Post on 09-May-2015
description
Bad Tests, Good Tests
Tomek Kaczanowski
http://twitter.com/#!/devops_borat
Tomek Kaczanowski
• Developer• Team lead• Blogger
• http://kaczanowscy.pl/tomek
• Book author• http://practicalunittesting.com
• Trainer• Interested? Contact me!
• kaczanowski.tomek@gmail.com
• Trainings in Vienna? Sure!
Before we begin
• All of the examples are real but were:• obfuscated
• to protect the innocents :)
• truncated
• imagine much more complex domain objects
• Asking questions is allowed• ...but being smarter than me is not ;)
Who writes tests?
What about the ROI?
http://ripper1331.deviantart.com
http://ripper1331.deviantart.com
http://ripper1331.deviantart.com
http://twitter.com/#!/devops_borat
Survey is show junior devopsare still believein Tooth Fairy, Santa Claus anddocumentation
http://ripper1331.deviantart.com
http://twitter.com/#!/devops_borat
Survey is show junior devopsare still believein Tooth Fairy, Santa Claus anddocumentation
If you think good designis expensive,you should look at the cost of bad design.
Dr Ralph Speth, CEO Jaguar
Tests help to achieve quality
Not sure when I saw this picture – probably in GOOS?
What happens if we do it wrong?
• Angry clients• Depressed developers
http://www.joshcanhelp.com
When I started out with unit tests, I was enthralled with the promise of ease and security that they would bring to my projects. In practice, however, the theory of sustainable software through unit tests started to break down. This difficulty continued to build up, until I finally threw my head back in anger and declared that "Unit Tests have become more trouble than they are worth."
Llewellyn Falco and Michael Kennedy, Develop Mentor August 09
http://chrispiascik.com/daily-drawings/express-yourself/
write the right test
write the right test
write this test right
Ancient times
public void testAddChunks() {System.out.println("*************************************");System.out.println("testAddChunks() ... ");ChunkMap cm = new ChunkMap(3);cm.addChunk(new Chunk("chunk"));
List testList = cm.getChunks("chunk",null);
if (testList.isEmpty())fail("there should be at least one list!");
Chunk chunk = cm.getActualChunk("chunk",null);if (chunk.getElements().isEmpty())
fail("there should be at least one element!");if (cm.getFinalChunkNr() != 1)
fail("there should be at least one chunk!");// iterate actual chunkfor (Iterator it = chunk.getElements().iterator();
it.hasNext();) {Element element = (Element) it.next();System.out.println("Element: " + element);
}showChunks(cm);System.out.println("testAddChunks() OK ");
} Courtesy of @bocytko
public void testSimple() {IData data = null;IFormat format = null;LinkedList<String> attr = new LinkedList<String>();attr.add("A");attr.add("B");
try {format = new SimpleFormat("A");data.setAmount(Amount.TEN);data.setAttributes(attr);IResult result = format.execute();System.out.println(result.size());Iterator iter = result.iterator();while (iter.hasNext()) {
IResult r = (IResult) iter.next(); System.out.println(r.getMessage());
...}catch (Exception e) {
fail();}
}Courtesy of @bocytko
What has happened? Well, it failed...public void testSimple() {
IData data = null;IFormat format = null;LinkedList<String> attr = new LinkedList<String>();attr.add("A");attr.add("B");
try {format = new SimpleFormat("A");data.setAmount(Amount.TEN);data.setAttributes(attr);IResult result = format.execute();System.out.println(result.size());Iterator iter = result.iterator();while (iter.hasNext()) {
IResult r = (IResult) iter.next(); System.out.println(r.getMessage());
...}
catch (Exception e) {fail();
}}
data is null - ready or not, NPE is coming!
Courtesy of @bocytko
Success is not an option...
