I need to write unit tests for an existing Java REST server.
The GET methods are very similar and I am thinking that I can write a small unit test generator that will use reflection to introspect the GET methods and the POJOs they consume to generate (boilerplate) unit tests.
Each test will be generated with a small syntax error so that they cannot be run as is, but must be examined by a developer and the syntax error corrected. I am hoping that this will as least assure that the tests are sane and look reasonable.
The generator will be run from the command line, passing in the class-under-test, the output directory for the unit tests, etc.
I don't want the class files for the generator to be added to the WAR file, but the generator needs to have access to the class files for the REST server.
My project directory is a "standard" Maven hierarchy: project/src/main/java, project/target, etc.
Where is the best place to put the generator source code? Under project/src/main/java? Under project/src/generator/java? Somewhere else?
I know how to exclude the generated class files from the WAR file if they all are included under a specific package (e.g. com.example.unit_test_generator).
This scenario sound like a maven-plugin to me. Furthermore the usual place for generated code is under target/generated... which means target folder ...take a look at maven-antlr3-plugin or maven-jaxb-plugin to see where they usually put generated code into. Never put generated code into src/ structure...But may be you have to change the location and to put into project/src/main/ ...But if these classes are some kind of tests the have to be located under project/src/test instead.
Related
I have a javacc file which I'm trying to write unit tests for. Is it more effective to make unit tests for the .jj file or for the java files the jj file produces when it is compiled. I know this was asked here, but a lot of the links on the answer are dead. Any help, tips are appreciated!
I've developed a framework for testing compilers that might be of use. Each test is a file to be parsed which contains (as comments) the expected result. See http://www.engr.mun.ca/~theo/Publications/compiler-testing.pdf for details. I can send you the code for the testing framework, if you'd like.
To your specific question, I'm not sure how you could go about testing the .jj file directly. The only option I see is to test the generated lexer and parser to see if they behave as desired. Of course that assumes that someone has regenerated the .java files since the last change to the .jj file.
I'm trying to add some unit tests to an existing code base using Visual Studio 2010's unit test generator. However, in some cases when I open a class, right click --> Create Unit Tests..., after I select the methods to generate tests for it will create what is essentially a blank test. Are there situations where this can happen? In every case I select at least one public method to gen tests for, and all it generates is this:
using TxRP.Controllers; //The location of the code to be tested
using Microsoft.VisualStudio.TestTools.UnitTesting;
That's it. Nothing else. Strange, right?
I should note that this is all MVC 2 controller code, and I have been able to gen tests for other controllers with no problem, and all my controllers follow pretty much the same format. No error seems to be thrown, as it gens the empty page happily and adds it to the project as if everything is just fine.
Has anyone had experience with the same type of thing happening, and was there any answer found as to why?
UPDATE:
There is in fact an error during generation:
While trying to generate your tests, the following errors occurred:
Value cannot be null.
Parameter name: key
After some research, the only possible solution I found is that this error occurrs if you're trying to generate tests to a test file that already exists. However, this solution is not working for me...
If you try to generate tests for a class which already has existing tests in another file in the project, it will just generate an empty file as described above. Changing the filename is not sufficient, nor is using a different location within the project. Basically it seems to enforce the one-testfile-per-class convention across the entire project.
This problem is caused by the previously generated test file having been moved to a folder other than the root folder in the test project.
Resolution
Move the test file into the test project root folder.
Generate the new tests
Move the test file back to the folder location you want in the test project.
I have no clue why they dont call it a BUG! in a typical enterprise level software development it is more than a coincidence where multiple people generate unit tests for different methods of the same class # different points of time.
We always end up with this error and it is not helping us any way! Feels as if the Context Menu "Create Unit Tests" has lil use!
Error description:
"While trying to generate your tests, the following errors occurred:
Value cannot be null.
Parameter name: key
"
In CPP unit we run unit test as part of build as part of post build setup. We will be running multiple tests as part of this. In case if any test case fails post build should not stop, it should go ahead and run all the test cases and should report summary how many test cases passed and failed. how can we achieve this.
Thanks!
