We have Eclipse UI in the frontend and have a non Java based backend.
We generally write Unit tests separately for both frontend and backend.
Also we write PDE tests which runs Eclipse UI against a dummy backend.
My question is do we need to have integration tests which test end to end.
One reason i might see these integration tests are useful are when i upgrade my frontend /backend i can run end to end tests and i find defects.
I know these kind of questions are dependent on particular scenario.
But would like to what is the general and best practice followed by all here.
cheers,
Saurav
As you say, the best approach is dependant on the application. However, in general it is a good idea to have a suite of integration tests that can test your application end-to-end, to pick up any issues that may occur when you upgrade only one layer of the application without taking those changes into account in another layer. This sounds like it would be definitely worthwhile in your case, given that you have system components written in different languages, which naturally creates more chance of issues arising due added complexity around the component interfaces.
One thing to be aware of when writing end-to-end integration tests (which some would call system tests) is that they tend to be quite fragile when compared to unit tests, which is a combination of a number of factors, including:
They require multiple components to be available for the tests, and for the communication between these components to be configured correctly.
They exercise more code than a unit test, and therefore there are more things that can go wrong that can cause them to fail.
They often involve asynchronous communication, which is more difficult to write tests for than synchronous communication.
They often require complex backend data setup before you can drive tests through the entire application.
Because of this fragility, I would advise trying to write as few tests as possible that go through the whole stack - the focus should be on covering as much functionality as possible in the fewest tests possible, with a bias towards your most important functional use-cases. A good strategy to get started would be:
Pick one key use-case (which ideally touches as many components in the application as possible), and work on getting an end-to-end test for this (even just having this single test will bring a lot of value). Focus on making this test as realistic as possible (i.e. use a production-like deployment), as reliable as possible, and as automated as possible (ideally it should run as part of continuous integration). Even just having this single test brings a lot of value.
Build out tests for other use-cases one test at a time, again focusing on your most important use-cases at first.
This approach will help to ensure that your end-to-end tests are of high quality, which is vital for their long-term health and usefulness. Too many times I have seen people try to introduce a comprehensive suite of such tests to an application, but ultimately fail because the tests are fragile & unreliable, people lose faith in them, don't run or maintain them, and eventually they forget they even had the tests in the first place.
Good luck and have fun!
Related
I'm working on an app that integrates with a 3rd party web service. I currently have separate integration / regression tests that call the web service to do the following:
Modify Policy - Add Vehicle
Modify Policy - Remove Vehicle
Modify Policy - Add Multiple Vehicles
Modify Policy - Add Insured
...
Most of these tests were created as bugs were found & fixed. The 3rd party web service is slooow and I'm trying to speed the testing process up. Because each test calls the web service, combining them into one test that only calls the web service once would make things much faster.
Would combining these tests be bad practice because each test was written for a specific bug? My concern is that a mistake in refactoring could potentially allow a bug to be re-introduced later on.
Yes, combining them would be a bad practice. Think instead about how to mitigate the risk without combining the tests. One approach - probably your best bet - would be to mock out the web service, so that the tests are much faster without jeopardizing their ability to detect a regression. Another would be to split your slow regression tests into their own suite that is run less frequently (but still frequently enough!) than your usual set of tests. Finally, you could combine them - but I would recommend explicitly reintroducing all the original bugs into your code to verify that the combined test still detects them.
Specific, pointed, direct, unit tests are very valuable; it's nice to know exactly what has broken. Combining tests compromises that value.
I wouldn't recommend combining them, unless you keep the ability to run them separately (maybe keep them separate in your overnight build, and combined in your continuous build).
Try parallelizing them (on separate 'policies'), if your test framework supports it.
I would suggest including them in your nightly build, so that they do run once a day when you are asleep and not watching the clock. And only removing them your developer time tests.
Of course that assumes they are not soooo sloooow that one night is not enough.
Just combining your tests into one big test is likely to make them useless or worse. Thats's not much better than just deleting them.
I've always worked alone and my method of testing is usually compiling very often and making sure the changes I made work well and fix them if they don't. However, I'm starting to feel that that is not enough and I'm curious about the standard kinds of tests there are.