/** * Method testFailure. */public void testFailure() { try { Message message = new Message(null,true); fail(); } catch(Exception ex) { ExceptionHandler.log(ExceptionLevel.ANY,ex); fail(); }}
Courtesy of @bocytko
No smoke without testsclass SystemAdminSmokeTest extends GroovyTestCase {
void testSmoke() { def ds = new org.h2.jdbcx.JdbcDataSource( URL: 'jdbc:h2:mem:test;DB_CLOSE_DELAY=-1;MODE=Oracle', user: 'sa', password: '') def jpaProperties = new Properties() jpaProperties.setProperty( 'hibernate.cache.use_second_level_cache', 'false') jpaProperties.setProperty( 'hibernate.cache.use_query_cache', 'false') def emf = new LocalContainerEntityManagerFactoryBean( dataSource: ds, persistenceUnitName: 'my-domain', jpaVendorAdapter: new HibernateJpaVendorAdapter( database: Database.H2, showSql: true, generateDdl: true), jpaProperties: jpaProperties)
…some more code below}
No smoke without testsclass SystemAdminSmokeTest extends GroovyTestCase {
void testSmoke() {// do not remove below code// def ds = new org.h2.jdbcx.JdbcDataSource(// URL: 'jdbc:h2:mem:test;DB_CLOSE_DELAY=-1;MODE=Oracle',// user: 'sa', password: '')//// def jpaProperties = new Properties()// jpaProperties.setProperty(// 'hibernate.cache.use_second_level_cache', 'false')// jpaProperties.setProperty(// 'hibernate.cache.use_query_cache', 'false')//// def emf = new LocalContainerEntityManagerFactoryBean(// dataSource: ds, persistenceUnitName: 'my-domain',// jpaVendorAdapter: new HibernateJpaVendorAdapter(// database: Database.H2, showSql: true,// generateDdl: true), jpaProperties: jpaProperties)
…some more code below, all commented out :(}
Let's follow the leader!
@Testpublic class ExampleTest {
public void testExample() {assertTrue(true);
}}
Uh-oh, I feel lonely...
@Testpublic class ExampleTest {
public void testExample() {assertTrue(true);
}}
Conclusions
• Automation!• Running• Manual verification is evil
• Do not live with broken window• If you don't fix things no one else will!• It is a full time job!
• You should be informed why your test failed• Master your tools
• …at least learn the basics!
Mocks & Co.
@Testpublic void shouldGetTrafficTrend() { //given TrafficTrendProvider trafficTrendProvider
= mock(TrafficTrendProvider.class); Report report = new Report(null, "", 1, 2, 3,
BigDecimal.ONE, BigDecimal.ONE, 1); TrafficTrend trafficTrend = new TrafficTrend(report, report,
new Date(), new Date(), new Date(), new Date()); given(trafficTrendProvider.getTrafficTrend())
.willReturn(trafficTrend); TrafficService service
= new TrafficService(trafficTrendProvider);
//when TrafficTrend result = service.getTrafficTrend();
//then assertThat(result).isEqualTo(trafficTrend);}
Use of the real objects obscures the test
@Testpublic void shouldGetTrafficTrend() { //given TrafficTrendProvider trafficTrendProvider
= mock(TrafficTrendProvider.class); TrafficTrend trafficTrend = mock(TrafficTrend.class); given(trafficTrendProvider.getTrafficTrend())
.willReturn(trafficTrend);
TrafficService service = new TrafficService(trafficTrendProvider);
//when TrafficTrend result = service.getTrafficTrend();
//then assertThat(result).isEqualTo(trafficTrend);}
Mock'em All!
@Test
public void shouldAddTimeZoneToModelAndView() {
//given
UserFacade userFacade = mock(UserFacade.class);
ModelAndView modelAndView = mock(ModelAndView.class);
given(userFacade.getTimezone()).willReturn("timezone X");
//when
new UserDataInterceptor(userFacade)
.postHandle(null, null, null, modelAndView);
//then
verify(modelAndView).addObject("timezone", "timezone X");
}
Mock'em All!