His question is specific enough. You need a test runner. Encapsulate each test in its own behavior and class. The test project is contained separately from the tested code. Afterwards just configure your XMLOutputter. You can find an excellent example of how to do this in the linux website. http://www.yolinux.com/TUTORIALS/CppUnit.html
We use this way to compile our test projects for our main projects and observe if everything is ok. Now it all becomes the work of maintaining your test code.
Your question is too vague for a precise answer. Usually, a unit test engine return a code to tell it has failed (like a non zero return code in the shell on linux) or generate some output file with results. The calling system handle this. If you have written it (some home made scripts) you have to give the option to go on tests execution even if an error occurred. If you are using some tools like continuous integration server, then you have to go through the doc and find the option that allows you to go on when tests fails.
A workaround is to write a script that return a "OK" result even if the unit test fails, but there you lose some automatic verification ...
Be more specific if you want more clues.
my2c
I would just write your tests this way. Instead of using the CPPUNIT_ASSERT macros or whatever you would write them in regular C++ with some way of logging errors.
You could use a macro for this too of course. Something like:
LOGASSERT( some_expression )
could be defined to execute some_expression and to log the expression together with FILE and LINE if it fails, and you can also log exceptions of course, as well as ones that are not thrown, simply by writing them in your tests (with macros if you want to log the expression that caused them with FILE and LINE).
If you are writing macros I would advise you to limit the content of your macro to calling an inline function with extra parameters.
I just started writing tests for a lot of code. There's a bunch of classes with dependencies to the file system, that is they read CSV files, read/write configuration files and so on.
Currently the test files are stored in the test directory of the project (it's a Maven2 project) but for several reasons this directory doesn't always exist, so the tests fail.
Do you know best practices for coping with file system dependencies in unit/integration tests?
Edit: I'm not searching an answer for that specific problem I described above. That was just an example. I'd prefer general recommendations how to handle dependencies to the file system/databases etc.
First one should try to keep the unit tests away from the filesystem - see this Set of Unit Testing Rules. If possible have your code working with Streams that will be buffers (i.e. in memory) for the unit tests, and FileStream in the production code.
If this is not feasible, you can have your unit tests generates the files they need. This makes the test easy to read as everything is in one file. This may also prevent permissions problem.
You can mock the filesystem/database/network access in your unit tests.
You can consider the unit tests that rely on DB or file systems as integration tests.
Dependencies on the filesystem come in two flavours here:
files that your tests depend upon; if you need files to run the test, then you can generate them in your tests and put them in a /tmp directory.
files that your code is dependent upon: config files, or input files.
In this second case, it is often possible to re-structure your code to remove dependency on a file (e.g. java.io.File can be replaced with java.io.InputStream and java.io.OutputStream, etc.) This may not be possible of course.
You may also need to handle 'non-determinism' in the filesystem (I had a devil of a job debugging something on an NFS once). In this case you should probably wrap the file system in a thin interface.
At its simplest, this is just helper methods that take a File and forward the call onto that file:
InputStream getInputStream(File file) throws IOException {
return new FileInputStream(file);
}
You can then replace this one with a mock which you can direct to throw the exception, or return a ByteArrayInputStream, or whatever.
The same can be said for URLs and URIs.
There are two options for testing code that needs to read from files:
Keep the files related to the unit tests in source control (e.g. in a test data folder), so anyone who gets the latest and runs the tests always has the relevant files in a known folder relative to the test binaries. This is probably the "best practice".
If the files in question are huge, you might not want to keep them in source control. In this case, a network share that is accessible from all developer and build machines is probably a reasonable compromise.
Obviously most well-written classes will not have hard dependencies on the file system in the first place.
Usually, file system tests aren't very critical: The file system is well understood, easy to set up and to keep stable. Also, accesses are usually pretty fast, so there is no reason per se to shun it or to mock the tests.
I suggest that you find out why the directory doesn't exist and make sure that it does. For example, check the existence of a file or directory in setUp() and copy the files if the check fails. This only happens once, so the performance impact is minimal.
Give the test files, both in and out, names that are structurally similar to the unit test name.