Can someone please tell me about the basic tests, a simple example of each, and why it is used/what it tests?
Thanks.
Different people have slightly different ideas about what constitutes what kind of test, but here are a few ideas of what I happen to think each term means. Note that this is heavily biased towards server-side coding, as that's what I tend to do :)
Unit test
A unit test should only test one logical unit of code - typically one class for the whole test case, and a small number of methods within each test. Unit tests are (ideally) small and cheap to run. Interactions with dependencies are usually isolated with a test double such as a mock, fake or stub.
Integration test
An integration test will test how different components work together. External services (ones not part of the project scope) may still be faked out to give more control, but all the components within the project itself should be the real thing. An integration test may test the whole system or some subset.
System test
A system test is like an integration test but with real external services as well. If this is automated, typically the system is set up into a known state, and then the test client runs independently, making requests (or whatever) like a real client would, and observing the effects. The external services may be production ones, or ones set up in just a test environment.
Probing test
This is like a system test, but using the production services for everything. These run periodically to keep track of the health of your system.
Acceptance test
This is probably the least well-defined term - at least in my mind; it can vary significantly. It will typically be fairly high level, like a system test or an integration test. Acceptance tests may be specified by an external entity (a standard specification or a customer).
Black box or white box?
Tests can also be "black box" tests, which only ever touch the public API, or "white box" tests which take advantage of some extra knowledge to make testing easier. For example, in a white box test you may know that a particular internal method is used by all the public API methods, but is easier to test. You can test lots of corner cases by calling that method directly, and then do fewer tests with the public API. Of course, if you're designing the public API you should probably design it to be easily testable to start with - but it doesn't always work out that way. Often it's nice to be able to test one small aspect in isolation of the rest of the class.
On the other hand, black box testing is generally less brittle than white box testing: by definition, if you're only testing what the API guarantees in its contracts, then the implementation can change as much as it wants without the tests changing. White box tests, on the other hand, are sensitive to implementation changes: if the internal method changes subtly - or gains an extra parameter, for example - then you'll need to change the tests to reflect that.
It all boils down to balance, in the end - the higher the level of the test, the more likely it is to be black box. Unit tests, on the other hand, may well include an element of white box testing... at least in my experience. There are plenty of people who would refuse to use white box testing at all, only ever testing the public API. That feels more dogmatic than pragmatic to me, but I can see the benefits too.
Starting out
Now, as for where you should go next - unit testing is probably the best thing to start with. You may choose to write the tests before you've designed your class (test-driven development) or at roughly the same time, or even months afterwards (not ideal, but there's a lot of code which doesn't have tests but should). You'll find that some of your code is more amenable to testing than others... the two crucial concepts which make testing feasible (IMO) are dependency injection (coding to interfaces and providing dependencies to your class rather than letting them instantiate those dependencies themselves) and test doubles (e.g. mocking frameworks which let you test interaction, or fake implementations which do everything a simple way in memory).
I would suggest reading at least book about this, since the domain is quite huge, and books tend to synthesize better such concepts.
E.g. A very good basis might be: Software Testing Testing Across the Entire Software Development Life Cycle (2007)
I think such a book might explain better everything than some out of context examples we could post here.
Hi… I would like to add on to what Jon Skeet Sir’s answer..
Based on white box testing( or structural testing) and black box testing( or functional testing) the following are the other testing techniques under each respective category:
STRUCTURAL TESTING Techniques
Stress Testing
This is used to test bulk volumes of data on the system. More than what a system normally takes. If a system can stand these volumes, it can surely take normal values well.
E.g.
May be you can take system overflow conditions like trying to withdraw more than available in your bank balance shouldn’t work and withdrawing up to a maximum threshold should work.
Used When
This can be mainly used we your unsure about the volumes up to your system can handle.
Execution Testing
Done in order to check how proficient is a system.
E.g.
To calculate turnaround time for transactions.
Used when:
Early in the development process to see if performance criteria is met or not.
Recovery Testing
To see if a system can recover to original form after a failure.
E.g.
A very common e.g. in everyday life is the System Restore present in Windows OS..
They have restore points used for recovery as one would well know.
Used when:
When a user feels an application critical to him/her at that point of time has stopped working and should continue to work, for which he performs recovery.