@Test
public void shouldAddTimeZoneToModelAndView() {
//given
UserFacade userFacade = mock(UserFacade.class);
ModelAndView modelAndView = mock(ModelAndView.class);
given(userFacade.getTimezone()).willReturn("timezone X");
//when
new UserDataInterceptor(userFacade)
.postHandle(null, null, null, modelAndView);
//then
verify(modelAndView).addObject("timezone", "timezone X");
}
ModelAndView from SpringMVC – a mere container for data, without any behaviour
Do not test interactions if not needed
@Test
public void shouldAddTimeZoneToModelAndView() {
//given
UserFacade userFacade = mock(UserFacade.class);
ModelAndView modelAndView = new ModelAndView();
given(userFacade.getTimezone()).willReturn("timezone X");
//when
new UserDataInterceptor(userFacade)
.postHandle(null, null, null, modelAndView);
//then
assertThat(modelAndView).contains("timezone", "timezone X");
}
a pseudocode but that is what we mean
public class Util {
public String getUrl(User user, String timestamp) {String name = user.getFullName();String url = baseUrl
+"name="+URLEncoder.encode(name, "UTF-8")+"×tamp="+timestamp;
return url; }
public String getUrl(User user) {Date date = new Date();Long time = date.getTime()/1000; //convert ms to secondsString timestamp = time.toString();return getUrl(user, timestamp);
}}
Developer wants to checkwhether timestamp is added to the URL when this method is used
public class Util {
public String getUrl(User user, String timestamp) {...
}
public String getUrl(User user) {...
}}
Developer wants to checkwhether timestamp is added to the URL when this method is used
public class Util {
public String getUrl(User user, String timestamp) {...
}
public String getUrl(User user) {...
}}
@Testpublic void shouldUseTimestampMethod() {
//givenUtil util = new Util();Util spyUtil = Mockito.spy(util);
//whenspyUtil.getUrl(user);
//thenverify(spyUtil).getUrl(eq(user), anyString());
}
Developer wants to checkwhether timestamp is added to the URL when this method is used
Bad design → bad tests
Dependency Injection will save us
@Test
public void shouldGenerateURLWithTimestamp() {
//given
TimeProvider timeProvider = mock(TimeProvider.class);
Util util = new Util(timeProvider);
given(timeProvider.getTime()).willReturn("12345");
util.set(timeProvider);
//when
String url = util.getUrl(user);
//then
assertThat(url).contains("timestamp=12345");
}
Single Responsibility Principle
A test should have one and only one reason to fail.
Testing two things at once@DataProviderpublic Object[][] data() {
return new Object[][] { {"48", true}, {"+48", true}, {"++48", true}, {"+48503", true}, {"+4", false},{"++4", false}, {"", false},{null, false}, {" ", false}, };
}
@Test(dataProvider = "data")public void testQueryVerification(String query, boolean expected) {
assertEquals(expected, FieldVerifier.isValidQuery(query));}
Testing two things at once@DataProviderpublic Object[][] data() {
return new Object[][] { {"48", true}, {"+48", true}, {"++48", true}, {"+48503", true}, {"+4", false},{"++4", false}, {"", false},{null, false}, {" ", false}, };
}
@Test(dataProvider = "data")public void testQueryVerification(String query, boolean expected) {
assertEquals(expected, FieldVerifier.isValidQuery(query));}
testQueryVerification1() {assertEquals(true, FieldVerifier.isValidQuery(„48”));
}testQueryVerification2() {
assertEquals(true, FieldVerifier.isValidQuery(„+48”));}testQueryVerification3() {
assertEquals(true, FieldVerifier.isValidQuery(„++48”));}testQueryVerification4() {
assertEquals(true, FieldVerifier.isValidQuery(„+48503”));}...
