additional inspection to the error