Other types of testing which you could find use of include:-
Operations Testing
Compliance Testing
Security Testing
FUNCTIONAL TESTING Techniques include:
Requirements Testing
Regression Testing
Error-Handling Testing
Manual-Support Testing
Intersystem testing
Control Testing
Parallel Testing
There is a very good book titled “Effective methods for Software Testing” by William Perry of Quality Assurance Institute(QAI) which I would suggest is a must read if you want to go in depth w.r.t. Software Testing.
More on the above mentioned testing types would surely be available in this book.
There are also two other very broad categories of Testing namely
Manual Testing: This is done for user interfaces.
Automated Testing: Testing which basically involves white box testing or testing done
through Software Testing tools like Load Runner, QTP etc.
Lastly I would like to mention a particular type of testing called
Exhaustive Testing
Here you try to test for every possible condition, hence the name. This is as one would note pretty much infeasible as the number of test conditions could be infinite.
Firstly there are various tests one can perform. The Question is how does one organize it. Testing is a Vast & enjoying process.
Start Testing with
1.Smoke Testing. Once passed , go ahead with Functionality Testing. This is the Backbone of Testing. If Functionality works fine then 80% of Testing is profitable.
2.Now go with User Interface testing. AS at times User Interface is something that attracts the Client more than functionality. It is the look & feel that a client gets more attracted to it.
3.Now its time to have a look on Cosmetics bugs. Generally these bugs are ignored because of time constraint. But these play a major role depending on the page it is found. A spelling mistake turns to be Major when found on Splash Screen Or Your landing page or the App name itself. Hence these can not be overlooked as well.
4.Do Conduct Compatibility Testing. i,e Testing on Various Browsers & browser Versions. May be devices & OS for Responsive applications.
Happy testing :)
I am writing an application that uses 3rd party libraries to instantiate and make some operations on virtualmachines.
At first I was writing integration tests to every functionality of the application. But them I found that these tests were not really helping since my environment had to be at a determined state, which turned the tests more and more difficult to write. And I decided to make only the unit and acceptance tests.
So, my question ... is/can there be method or a clue to notice when the integration tests are not to be used?? (or I am wrong and on all cases they should be written)
When you don't plan on actually hooking your application up to anything "real"; no real containers, databases, resources or actual services. That's what an integration test is supposed to verify; that everything works properly together.
Integration tests are good to test a full system that has well-defined inputs and outputs that are unlikely to change. If your expected input/outputs change often then maintaining the test may become a maintenance challenge, or, worse, you may choose against improving an interface because of the amount of work that may be required to upgrade the integration tests.
The easy and short rule is: Test in integration test what breaks due to integration and test the rest in unit tests in isolation.
You can even hate integration tests. Writing a unit test for a function that takes only one integer parameter is hard enough. All possible combinations of state (internal and external(time, external systems)) and input can make integration testing practically impossible (for a decent application.)
Each release it seems that our customers find a few old issues with our software. It makes it look like every release has multiple bugs, when in reality our new code is generally solid.
We have tried to implement some additional testing where we have testers do several hours of monthly regression testing on a single app each month in an effort to stay ahead of small issues. We refer to this process as our Software Hardening process, but it does not seem like we are catching enough of the bugs and it feels like a very backburner process since there is always new code to write.
Is there a trick to this kind of testing? Do I need to target one specific feature at a time?
When you develop your testing procedures, you may want to implement these kind of tests:
unit testing (testing invididual components of your project to test their functionality), these tests are important because they allow you to pinpoint where in the software the error may come from. Basically in these tests you will test a single functionality and use mock objects to simulate the behavior, return value of other objects/entities.
regression testing, which you mentioned
characterization testing, one example could be running automatically the program on automatically generated input (simulating the user input), storing the results and compare the results of every version against these results.
At the beginning this will be very heavy to put in place, but with more releases and more bugs fixes being added to the automated non-regression tests, you should be starting to save time.
It is very important that you do not fall in the trap of designing huge numbers of dumb tests. Testing should make your life easier, if you spend too much time understanding where the tests have broken you should redesign the tests such as they give you better messages/understanding of the problem so you can locate the issue quickly.