Testing two things at once@DataProviderpublic Object[][] data() {
return new Object[][] { {"48", true}, {"+48", true}, {"++48", true}, {"+48503", true}, {"+4", false},{"++4", false}, {"", false},{null, false}, {" ", false}, };
}
@Test(dataProvider = "data")public void testQueryVerification(String query, boolean expected) {
assertEquals(expected, FieldVerifier.isValidQuery(query));}
Concentrate on one feature@DataProviderpublic Object[][] validQueries() {
return new Object[][] { {"48"}, {"48123"}, {"+48"}, {"++48"}, {"+48503"}};
}
@Test(dataProvider = "validQueries")public void shouldRecognizeValidQueries(String validQuery) {
assertTrue(FieldVerifier.isValidQuery(validQuery));}
@DataProviderpublic Object[][] invalidQueries() { return new Object[][] {
{"+4"}, {"++4"}, {""}, {null}, {" "} };}
@Test(dataProvider = "invalidQueries")public void shouldRejectInvalidQueries(String invalidQuery) {
assertFalse(FieldVerifier.isValidQuery(invalidQuery));}
“And”
@Test
public void shouldReturnRedirectViewAndSendEmail() {
//given
given(bindingResult.hasErrors()).willReturn(false);
given(userData.toEntity()).willReturn(user);
given(userService.saveNewUser(eq(userData.toEntity())))
.willReturn(user);
//when
ModelAndView userRegisterResult = userRegisterController
.registerUser(userData, bindingResult, request);
//then
assertThat(userRegisterResult.getViewName())
.isEqualTo("redirect:/signin");
verify(mailSender).sendRegistrationInfo(user);
}
One feature at a time
@Test
public void shouldRedirectToSigninPageWhenRegistrationSuceeded () {
...
}
@Test
public void shouldNotifyAboutNewUserRegistration() {
...
}
Hint: forget about methods
Readability is the king
variables
@DataProvider
public static Object[][] usersPermissions() {
return new Object[][]{
{"user_1", Permission.READ},
{"user_1", Permission.WRITE},
{"user_1", Permission.REMOVE},
{"user_2", Permission.WRITE},
{"user_2", Permission.READ},
{"user_3", Permission.READ}
};
}
Who the heck is “user_2” ?
@DataProvider
public static Object[][] usersPermissions() {
return new Object[][]{
{"user_1", Permission.READ},
{"user_1", Permission.WRITE},
{"user_1", Permission.REMOVE},
{"user_2", Permission.WRITE},
{"user_2", Permission.READ},
{"user_3", Permission.READ}
};
}
Who the heck is “user_2”?!
Ah, logged user can read and write...
@DataProvider
public static Object[][] usersPermissions() {
return new Object[][]{
{ADMIN, Permission.READ},
{ADMIN, Permission.WRITE},
{ADMIN, Permission.REMOVE},
{LOGGED, Permission.WRITE},
{LOGGED, Permission.READ},
{GUEST, Permission.READ}
};
}
domain1, domain2, domain3, ...
domain1, domain2, domain3, ...
domain1, domain2, domain3, ...
Do not make me learn the API!
server = new MockServer(responseMap, true,
new URL(SERVER_ROOT).getPort(), false);
Do not make me learn the API!
server = new MockServer(responseMap, true,
new URL(SERVER_ROOT).getPort(), false);
private static final boolean RESPONSE_IS_A_FILE = true;
private static final boolean NO_SSL = false;
server = new MockServer(responseMap, RESPONSE_IS_A_FILE,
new URL(SERVER_ROOT).getPort(), NO_SSL);
Do not make me learn the API!
server = new MockServer(responseMap, true,
new URL(SERVER_ROOT).getPort(), false);
server = createFileNonSSLMockServer(responseMap);
Do not make me learn the API!
server = new MockServer(responseMap, true,
new URL(SERVER_ROOT).getPort(), false);
server = new MockServerBuilder()
.withResponse(responseMap)
.withResponseType(FILE)
.withUrl(SERVER_ROOT)
.withoutSsl().create();
server = MockServerBuilder
.createFileNoSSLServer(responseMap, SERVER_ROOT);
Readability is the king
test method names
Test methods names are important
• When test fails• Relation to focused tests
What is it all about?
