I asked this auestion on NUnit-Discuss, but i realize that group is not very active, so i give it a try here:
We've been using MSTests until now for some functional tests.
I know, neither MSTest nor NUnit is really for functional test, but we need those tests with a simple integration in Visual Studio.
The tests will launch other executables, connect, do stuff, disconnect and kill the processes.
We're having trouble with MSTest in that it launched tests in a separate thread and seems that some execution is overlapping between tests, even when executed sequentially.
So i'm thinking about moving to NUnit.
The question i have is:
Can NUnit be configured in any way such as to give the following guarantees:
Tests will be executed sequentially, in an order that can be specified.
Tests will be executed from the same thread.
TearDown code of one test will have been fully executed before Setup code of a following test will be called.
If so, what would be that configuration, if any particular?
Thank you.
By default, NUnit does not execute any tests in parallel. If you never use the ParallelizableAttribute, then your tests run one at a time.
Of course, that does not mean your tests can't break NUnit, for example, by starting a thread or process that never terminates after the test thread terminates. NUnit only takes responsibility for the tests it runs itself.
NUnit does not guarantee that all tests will be executed from the same thread. That is a separate matter from parallelization, of course. Separate threads may be started for each thread, based on attributes you specify. You may, for example, designate some tests to run in a Single-threaded Apartment, while others run by default in an MTA. You might use the RequiresThreadAttribute, which asks NUnit to use a new thread for the test it decorates. You might use the SingleThreadedAttribute on a class, to indicate that all the code in that class runs on the same thread.
One trick, which is currently available but which may not exist in all future releases, is to specify --workers=0 on the command-line to nunit3-console. That tells NUnit to simply run the tests without creating any test workers and gives an execution path that more closely resembles that of NUnit V2.
So, in general, I think your needs can be met, but it could require some tinkering with your tests to make it work the way you want.
Related
Im writing automation tests for our website using NUnit and Selenium.
We have 2 different users (aminInt and hsuInt) and 3 features which need to be tested (in the example below TestA, TestB, TestC)
In my example below, there are in total 6 automation tests in the test explorer as each feature is being tested with both users.
Everything works. Each test is getting its own webDriver and all the tests are independent.
Now i want to start the tests in parallel.
I already tried everything i could find online. Tried the different parameter in parallelizable, but i cant get it right.
I would like to start 2 test at a time.
For example:
First test:
TestA adminInt
TestA hsuInt
after both tests above are done, it should start:
Second Test:
TestB adminInt
TestB hsuInt
If your goal is to save time and your tests are truly independent, then trying to control the order of execution isn't what you want. Essentially, it's NUnit's job to figure out how to run in parallel. Your job is merely to tell NUnit whether the tests you wrote are capable of running in parallel.
To tell NUnit which tests may be run in parallel, use the [Non]ParallelizableAttribute. If you place attributes on the fixtures, their different meaning is as follows...
[NonParallelizable] means that the fixture is not capable of running in parallel with any other fixtures. That's the default if you don't specify any attribute.
[Parallelizable] means that the fixture is capable of running in parallel with other fixtures in your test.
[Parallelizable(ParallelScope.All)] means that both the fixture and all the individual tests under that fixture are capable of running in parallel.
[Parallelizable(ParallelScope.Children] means that the fixture is not capable of running in parallel with other fixtures but the test methods under it may run in parallel with one another.
I stressed capable above because that's what you should focus on. Don't use the attribute with the expectation that NUnit will run some tests together with other specific tests because there is no NUnit feature to do that. Keep your focus on what you can control... writing independent, parallelizable tests and telling NUnit which ones they are.
If you find that NUnit starts too many test threads at one time, you can place a LevelOfParallelism attribute in your AssemblyInfo.cs. However, keep in mind that NUnit defaults depending on the number of cores available. So what works for you on your development machine may not give the best performance in your CI builds. My advice is to let NUnit use its defaults for most things until you see a reason to override them.
Thanks for the answers.
I found a solution for how to start just 2 tests in parallel.
With this parameter in front of the class, only 2 tests will start in parallel.
//[assembly: LevelOfParallelism(2)] You need this parameter only inside of one class. So if you have different classes which have their own tests, add this parameter to only one class and it will run all tests in parallel as long as you have the fixture command too.
[TestFixture("userA")]
[TestFixture("userB")]
To start the test for 2 different users for example.
could someone explain please how Flutter/Dart tests are executed using test runner?
Are the tests executed synchronously or asynchronously?
Does the testing framework execute every single test synchronously, meaning that only a single test and test suite is executed at any single time?
Or does the testing framework only execute a single test at a time within a test suite, but are able to execute multiple test suites at the same time?