Depending of your environment, these tests can be linked to the development process.
In my environment, we use SVN for versioning, a bot runs the tests against every revision and returns the failing tests and messages with the name of the revision which broke it and the contributor (his login).
EDIT:
In my environment, we use a combination of C++ and C# to deliver analytics used in Finance, the code was C++ and is quite old while we are trying to migrate the interfaces toward C# and keep the core of the analytics in C++ (mainly because of speed requirements)
Most of the C++ tests are hand-written unit tests and regression tests.
On the C# side we are using NUnit for unit testing. We have a couple of general tests.
We have a 0 warnings policy, we explicitely forbid people to commit code which is generating warnings unless they can justify why it is useful to bypass the warning for this part of the code. We have as well conventions about exception safety, the use of design patterns and many other aspects.
Setting explicitely conventions and best practices is another way to improve the quality of your code.
Is there a trick to this kind of testing?
You said, "we have testers do several hours of monthly regression testing on a single app each month in an effort to stay ahead of small issues."
I guess that by "regression testing" you mean "manually exercising old features".
You ought to decide whether you're looking for old bugs which have never been found before (which means, running tests which you've never run before); or, whether you're repeating previously-run tests to verify that previously-tested functionality is unchanged. These are two opposite things.
"Regression testing" implies to me that you're doing the latter.
If the problem is that "customers find a few old issues with our software" then either your customers are running tests which you've never run before (in which case, to find these problems you need to run new tests of old software), or they're finding bugs which you have previous tested and found, but which you apparently never fixed after you found them.
Do I need to target one specific feature at a time?
What are you trying to do, exactly:
Find bugs before customers find them?
Convince customers that there's little wrong with the new development?
Spend as little time as possible on testing?
Very general advice is that bugs live in families: so when you find a bug, look for its parents and siblings and cousins, for example:
You might have this exact same bug in other modules
This module might be buggier than other modules (written by somone on an off day, perhaps), so look for every other kind of bug in this module
Perhaps this is one of a class of problems (performance problems, or low-memory problems) which suggests a whole area (or whole type of requirement) which needs better test coverage
Other advice is that it's to do with managing customer expectations: you said, "It makes it look like every release has multiple bugs, when in reality our new code is generally solid" as if the real problem is the mistaken perception that the bug is newly-written.
it feels like a very backburner process since there is always new code to write
Software develoment doesn't happen in the background, on a burner: either someone is working on it, or they're not. Management must to decide whether to assign anyone to this task (i.e. look for existing previously-unfound bugs, or fix-previously-found-but-not-yet-reported bugs), or whether they prefer to concentrate on new development and let the customers do the bug-detecting.
Edit: It's worth mentioning that testing isn't the only way to find bugs. There's also:
Informal design reviews (35%)
Formal design inspections (55%)
Informal code reviews (25%)
Formal code inspections (60%)
Personal desk checking of code (40%)
Unit test (30%)
Component test (30%)
Integration test (35%)
Regression test (25%)
System test (40%)
Low volume beta test (<10 sites) (35%)
High-volume beta test (>1000 sites) (70%)
The percentage which I put next to each is a measure of the defect-removal rate for each technique (taken from page 243 of McConnel's Software Estimation book). The two most effective techniques seem to be formal code inspection, and high-volume beta tests.
So it might be a good idea to introduce formal code reviews: that might be better at detecting defects than black-box testing is.
As soon as your coding ends, first you should go for the unit testing. THere you will get some bugs which should be fixed and you should perform another round of unit testing to find if new bugs came or not. After you finish Unit testing you should go for functional testing.
YOu mentioned here that your tester are performing regression testing on a monthly basis and still there are old bugs coming out. So it is better to sit with the tester and review the test cases as i feel that they need to be updated regularly. Also during review put stress on which module or functionality the bugs are coming. Stress on those areas and add more test cases in those areas and add those in your rgression test cases so that once new build comes those test cases should be run.
YOu can try one more thing if your project is a long term one then you should talk with the tester to automate the regression test cases. It will help you to run the test cases at off time like night and in the next day you will get the results. Also the regression test cases should be updated as the major problem comes when regression test cases are not updated regularly and by running old regression test cases and new progression test cases you are missing few modules that are not tested.