@Test
public void testOperation() {
configureRequest("/validate")
rc = new RequestContext(parser, request)
assert rc.getConnector() == null
assert rc.getOperation().equals("validate")
}
“should” is better than “test”
• shouldRejectInvalidRequests()• shouldSaveNewUserToDatabase()• constructorShouldFailWithNegativePrice()• shouldReturnOnlyUsersWithGivenName()
• testOperation()• testQuery()• testConstructor()• testFindUsersWithFilter()
“should” is better than “test”
• Starting test method names with “should” steers you in the right direction.
• “test” prefix makes your test method a limitless bag where you throw everything worth testing
http://www.greenerideal.com/
http://jochopra.blogspot.com/
Test methods names are important@Testpublic void testQuery(){ when(q.getResultList()).thenReturn(null); assertNull(dao.findByQuery(Transaction.class, q, false)); assertNull(dao.findByQuery(Operator.class, q, false)); assertNull(dao.findByQuery(null, null, false));
List result = new LinkedList(); when(q.getResultList()).thenReturn(result); assertEquals(dao.findByQuery(Transaction.class, q, false), result); assertEquals(dao.findByQuery(Operator.class, q, false), result); assertEquals(dao.findByQuery(null, null, false), null);
when(q.getSingleResult()).thenReturn(null); assertEquals(dao.findByQuery(Transaction.class, q, true).size(), 0); assertEquals(dao.findByQuery(Operator.class, q, true).size(), 0); assertEquals(dao.findByQuery(null, null, true), null);
when(q.getSingleResult()).thenReturn(t); assertSame(dao.findByQuery(Transaction.class, q, true).get(0), t); when(q.getSingleResult()).thenReturn(o); assertSame(dao.findByQuery(Operator.class, q, true).get(0), o); when(q.getSingleResult()).thenReturn(null); assertSame(dao.findByQuery(null, null, true), null);}
Test methods names are important@Testpublic void shouldReturnNullListWhenDaoReturnsNull { when(q.getResultList()).thenReturn(null); assertNull(dao.findByQuery(Transaction.class, q, false)); assertNull(dao.findByQuery(Operator.class, q, false)); assertNull(dao.findByQuery(null, null, false));}public void shouldReturnEmptyListWhenDaoReturnsIt { List result = new LinkedList(); when(q.getResultList()).thenReturn(result); assertEquals(dao.findByQuery(Transaction.class, q, false), result); assertEquals(dao.findByQuery(Operator.class, q, false), result); assertEquals(dao.findByQuery(null, null, false), null);}public void shouldReturnNullSingleResultWhenDaoReturnsNull { when(q.getSingleResult()).thenReturn(null); assertEquals(dao.findByQuery(Transaction.class, q, true).size(), 0); assertEquals(dao.findByQuery(Operator.class, q, true).size(), 0); assertEquals(dao.findByQuery(null, null, true), null);}public void shouldReturnSingleResultReturnedByDao { when(q.getSingleResult()).thenReturn(t); assertSame(dao.findByQuery(Transaction.class, q, true).get(0), t); when(q.getSingleResult()).thenReturn(o); assertSame(dao.findByQuery(Operator.class, q, true).get(0), o); when(q.getSingleResult()).thenReturn(null); assertSame(dao.findByQuery(null, null, true), null);}
Assertions
public void shouldPreDeployApplication() {// givenArtifact artifact = mock(Artifact.class);when(artifact.getFileName()).thenReturn("war-artifact-2.0.war");ServerConfiguration config
