are pytest_sessionstart(session) and pytest_sessionfinish(session) valid hooks? They are not described in dev hook docs or latest hook docs
What is the difference between them and pytest_configure(config)/pytest_unconfigure(config)?
In docs it is said:
pytest_configure(config)called after command line options have been parsed. and all plugins
and initial conftest files been loaded.
and
pytest_unconfigure(config) called before test process is exited.
Session is the same, right?
Thanks!
The bad news is that the situation with sessionstart/configure is not very well specified. Sessionstart in particular is not much documented because the semantics differ if one is in the xdist/distribution case or not. One can distinguish these situations but it's all a bit too complicated.
The good news is that pytest-2.3 should make things easier. If you define a #fixture with scope="session" you can implement a fixture that is called once per process within which test execute.
For distributed testing, this means once per test slave. For single-process testing, it means once for the whole test run. In either case, if you do a "--collectonly" run, or "-h" or other options that do not involve the running of tests, then fixture functions will not execute at all.
Hope this clarifies.
Related
Well the system we have has a bunch of dependencies, but I'll try to summarize what's going on without divulging too much details.
Test assembly in the form of a .dll is the one being executed. A lot of these tests call an API.
In the problematic method, there's 2 API calls that have an await on them: one to write a record to that external interface, and another to extract all records and then read the last one in that external interface, both via API. The test is simply to check if writing the last record was successful in an end-to-end context, that's why there's both a write and then a read.
If we execute the test in Visual Studio, everything works as expected. I also tested it manually via command lining vstest.console.exe, and the expected results always come out as well.
However, when it comes to VS Test task in VSTS, it fails for some reason. We've been trying to figure it out, and eventually we reached the point where we printed the list from the 'read' part. It turns out the last record we inserted isn't in the data we pulled, but if we check the external interface via a different method, we confirmed that the write process actually happened. What gives? Why is VSTest getting like an outdated set of records?
We also noticed two things:
1.) For the tests that passed, none of the Console.WriteLine outputs appear in the logs. Only on Failed test do they do so.
2.) Even if our Data.Should.Be call is at the very end of the TestMethod, the logs report the fail BEFORE it prints out the lines! And even then, the printing should happen after reading the list of records, and yet when the prints do happen we're still missing the record we just wrote.
Is there like a bottom-to-top thing we're missing here? It really seems to me like VSTS vstest is executing the assert before the actual code. The order of TestMethods happen the right order though (the 4th test written top-to-bottom in the code is executed 4th rather than 4th to last) and we need them to happen in the right order because some of the later tests depend on the former tests succeeding.
Anything we're missing here? I'd put a source code but there's a bunch of things I need to scrub first if so.
Turns out we were sorely misunderstanding what 'await' does. We're using .Wait() instead for the culprit and will also go back through the other tests to check for quality.
I'm trying to automate a lengthy process that can be broken down into several steps. (say Steps 1-5)
I have written a script that separates these into functions and call them sequentially.
However, we now have the additional requirement of making the script restartable. That is, if it fails in any one of the steps, rerunning the script would cause it to skip all completed steps and retry from the failed one.
Is this at all possible without referencing an external log file?
I've tried using workflows but it seems like recursion isn't supported.
Any ideas?
Some options aside from using a log file.
Use the registry
you can set a registry value to a number depending on what step you stopped on, this removes the need for a log file but is somewhat similar in terms of 'external' storage
Check the task status on each run
depending on the tasks you could have the script 'test', for example, step 3 to see if it has already been completed, then check step 4, 5 etc. until it encounters one it needs to run and continue from there, this may be impossible or require a lot of overhead code though for not much payoff.
Allow the user to continue from within the script.
this is probably the best way of doing it (aside from just using a log file), run the script in blocks, and when an error is encountered you can prompt the user to fix the issue before pressing 'enter' to re-run the previous script block, this makes it easy to provide information about what failed as well.
the main thing here is that once a script 'quits', in order to know what happened in it's last run it needs an external source of information, or to handle it in another way.
I have a general question about how to debug in Simpy. Normal debugging tools don't seem to work, since everything is working on the event loop, and you can't step through the code line by line and inspect what exists at any point in time.
Primarily, I'm interested in finding what kinds of processes and callbacks are in existence at a particular time, and how to remove them at the appropriate point. Are there any best practices surrounding debugging in discrete event simulation generally?
I would just use a bunch of print()s.
