junit detect if a test is the only one run - java

I have a test like this:
#Test public void testInfinite() {
while (true) {runSomeOtherTest();waitForSomeSignal();}
We have a spring context which takes a while to initialize - and with the above test and hotswapping - it means I can debug changes in seconds rather than waiting for a restart.
However, obviously checking this into the CI system is a bit of a problem, and of course something I've accidentally done several times. I'm wondering if it's possible (without changing the testrunner, because we are already using a custom one, that's hard to modify) to determine if it's the only test running. eg I want to be able to say
#Test public void testInfinite() {
if (!testIsTheOnlyTestWhichWillBeRun()) return; ...
So, bottom line - what I'm looking for is that if I right click on exactly that test and say run, in the IDE - it will do that - in all other cases - eg I right click and run the whole class - or I do it from gradle, or from CI - the test does nothing and just returns immediately.

You can evaluate a System property:
#Test public void testInfinite() {
if (!"true".equals(System.getProperty("junit.runloop"))) {
return;
}
}
In your IDE/local run, you can then run the test with -Djunit.runloop=true.
To not polute the test cases themselves, you could write a JUnit rule that does this:
public class TestInfinite implements TestRule {
#Override
public Statement apply(Statement base, Description description) {
return new Statement() {
public void evaluate() throws Throwable {
do {
base.evaluate();
} while ("true".equals(System.getProperty("junit.runloop")));
}
};
}
}
So in your test, you can attach them:
public class YourTest {
#Rule public TestInfinite = new TestInfinite();
#Test public void testInfinite() {
// this will be run once if property is not set,
// in an endless loop if it is
}
}

Related

How to embed every test in a wrapper logic?

Given the requirement that every junit test have to run in the following wrapper:
#Test
public void testFooBar() {
SpecialLogic.runWith(new SpecialLogic("blah", "foo", ANYTHING), () -> {
// my test
});
}
I am trying to avoid adding SpecialLogic.runWith(...) for each test.
Is there any possibility by using #BeforeEach or any other way?
Otherwise, there is much of duplicated code:
#Test
public void testFooBar_2() {
SpecialLogic.runWith(new SpecialLogic("blah", "foo", ANYTHING), () -> {
// my test logic 2
});
}
#Test
public void testFooBar_3() {
SpecialLogic.runWith(new SpecialLogic("blah", "foo", ANYTHING), () -> {
// my test logic 3
});
}
There are two ways of doing this:
Write your custom Runner, all the tests will have to run with this runner.
This may be inappropriate if you already use another runner (say for spring or mockito)
Write your own Rule. The rule is a little bit newer way of doing what you've asked for,
and it doesn't "occupy" the slot of a runner which can be only one.
public final class SampleRule implements TestRule {
#Override public Statement apply(final Statement base,
final Description description) {
return new Statement() {
#Override public void evaluate() throws Throwable {
// do your stuff before actually running the test
try {
base.evaluate(); // This line actually runs the test.
} finally {
// do your stuff after running a test
}
}
};}}
Here is one of numerous guides for writing Rules:
Looks like you should implement your own TestRunner to wrap your custom logic around each test method call. There is an article over at Baelung explaining how this works.
#Before and #After? It won't use closures but should be functionally the same.
https://junit.org/junit4/javadoc/latest/org/junit/Before.html
https://junit.org/junit4/javadoc/latest/org/junit/After.html

Marking test methods with #Test(dependsOnMethods=..) testNG annotation make them not to execute