= new ServerConfiguration(ADDRESS, USER, KEY_FILE, TOMCAT_PATH, TEMP_PATH);Tomcat tomcat = new Tomcat(HTTP_TOMCAT_URL, config);String destDir = new File(".").getCanonicalPath() + SLASH + "target" + SLASH;new File(destDir).mkdirs();
// whentomcat.preDeploy(artifact, new FakeWar(WAR_FILE_LENGTH));
//thenJSch jsch = new JSch();jsch.addIdentity(KEY_FILE);Session session = jsch.getSession(USER, ADDRESS, 22);session.setConfig("StrictHostKeyChecking", "no");session.connect();
Channel channel = session.openChannel("sftp");session.setServerAliveInterval(92000);channel.connect();ChannelSftp sftpChannel = (ChannelSftp) channel;
sftpChannel.get(TEMP_PATH + SLASH + artifact.getFileName(), destDir);sftpChannel.exit();
session.disconnect();
File downloadedFile = new File(destDir, artifact.getFileName());
assertThat(downloadedFile).exists().hasSize(WAR_FILE_LENGTH);}
Just say it
public void shouldPreDeployApplication() {// givenArtifact artifact = mock(Artifact.class);when(artifact.getFileName())
.thenReturn(ARTIFACT_FILE_NAME);ServerConfiguration config
= new ServerConfiguration(ADDRESS, USER, KEY_FILE, TOMCAT_PATH, TEMP_PATH);
Tomcat tomcat = new Tomcat(HTTP_TOMCAT_URL, config);
// whentomcat.preDeploy(artifact, new FakeWar(WAR_FILE_LENGTH));
// thenSSHServerAssert.assertThat(ARTIFACT_FILE_NAME)
.existsOnServer(tomcat).hasSize(WAR_FILE_LENGTH);}
Just say it
public void shouldPreDeployApplication() {// givenArtifact artifact = mock(Artifact.class);when(artifact.getFileName())
.thenReturn(ARTIFACT_FILE_NAME);ServerConfiguration config
= new ServerConfiguration(ADDRESS, USER, KEY_FILE, TOMCAT_PATH, TEMP_PATH);
Tomcat tomcat = new Tomcat(HTTP_TOMCAT_URL, config);
// whentomcat.preDeploy(artifact, new FakeWar(WAR_FILE_LENGTH));
// thenassertThatFileIsOnServer(ARTIFACT_FILE_NAME,
Tomcat, WAR_FILE_LENGTH);}
WHY NOT USEWHY NOT CREATE
A PRIVATE ASSERTION METHOD?
Assertions repeated in many tests
@Testpublic void testChargeInRetryingState() throws Exception { // given
TxDTO request = createTxDTO(RequestType.CHARGE);AndroidTransaction androidTransaction = ...
request.setTransaction(androidTransaction);
// when final TxDTO txDTO = processor.processRequest(request);
// thenList<AndroidTransactionStep> steps
= new ArrayList<>(androidTransaction.getSteps());AndroidTransactionStep lastStep = steps.get(steps.size() - 1);
assertEquals(lastStep.getTransactionState(), CHARGED_PENDING);assertEquals(txDTO.getResultCode(), CHARGED);
}
Assertions repeated in many tests
@Testpublic void testChargeInRetryingState() throws Exception { // given
TxDTO request = createTxDTO(RequestType.CHARGE);AndroidTransaction androidTransaction = ...
request.setTransaction(androidTransaction);
// when final TxDTO txDTO = processor.processRequest(request);
// thenList<AndroidTransactionStep> steps
= new ArrayList<>(androidTransaction.getSteps());AndroidTransactionStep lastStep = steps.get(steps.size() - 1);
assertEquals(lastStep.getTransactionState(), CHARGED_PENDING);assertEquals(txDTO.getResultCode(), CHARGED);
}
WHY NOT CREATEA PRIVATE ASSERTION METHOD?
Asserting using private methods
@Testpublic void testChargeInRetryingState() throws Exception { // given
TxDTO request = createTxDTO(RequestType.CHARGE);AndroidTransaction androidTransaction = ...