Or testing framework run all tests and test suites completely independent of each other at the same time, completely asynchronously?
This is important because it has a direct impact on the way we are or aren't able to structure our tests, especially when it comes to the set up and tear downs of tests, and the way we assert functionality is working correctly.
Thanks!
In general, dart test will execute many tests in parallel (the parallelism level varies based on CPU core count), but you can disable this with a command line flag.
You should not write tests with any inter-dependence (i.e. one test should not rely on some global state set up by another test). For example, you may find that because your laptop has a different CPU configuration to your CI server, your tests might pass locally but fail in CI due to different ordering.
If you have some setup logic that is very expensive, and needs to be reused between multiple tests, you can use setUpAll() to run some code once before every test in a test group, however this is still discouraged. Personally, I prefer to just join the tests into one long test, to keep all tests self-contained.
This has some advantages. For example, you can use --total-shards and --shard-index to parallelize tests in CI (by creating multiple jobs to each run a different subset of the test suite).
You can also randomize the order of your tests with --test-randomize-ordering-seed, to make sure you aren't accidentally setting up such dependences between tests that might invalidate their results (i.e. perhaps test2 only passes if it happens after test1, randomizing the ordering will catch this).
TLDR
Many tests run in parallel. Try to keep tests self-contained, with no dependence on the order of tests. Extract setup logic into functions and pass it into setUp. If you really really need the performance, you can try setUpAll but avoid it if possible.
I'm running JUnit 4 with AnyLogic. In one of my tests, I need access to the Experiment running the test. Is there any clean way to access it at runtime? E.g., is there a static method along the lines of Experiment.getRunningExperiment()?
There isn't a static method that I know of (and, if there was, it might be complicated by multi-run experiments which permit parallel execution, although perhaps not since there's still a single Experiment, though there'd be thread-safety issues).
However, you can use getEngine().getExperiment() from within a model. You probably need to explain more about your usage context. If you're using AnyLogic Pro and exporting the model to run standalone, then you should have access to the experiment instance anyway (as in the help "Running the model from outside without UI").
Are you trying to run JUnit tests from within an Experiment? If so, what's your general design? Obviously JUnit doesn't sit as well in that scenario since it 'expects' to be instantiating and running the thing to be tested. For my automated tests (where I can't export it standalone because I don't use AnyLogic Pro), I judged that it was easier to avoid JUnit (it's just a framework after all) and implement the tests 'directly' (by having my model components write outputs and, at the end of the run in the Experiment, having the Experiment compare the outputs to pre-prepared expected ones and flag if the test was passed or failed). With AnyLogic Pro, you could still export standalone and use JUnit to run the 'already-a-test' Experiments (with the JUnit test checking the Experiment for a testPassed Boolean being set at the end or whatever).
The fact that you want to get running experiments suggests that you're potentially doing this whilst runs are potentially executing. If so, could you explain a bit about your requirements?
I have a test suite of ~ 1500 tests and they generally run and finish within 'reasonable time'.
Recently, however, I've changed parts of the code to use threads -- and now my builds fail from time to time by simply timing out. I imagine that a thread refuses to die and the build waits until reaching the maximum build time.
My problem is how to detect which test is causing the problem?
Can I activate some logging that shows me that a test has started/finished? I can of course be done by inserting code in every single test method - or just the fixtures, but that is A LOT of work that I'd rather avoid.
I'd suggest upgrading to NUnit 2.5 and decorating your tests with Timeout attribute, specifying maximum per-test run time. For example, you can put this in your AssemblyInfo.cs:
[assembly: NUnit.Framework.Timeout(100)]
NUnit will now launch each test in a separate thread and cancell it if it exceeds its time slot. However, this might be costly, so it's probably better to identify long-running tests and then remove assembly-level attribute in favor of test-fixture time slots. You can also override this on individual tests, assigning them more time to run.
This way you move the timeout/hang detection from CruiseControl.Net to NUnit and get information inside the report on the tasks that did not complete properly. Unfortunately there's no way for CC.Net to get this information when it has to kill the process because of timeout.
This might seem a sily question to those who are well versed in autonmation but I am struggling with many things. Here's one:
I am finding that the tests I created with Selenium RC in Visual Studio 2008 are getting run from NUnit in the alphabetical order of their names?
What am I missing? Is there a way to organize the order in which the tests in Nunit are run?
Thanks!
Technically, your unit tests should all be able to run independently of each other so ordering should not matter.
I think it might be time to re-think how you are doing your tests.
If you just want them run in a specific order because that's how you "prefer" them to be run, then I would argue that you are throwing away precious time doing something that really isn't that important.
If you need specific things done before the tests are executed, check out the setup and teardown methods.