I've got a problem in my production test suite runs.
testng.xml has set up to run test suite in multithreaded environment using custom listener. As result there are several driver instances that are running separately and in parallel, with each test.
Last time suite started failing and I noticed strange behavior:
Each test in each test method which has dependsOnMethods in its #Test annotation do not execute. Driver just skipps them, and does not execute #AfterTest methods as result.
Or, I suppose It does not skip them, it does not report to depend methods that "login" method is done and they can go on and execute.
But i have no idea why is it happening
Smth like this:
#BeforeClass
protected void beforeClassInit(){
setUp(///);
}
#Test
public void login() {
//login activities
}
#Test(dependsOnMethods = "login")
public void createSmth() {
///
}
#Test(dependsOnMethods = "createService")
public void deleteSmth() {
///
}
#AfterClass(alwaysRun = true)
protected void afterClass() {
shutDown();
}
See in your code,
#BeforeClass
protected void beforeClassInit(){
setUp(///);
}
#Test
public void login() {
//login activities
}
#Test(dependsOnMethods = "login", alwaysRun=true)
public void createSmth() {
///
}
#Test(dependsOnMethods = "createSmth", alwaysRun=true)
public void deleteSmth() {
///
}
#AfterClass(alwaysRun = true)
protected void afterClass() {
shutDown();
}
createSmth and deleteSmth always run even if dependant method will get fail to execute. Before and after class annotation will be run before/after the first/last test method in the current class is invoked.
#BeforeClass when multiple tests need to share the same computationally expensive setup code. #BeforeClass will be executed only once.
It works even if you will run using testng.xml in parellel
The problem was in testng logic.
Through tons of experiments it was defined, that TestNG always runs dependent methods in the end of parallel run.
Means, i.e. you have 3 Test Classes:
Test1.java
Test2.java
Test3.java
and each has some test methods.
TestNG suite contains that 3 classes will run each non-dependent method from those classes, than come back and finish run of those dependent methods which left.
Crazy behavior, but looks that's it/

Integration test before others

I have a bunch of integration tests that need to have a database populated before running. This task takes about 30 minutes, so it is not feasible to run it before every test.
I'm using junit and I'd like to be able to annotate this one class with something so that it runs and completes before the others start. Is this possible?
(most of the annotations I found only work on methods, e.g. #Rule)
I've done this in the past by adding setup and teardown functions to the individual test classes, annotated with #BeforeClass and #AfterClass.
#BeforeClass
public static void setupBeforeClass() {
DatabasePopulater.populate();
}
#AfterClass
public static void tearDownAfterClass() {
DatabasePopulater.dePopulate();
}
If more than one test class requires the same setup to be done, the setup function can do a kind of reference counting to make sure they only do their work the first time it's called:
public class DatabasePopulater {
AtomicInteger invocations = new AtomicInteger();
....
public static void populate() {
if (0 == ivocations.getAndIncrement()) {
// Actually populate DB
}
}
public static void dePopulate() {
if (0 == ivocations.decrementAndGet()) {
// Actually clear DB
}
}
If you are using something like ant/gradle to execute the test suite, you could separate out the db population into a standalone java program and then have a depends="populateDB" on the junit task.

Dealing with System.exit(0) in JUnit tests

I am implementing some tests for an existing Java Swing application, so that I can safely refactor and extend the code without breaking anything. I started with some unit tests in JUnit, since that seems the simplest way to get started, but now my priority is to create some end-to-end tests to exercise the application as a whole.
I am starting the application afresh in each test by putting each test method in a separate test case, and using the fork="yes" option in Ant's junit task. However, some of the use cases I would like to implement as tests involve the user exiting the application, which results in one of the methods calling System.exit(0). This is regarded by JUnit as an error: junit.framework.AssertionFailedError: Forked Java VM exited abnormally.
Is there a way to tell JUnit that exiting with a return code of zero is actually OK?
The library System Rules has a JUnit rule called ExpectedSystemExit. With this rule you are able to test code, that calls System.exit(...):
public class MyTest {
#Rule
public final ExpectedSystemExit exit = ExpectedSystemExit.none();
#Test
public void systemExitWithArbitraryStatusCode() {
exit.expectSystemExit();
/* the code under test, which calls System.exit(...)
* with an arbitrary status
*/
}
#Test
public void systemExitWithSelectedStatusCode0() {
exit.expectSystemExitWithStatus(0);
//the code under test, which calls System.exit(0)
}
}
System Rules needs at least JUnit 4.9.
Full disclosure: I'm the author of System Rules.
How I deal with that is to install a security manager that throws an exception when System.exit is called. Then there is code that catches the exception and doesn't fail the test.
public class NoExitSecurityManager
extends java.rmi.RMISecurityManager
{
private final SecurityManager parent;
public NoExitSecurityManager(final SecurityManager manager)
{
parent = manager;
}
public void checkExit(int status)
{
throw new AttemptToExitException(status);
}
public void checkPermission(Permission perm)
{
}
}
And then in the code, something like:
catch(final Throwable ex)
{
final Throwable cause;
if(ex.getCause() == null)
{
cause = ex;
}
else
{
cause = ex.getCause();
}
if(cause instanceof AttemptToExitException)
{
status = ((AttemptToExitException)cause).getStatus();
}
else
{
throw cause;
}
}
assertEquals("System.exit must be called with the value of " + expectedStatus, expectedStatus, status);
Could you abstract out the "system exiting" into a new dependency, so that in your tests you could just have a fake which records the fact that exit has been called (and the value), but use an implementation which calls System.exit in the real application?
If anybody needs this functionality for JUnit 5, I've written an extension to do this. This is a simple annotation you can use to tell your test case to expect and exit status code or a specific exit status code.
For example, any exit code will do:
public class MyTestCases {
#Test
#ExpectSystemExit
public void thatSystemExitIsCalled() {
System.exit(1);
}
}
If we want to look for a specific code:
public class MyTestCases {
#Test
#ExpectSystemExitWithStatus(1)
public void thatSystemExitIsCalled() {
System.exit(1);
}
}