// when final TxDTO txDTO = processor.processRequest(request);
// then assertState(request, androidTransaction,
CHARGED, CHARGE_PENDING, AS_ANDROID_TX_STATE, ClientMessage.SUCCESS, ResultCode.SUCCESS);}
assertState(TxDTO txDTO, AndroidTransaction androidTransaction,AndroidTransactionState expectedAndroidState,
AndroidTransactionState expectedPreviousAndroidState, ExtendedState expectedState, String expectedClientStatus, ResultCode expectedRequestResultCode) { final List<AndroidTransactionStep> steps
= new ArrayList<>(androidTransaction.getTransactionSteps()); final boolean checkPreviousStep = expectedAndroidState != null; assertTrue(steps.size() >= (checkPreviousStep ? 3 : 2));
if (checkPreviousStep) { AndroidTransactionStep lastStep = steps.get(steps.size() - 2); assertEquals(lastStep.getTransactionState(),
expectedPreviousAndroidState); }
final AndroidTransactionStep lastStep = steps.get(steps.size() - 1); assertEquals(lastStep.getTransactionState(), expectedAndroidState); assertEquals(lastStep.getMessage(), expectedClientStatus);
assertEquals(txDTO.getResultCode(), expectedRequestResultCode); assertEquals(androidTransaction.getState(), expectedAndroidState); assertEquals(androidTransaction.getExtendedState(), expectedState);
if (expectedClientStatus == null) { verifyZeroInteractions(client); }}
Custom assertions to the rescue
@Test
public void testChargeInRetryingState() throws Exception {
// given
TxDTO request = createTxDTO(CHARGE);
AndroidTransaction androidTransaction = ...
// when
final TxDTO txDTO = processor.processRequest(request);
// then
assertThat(androidTransaction).hasState(CHARGED)
.hasMessage(ClientMessage.SUCCESS)
.hasPreviousState(CHARGE_PENDING)
.hasExtendedState(null);
assertEquals(txDTO.getResultCode(), ResultCode.SUCCESS);
}
Asserting implementation details
public void invalidTxShouldBeCanceled() {
...
String fileContent =
FileUtils.getContentOfFile("response.csv");
assertTrue(fileContent.contains(
"CANCEL,123,123cancel,billing_id_123_cancel,SUCCESS,"));
}
Asserting implementation details
public void invalidTxShouldBeCanceled() {
...
String fileContent =
FileUtils.getContentOfFile("response.csv");
assertTrue(fileContent.contains(
"CANCEL,123,123cancel,billing_id_123_cancel,SUCCESS,"));
}
public void invalidTxShouldBeCanceled() {
...
String fileContent =
FileUtils.getContentOfFile("response.csv");
TxDTOAssert.assertThat(fileContent)
.hasTransaction("123cancel").withResultCode(SUCCESS);
}
Know your tools
• Unit testing framework• Use of temporary file rule
• Listeners
• Concurrency
• @Before/@After
• Parametrized tests
• Test dependencies
• Additional libraries
• Hamcrest, FEST, Mockito, catch-exception, awaitility, JUnitParams, tempus-fugit, …
• Build tool• Parallel execution
• CI
• IDE• Templates
• Shortcuts
Expected exceptions
@Test(expected=IndexOutOfBoundsException.class)
public void shouldThrowExceptionGettingElementOutsideTheList() {
MyList<Integer> list = new MyList<Integer>();
list.add(0);
list.add(1);
list.get(2);
}
Expected exceptions
@Test(expected=IndexOutOfBoundsException.class)
public void shouldThrowExceptionGettingElementOutsideTheList() {
MyList<Integer> list = new MyList<Integer>();
list.add(0);
list.add(1);
list.get(2);
}
@Test
public void shouldThrowExceptionGettingtElementOutsideTheList() {
MyList<Integer> list = new MyList<Integer>();
list.add(0);
list.add(1);
catchException(list).get(2);
assertThat(caughtException())
.isExactlyInstanceOf(IndexOutOfBoundsException.class);
}
http://code.google.com/p/catch-exception/
Awaitility
@Testpublic void updatesCustomerStatus() throws Exception {
// Publish an asynchronous event: publishEvent(updateCustomerStatusEvent);
// Awaitility lets you wait until // the asynchronous operation completes:
await().atMost(5, SECONDS).until(costumerStatusIsUpdated());
...}
http://code.google.com/p/awaitility/
What do you really want to test?