There is a lot of talk here about unit testing and I couldn't agree more. I hope that Josh understands that unit testing is a mechanized process. I disagree with PJ in that unit tests should be written before coding the app and not after. This is called TDD or Test Driven Development.
Some people write unit tests that exercise the middle tier code but neglect testing the GUI code. That is imprudent. You should write unit tests for all tiers in your application.
Since unit tests are also code, there is the question of QA for your test suite. Is the code coverage good? Are there false positives/negatives errors in the unit tests? Are you testing for the right things? How do you assure the quality of your quality assurance process? Basically, the answer to that comes down to peer review and cultural values. Everyone on the team has to be committed to good testing hygiene.
The earlier a bug is introduced into your system, the longer it stays in the system, the harder and more costly it is to remove it. That is why you should look into what is known as continuous integration. When set up correctly, continuous integration means that the project gets compiled and run with the full suite of unit tests shortly after you check in your changes for the day.
If the build or unit tests fail, then the offending coder and the build master gets a notification. They work with the team lead to determine what the most appropriate course correction should be. Sometimes it is just as simple as fix the problem and check the fix in. A build master and team lead needs to get involved to identify any overarching patterns that require additional intervention. For example, a family crisis can cause a developer's coding quality to bottom out. Without CI and some managerial oversight, it might take six months of bugs before you realize what is going on and take corrective action.
You didn't mention what your development environment is. If yours were a J2EE shop, then I would suggest that you look into the following.
CruiseControl for continuous integration
Subversion for the source code versioning control because it integrates well with CruiseControl
Spring because DI makes it easier to mechanize the unit testing for continuous integration purposes
JUnit for unit testing the middle tier
HttpUnit for unit testing the GUI
Apache JMeter for stress testing
Going back and implementing a testing strategy for (all) existing stuff is a pain. It's long, it's difficult, and no one will want to do it. However, I strongly recommend that as a new bug comes in, a test be developed around that bug. If you don't get a bug report on it, then either is (a) works or (b) the user doesn't care that it doesn't work. Either way, a test is a waste of your time.
As soon as its identified, write a test that goes red. Right now. Then fix the bug. Confirm that it is fixed. Confirm that the test is now green. Repeat as new bugs come in.
Sorry to say that but maybe you're just not testing enough, or too late, or both.
Recently I've came up with the question is it worth at all to spent development time to generate automatic unit test for web based projects? I mean it seems useless at some point because at some point those projects are oriented on interactions with users/clients, so you cannot anticipate the whole possible set of user action so you be able to check the correctness of content showed. Even regression test can hardly be done. So I'm very eager to know to know the opinion of other experienced developers.
Selenium have a good web testing framework
http://seleniumhq.org/
Telerik are also in the process of developing one for web app testing.
http://www.telerik.com/products/web-ui-test-studio.aspx
You cannot anticipate the whole
possible set of user action so you be
able to check the correctness of
content showed.
You can't anticipate all the possible data your code is going to be handed, or all the possible race conditions if it's threaded, and yet you still bother unit testing. Why? Because you can narrow it down a hell of a lot. You can anticipate the sorts of pathological things that will happen. You just have to think about it a bit and get some experience.
User interaction is no different. There are certain things users are going to try and do, pathological or not, and you can anticipate them. Users are just inputting particularly imaginative data. You'll find programmers tend to miss the same sorts of conditions over and over again. I keep a checklist. For example: pump Unicode into everything; put the start date after the end date; enter gibberish data; put tags in everything; leave off the trailing newline; try to enter the same data twice; submit a form, go back and submit it again; take a text file, call it foo.jpg and try to upload it as a picture. You can even write a program to flip switches and push buttons at random, a bad monkey, that'll find all sorts of fun bugs.
Its often as simple as sitting someone down who's unfamiliar with the software and watching them use it. Fight the urge to correct them, just watch them flounder. Its very educational. Steve Krug refers to this as "Advanced Common Sense" and has an excellent book called "Don't Make Me Think" which covers cheap, simple user interaction testing. I highly recommend it. It's a very short and eye opening read.