How to run tearDown type method for a specific test in JUnit class with multiple tests?

I have a junit testCase class with multiple test methods in it ( As requirement , we don't want to create separate class for each test.)
I wanna create a tearDown type method for EACH test method , which will run specifically for that test. Not for ALL test.
My problem is , in many tests i Insert record in database, test it and delete it after test.
But, If a test fails mid way , control don't reaches till end my dummy record ain't deleting.
I think only ONE tearDown() is allowed for one class, and this tearDown() don't know what object/record i created or inserted and what to delete!!!
I want to create a tearDown() or #After method just for one specific test. Something like finally{} in java for each method.
For Eg:
public class TestDummy extends TestCase {
public void testSample1(){
InsertSomeData1();
assertFalse(true);
runTearDown1();
}
public void testSample2(){
InsertSomeData2();
assertFalse(true);
runTearDown2();
}
public void runTearDown1(){
deleteDummyDatafromTestSample1....
}
public void runTearDown2(){
deleteDummyDatafromTestSample2....
}
}
Here control will never go to runTearDown1() or runTearDown2() and I don't a one common tearDown() because it won't know what data I inserted and thats specific to each method.
It seems your test relies on a fixed database, and future tests will break if your current test breaks. What I'd recommend is not to focus on this particular problem (a test-specific tearDown method that runs for each test), but your main problem - borken tests. Before your test run, it should always work with a clean database, and this should be the case for each test. Right now, your first test has a relationship with the second (through the database).
What the right approach would be is that you recreate your database before each test, or at the very least reset it to a basic state. In this case, you'll want a test like this:
public class TestDummy {
// this code runs (once) when this test class is run.
#BeforeClass
public void setupDatabase() {
// code that creates the database schema
}
// this code runs after all tests in this class are run.
#AfterClass
public void teardownDatabase() {
// code that deletes your database, leaving no trace whatsoever.
}
// This code runs before each test case. Use it to, for example, purge the
// database and fill it with default data.
#Before
public void before() {
}
// You can use this method to delete all test data inserted by a test method too.
#After
public void after() {
}
// now for the tests themselves, we should be able to assume the database will
// always be in the correct state, independent from the previous or next test cases.
#Test
public void TestSample2() {
insertSomeData();
assertTrue(someData, isValid());
}
}
Disclaimer: JUnit 4 tests (using annotations), might not be the right annotations, might not even be the right answer(s).
You could have smth like this:
interface DBTest {
void setUpDB();
void test();
void tearDownDB();
}
class DBTestRunner {
void runTest(DBTest test) throws Exception {
test.setUpDB();
try {
test.test();
} finally {
test.tearDownDB();
}
}
}
public void test48() throws Exception {
new DBTestRunner().runTest(new DBTest() {
public void setUpDB() {...}
public void test() {...}
public void tearDownDB() {...}
});
}
#iluxa . Gr8.. Your solution is perfect!!! In one test class i created two tests test48 and test49 (same as required in my code above testSample1 and testSample2) and viola! every test method now gets its own setup() and tearDown. Only this solution looks little complicated as need to use DBTestRunner in each method, but I don't see any better solution. I was thinking Junit may have some direct solution. like #After or tearDown() with some parameter or something.
Tks a lot.
Use MethodRule:
public class MyRule implements MethodRule {
#Override
public Statement apply(final Statement base, FrameworkMethod method, Object target) {
return new Statement() {
#Override
public void evaluate() throws Throwable {
try {
base.evaluate();
} catch (AssertionError e) {
doFail();
} finally {
doAnyway();
}
}
};
}
}
Then declare it in your test class:
public class TestDummy{
public MethodRule rule = new MyRule();
......
}

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