@Test
public void shouldAddAUser() {
User user = new User();
userService.save(user);
assertEquals(dao.getNbOfUsers(), 1);
}
You wanted to see that the number increased
@Test
public void shouldAddAUser() {
int nb = dao.getNbOfUsers();
User user = new User();
userService.save(user);
assertEquals(dao.getNbOfUsers(), nb + 1);
}
Because:1) This is closer to what you wanted to test2) There is no assumption about the database “users” table being empty
Asking for troubles...
LoggingPropertyConfigurator configurator = mock(...);
BaseServletContextListener baseServletContextListener =
= new BaseServletContextListener(configurator)
@Test public void shouldLoadConfigProperties() {
baseServletContextListener.contextInitialized();
verify(configurator).configure(any(Properties.class));
}
@Test(expected = LoggingInitialisationException.class)
public void shouldThrowExceptionIfCantLoadConfiguration() {
System.setProperty("logConfig", "nonExistingFile");
baseServletContextListener.contextInitialized();
}
Should load some default config
Should load this specific file
Asking for troubles...
LoggingPropertyConfigurator configurator = mock(...);BaseServletContextListener baseServletContextListener =
= new BaseServletContextListener(configurator)
@Test public void shouldLoadConfigProperties() {baseServletContextListener.contextInitialized();verify(configurator).configure(any(Properties.class));
}
@Test(expected = LoggingInitialisationException.class)public void shouldThrowExceptionIfCantLoadConfiguration() {
System.setProperty("logConfig", "nonExistingFile");baseServletContextListener.contextInitialized();
}
@Beforepublic void cleanSystemProperties() {
...}
Ceremony
@Testpublic void shouldBeAdministrator() { //given User user = new Administrator();
//when boolean administrator = user.isAdministrator(); boolean advertiser = user.isAdvertiser(); boolean domainer = user.isDomainer();
//then assertThat(administrator).isTrue(); assertThat(advertiser).isFalse(); assertThat(domainer).isFalse();}
Ceremony
@Testpublic void shouldBeAdministrator() { User user = new Administrator();
assertThat(user.isAdministrator()).isTrue(); assertThat(user.isAdvertiser()).isFalse(); assertThat(user.isDomainer()).isFalse();}
private static final int PER_PAGE = 10;
@Testpublic void shouldGiveOffsetZeroWhenOnZeroPage() { Pager pager = new Pager(PER_PAGE);
assertThat(pager.getOffset()).isEqualTo(0);}
@Testpublic void shouldIncreaseOffsetWhenGoingToPageOne() { Pager pager = new Pager(PER_PAGE);
pager.goToNextPage();
assertThat(pager.getOffset()).isEqualTo(PER_PAGE);}
private static final int PER_PAGE = 10;
@Testpublic void shouldGiveOffsetZeroWhenOnZeroPage() { Pager pager = new Pager(PER_PAGE);
assertThat(pager.getOffset()).isEqualTo(0);}
@Testpublic void shouldIncreaseOffsetWhenGoingToPageOne() { Pager pager = new Pager(PER_PAGE);
pager.goToNextPage();
assertThat(pager.getOffset()).isEqualTo(PER_PAGE);}
public void goToNextPage() { this.offset = +perPage;}
Test-last?
• makes people not write tests at all• makes people do only happy path testing• tests reflect the implementation
Treat tests as the first class citizens
• do it everyday or forget about it
• use the right tool for the job
• and learn to use it!
• do not live with broken windows
• respect KISS, SRP, DRY (?)
• write good code, and you will also write good tests
• or rather write good tests and you will get good code for free
• code review your tests
• do more than happy path testing
• do not make the reader learn the API, make it obvious
• bad names lead to bad tests
• make tests readable using matchers, builders and good names
• test behaviour not methods
• be pragmatic about the tests you write
• TDD always?
• what is the best way to test it? unit/integration/end-to-end ?
• automate!
• always concentrate on what is worth testing
• ask yourself questions like: 'is it really important that X should send message Y to Z?'
• use the front door – state testing before interaction testing (mocks)
You can learn more about writing high quality tests by reading my book – „Practical Unit Testing”.
You can also participate in writing of my new (free!) e-book devoted to bad and good tests.
Thank you!