Finally, the client themselves, if their expectations are properly prepared, can be a fantastic test suite. Be sure they understand its a work in progress, that it will have bugs, that they're helping to make their product better, and that it absolutely should not be used for production data, and let them tinker with the pre-release versions of your product. They'll do all sorts of things you never thought of! They'll be the best and most realistic testing you ever had, FOR FREE! Give them a very simple way to report bugs, preferably just a one button box right on the application which automatically submits their environment and history; the feedback box on Hiveminder is an excellent example. Respond to their bugs quickly and politely (even if its just "thanks for the info") and you'll find they'll be delighted you're so responsive to their needs!
Yes, it is. I just ran into an issue this week with a web site I am working on. I just recently switched-out the data access layer and set up unit tests for my controllers and repositories, but not the UI interactions.
I got bit by a pretty obvious bug that would have been easily caught if I had integration tests. Only through integration tests and UI functionality tests do you find issues with the way different tiers of the application interact with one another.
It really depends on the structure and architecture of your web application. If it contains an application logic layer, then that layer should be easy to unit test with automating tools such as Visual Studio. Also, using a framework that has been designed to enable unit testing, such as ASP.NET MVC, helps alot.
If you're writing a lot of Javascript, there have been a lot of JS testing frameworks that have come around the block recently for unit testing your Javascript.
Other than that, testing the web tier using something like Canoo, HtmlUnit, Selenium, etc. is more a functional or integration test than a unit test. These can be hard to maintain if you have the UI change a lot, but they can really come in handy. Recording Selenium tests is easy and something you could probably get other people (testers) to help you create and maintain. Just know that there is a cost associated with maintaining tests, and it needs to be balanced out.
There are other types of testing that are great for the web tier - fuzz testing especially, but a lot of the good options are commercial tools. One that is open source and plugs into Rails is called Tarantula. Having something like that at the web tier is a nice to have run in a continuous integration process and doesn't require much in the form of maintenance.
Unit tests make sense in TDD process. They do not have much value if you don't do test-first development. However the acceptance test are a big thing for quality of the software. I'd say that acceptance test is a holy grail of the development. Acceptance tests show whether the application satisfies the requirements. How do I know when to stop developing the feature --- only when all my acceptance test pass. Automation of acceptance testing a big thing because I do not have to do it all manualy each time I make changes to the application. After months of development there can be hundreds of test and it becomes unfeasible (sometime impossible) to run all the test manually. Then how do I know if my application still works?
Automation of acceptance tests can be implemented with use of xUnit test frameworks, which makes a confusion here. If I create an acceptance test using phpUnit or httpUnit is it a unit test? My answer is no. It does not matter what tool I use to create and run test. Acceptance test is the one that show whether the features is working IAW requirements. Unit test show whether a class (or function) satisfies the developer's implementation idea. Unit test has no value for the client (user). Acceptance test has a lot of value to the client (and thus to developer, remember Customer Affinity)
So I strongly recommend creating automated acceptance tests for the web application.
The good frameworks for the acceptance test are:
Sahi (sahi.co.in)
Silenium
Simpletest (I't a unit-test framework for php, but includes the browser object that can be used for acceptance testing).
However
You have mentioned that web-site is all about user interaction and thus test automation will not solve the whole problem of usability. For example: testing framework shows that all tests pass, however the user cannot see the form or link or other page element due to accidental style="display:none" in the div. The automated tests pass because the div is present in the document and test framework can "see" it. But the user cannot. And the manual test would fail.
Thus, all web-applications needs manual testing. The automated test can reduce the test workload drastically (80%), but manual test are as well significant for the quality of the resulting software.
As for the Unit testing and TDD -- it make the code quality. It is beneficial to the developers and for the future of the project (i.e. for projects longer that a couple of month). However TDD requires skill. If you have the skill -- use it. If you don't consider gaining the skill, but mind the time it will take to gain. It usually takes about 3 - 6 month to start creating a good Unit tests and code. If you project will last more that a year, I recommend studding TDD and investing time in proper development environment.
I've created a web test solution (docker + cucumber); it's very basic and simple, so easy to understand and modify / improve. It lies in the web directory;
my solution: https://github.com/gyulaweber/hosting_tests