One thing you might find useful is the specific requests that can be passed to primitives such as resources. For example you can ask a resource how many users it currently has or how big the queue to use the resource is with:
All of these commands can be found in the documentation, here is the resource example: https://simpy.readthedocs.io/en/latest/api_reference/simpy.resources.html
I have a complex set of integration tests that uses Perl's WWW::Mechanize to drive a web app and check the results based on specific combinations of data. There are over 20 subroutines that make up the logic of the tests, loop through data, etc. Each test runs several of the test subroutines on a different dataset.
The web app is not perfect, so sometimes bugs cause the tests to fail with very specific combinations of data. But these combinations are rare enough that our team will not bother to fix the bugs for a long time; building many other new features takes priority.
So what should I do with the failing tests? It's just a few tests out of several dozen per combination of data.
1) I can't let it fail because then the whole test suite would fail.
2) If we comment them out, that means we miss out on making that test for all the other datasets.
3) I could add a flag in the specific dataset that fails, and have the test not run if that flag is set, but then I'm passing extra flags all over the place in my test subroutines.
What's the cleanest and easiest way to do this?
Or are clean and easy mutually exclusive?
That's what TODO is for.
With a todo block, the tests inside are expected to fail. Test::More will run the tests normally, but print out special flags indicating they are "todo". Test::Harness will interpret failures as being ok. Should anything succeed, it will report it as an unexpected success. You then know the thing you had todo is done and can remove the TODO flag.
The nice part about todo tests, as opposed to simply commenting out a block of tests, is it's like having a programmatic todo list. You know how much work is left to be done, you're aware of what bugs there are, and you'll know immediately when they're fixed.
Once a todo test starts succeeding, simply move it outside the block. When the block is empty, delete it.
I see two major options
disable the test (commenting it out), with a reference to your bugtracking system (i.e. a bug ig), possibly keeping a note in the bug as well that there is a test ready for this bug
move the failing tests in a seperate test suite. You could even reverse the failing assertion so you can run the suite and while it is green the bug is still there and if it becomes red either the bug is gone or something else is fishy. Of course a link to the bugtracking system and bag is still a good thing to have.
If you actually use Test::More in conjunction with WWW::Mechanize, case closed (see comment from #daxim). If not, think of a similar approach:
# In your testing module
our $TODO;
# ...
if (defined $TODO) {
# only print warnings
};
# in a test script
local $My::Test::TODO = "This bug is delayed until iteration 42";
Am I a bad person if I use use Test::More qw(no_plan)?
The Test::More POD says
Before anything else, you need a testing plan. This basically declares how many tests your script is going to run to protect against premature failure...
use Test::More tests => 23;
There are rare cases when you will not know beforehand how many tests your script is going to run. In this case, you can declare that you have no plan. (Try to avoid using this as it weakens your test.)
use Test::More qw(no_plan);
But premature failure can be easily seen when there are no results printed at the end of a test run. It just doesn't seem that helpful.
So I have 3 questions:
What is the reasoning behind requiring a test plan by default?
Has anyone found this a useful and time saving feature in the long run?
Do other test suites for other languages support this kind of thing?
What is the reason for requiring a test plan by default?
ysth's answer links to a great discussion of this issue which includes comments by Michael Schwern and Ovid who are the Test::More and Test::Most maintainers respectively. Apparently this comes up every once in a while on the perl-qa list and is a bit of a contentious issue. Here are the highlights:
Reasons to not use a test plan
Its annoying and takes time.
Its not worth the time because test scripts won't die without the test harness noticing except in some rare cases.
Test::More can count tests as they happen
If you use a test plan and need to skip tests, then you have the additional pain of needing a SKIP{} block.
Reasons to use a test plan
It only takes a few seconds to do. If it takes longer, your test logic is too complex.
If there is an exit(0) in the code somewhere, your test will complete successfully without running the remaining test cases. An observant human may notice the screen output doesn't look right, but in an automated test suite it could go unnoticed.
A developer might accidentally write test logic so that some tests never run.
You can't really have a progress bar without knowing ahead of time how many tests will be run. This is difficult to do through introspection alone.
The alternative
Test::Simple, Test::More, and Test::Most have a done_testing() method which should be called at the end of the test script. This is the approach I take currently.
This fixes the problem where code has an exit(0) in it. It doesn't fix the problem of logic which unintentionally skips tests though.
In short, its safer to use a plan, but the chances of this actually saving the day are low unless your test suites are complicated (and they should not be complicated).
So using done_testing() is a middle ground. Its probably not a huge deal whatever your preference.
Has this feature been useful to anyone in the real world?
A few people mention that this feature has been useful to them in the real word. This includes Larry Wall. Michael Schwern says the feature originates with Larry, more than 20 years ago.
Do other languages have this feature?
None of the xUnit type testing suites has the test plan feature. I haven't come across any examples of this feature being used in any other programming language.
I'm not sure what you are really asking because the documentation extract seems to answer it. I want to know if all my tests ran. However, I don't find that useful until the test suite stabilizes.
While developing, I use no_plan because I'm constantly adding to the test suite. As things stabilize, I verify the number of tests that should run and update the plan. Some people mention the "test harness" catching that already, but there is no such thing as "the test harness". There's the one that most modules use by default because that's what MakeMaker or Module::Build specify, but the TAP output is independent of any particular TAP consumer.
A couple of people have mentioned situations where the number of tests might vary. I figure out the tests however I need to compute the number then use that in the plan. It also helps to have small test files that target very specific functionality so the number of tests is low.
use vars qw( $tests );
BEGIN {
$tests = ...; # figure it out
use Test::More tests => $tests;
}
You can also separate the count from the loading:
use Test::More;
plan tests => $tests;
The latest TAP lets you put the plan at the end too.
In one comment, you seem to think prematurely exiting will count as a failure, since the plan won't be output at the end, but this isn't the case - the plan will be output unless
you terminate with POSIX::_exit or a fatal signal or the like. In particular, die() and exit() will result
in the plan being output (though the test harness should detect anything other than an exit(0) as a prematurely terminated test).
You may want to look at Test::Most's deferred plan option, soon to be in Test::More (if it's not already).
There's also been discussion of this on the perl-qa list recently. One thread: http://www.nntp.perl.org/group/perl.qa/2009/03/msg12121.html
Doing any testing is better than doing no testing, but testing is about being deliberate. Stating the number tests expected gives you the ability to see if there is a bug in the test script that is preventing a test from executing (or executing too many times). If you don't run tests under specific conditions you can use the skip function to declare this:
SKIP: {
skip $why, $how_many if $condition;
...normal testing code goes here...
}
I think it's ok to bend the rules and use no_plan when the human cost of figuring out the plan is too high, but this cost is a good indication that the test suite has not been well designed.
Another case where it's useful to have the test_plan explicitely defined is when you are doing this kind of tests:
$coderef = sub { my $arg = shift; isa_ok $arg, 'MyClass' };
do(#args, $coderef);
and
## hijack our interface to test it's called.
local *MyClass::do = $coderef;
If you don't specify a plan, it's easy to miss out that your test failed and that some assertions weren't run as you expected.
Having explicitly the number of test in the plan is a good idea, unless it is too expensive to retrieve this number. The question has been properly answered already but I wanted to stress two points:
Better than no_plan is to use done_testing()
use Test::More;
... run your tests ...;
done_testing( $number_of_tests_run );
# or done_testing() if not number of test is known
this Matt Trout blog entry is interesting, and rants about adding a plan vs cvs conflicts and other issues that make the plan problematic: Why numeric test plans are bad, wrong, and don't actually help anyway
I find it annoying, too, and I usually ignore the number at the very beginning until the test suite stabilizes. Then I just keep it up to date manually. I do like the idea of knowing how many total tests there are as the seconds tick by, as a kind of a progress indicator.
To make counting easier I put the following before each test:
#----- load non-existant record -----
....
#----- add a new record -----
....
#----- load the new record (by name) -----
....
#----- verify the name -----
etc.
Then I can quickly scan the file and easily count the tests, just looking for the #----- lines. I suppose I could even write something up in Emacs to do it for me, but it's honestly not that much of a chore.
It is a pain when doing TDD, because you are writing new tests opportunistically. When I was teaching TDD and the shop used Perl, we decided to use our test suite the no plan way. I guess we could have changed from no_plan to lock down the number of tests. At the time I saw it as more hindrance than help.
Eric Johnson's answer is exactly correct. I just wanted to add that done_testing, a much better replacement to no_plan, was released in Test-Simple 0.87_1 recently. It's an experimental release, but you can download it directly from the previous link.
done_testing allows you to declare the number of tests you think you've run at the end of your testing script, rather than trying to guess it before your script starts. You can read the documentation here.