In JUnit, for instance, I'd use:
File reportFile = new File("tests/output/" + getClass().getSimpleName() + "/" + getName() + ".report.html");
I'm working on a C++ library that (among other stuff) has functions to read config files; and I want to add tests for this. So far, this has lead me to create lots of valid and invalid config files, each with only a few lines that test one specific functionality. But it has now got very unwieldy, as there are so many files, and also lots of small C++ test apps. Somehow this seems wrong to me :-) so do you have hints how to organise all these tests, the test apps, and the test data?
Note: the library's public API itself is not easily testable (it requires a config file as parameter). The juicy, bug-prone methods for actually reading and interpreting config values are private, so I don't see a way to test them directly?
So: would you stick with testing against real files; and if so, how would you organise all these files and apps so that they are still maintainable?
Perhaps the library could accept some kind of stream input, so you could pass in a string-like object and avoid all the input files? Or depending on the type of configuration, you could provide "get/setAttribute()" functions to directly, publicy, fiddle the parameters. If that is not really a design goal, then never mind. Data-driven unit tests are frowned upon in some places, but it is definitely better than nothing! I would probably lay out the code like this:
project/
src/
tests/
test1/
input/
test2
input/
In each testN directory you would have a cpp file associated to the config files in the input directory.
Then, assuming you are using an xUnit-style test library (cppunit, googletest, unittest++, or whatever) you can add various testXXX() functions to a single class to test out associated groups of functionality. That way you could cut out part of the lots-of-little-programs problem by grouping at least some tests together.
The only problem with this is if the library expects the config file to be called something specific, or to be in a specific place. That shouldn't be the case, but if it is would have to be worked around by copying your test file to the expected location.
And don't worry about lots of tests cluttering your project up, if they are tucked away in a tests directory then they won't bother anyone.
Part 1.
As Richard suggested, I'd take a look at the CPPUnit test framework. That will drive the location of your test framework to a certain extent.
Your tests could be in a parallel directory located at a high-level, as per Richard's example, or in test subdirectories or test directories parallel with the area you want to test.
Either way, please be consistent in the directory structure across the project! Especially in the case of tests being contained in a single high-level directory.
There's nothing worse than having to maintain a mental mapping of source code in a location such as:
/project/src/component_a/piece_2/this_bit
and having the test(s) located somewhere such as:
/project/test/the_first_components/connection_tests/test_a
And I've worked on projects where someone did that!
What a waste of wetware cycles! 8-O Talk about violating the Alexander's concept of Quality Without a Name.
Much better is having your tests consistently located w.r.t. location of the source code under test:
/project/test/component_a/piece_2/this_bit/test_a
Part 2
As for the API config files, make local copies of a reference config in each local test area as a part of the test env. setup that is run before executing a test. Don't sprinkle copies of config's (or data) all through your test tree.
HTH.
cheers,
Rob
BTW Really glad to see you asking this now when setting things up!
In some tests I have done, I have actually used the test code to write the configuration files and then delete them after the test had made use of the file. It pads out the code somewhat and I have no idea if it is good practice, but it worked. If you happen to be using boost, then its filesystem module is useful for creating directories, navigating directories, and removing the files.
I agree with what #Richard Quirk said, but also you might want to make your test suite class a friend of the class you're testing and test its private functions.
For things like this I always have a small utility class that will load a config into a memory buffer and from there it gets fed into the actually config class. This means the real source doesn't matter - it could be a file or a db. For the unit-test it is hard coded one in a std::string that is then passed to the class for testing. You can simulate currup!pte3d data easily for testing failure paths.
I use UnitTest++. I have the tests as part of the src tree. So:
solution/project1/src <-- source code
solution/project1/src/tests <-- unit test code
solution/project2/src <-- source code
solution/project2/src/tests <-- unit test code
Assuming that you have control over the design of the library, I would expect that you'd be able to refactor such that you separate the concerns of actual file reading from interpreting it as a configuration file:
class FileReader reads the file and produces a input stream,
class ConfigFileInterpreter validates/interprets etc. the contents of the input stream
Now to test FileReader you'd need a very small number of actual files (empty, binary, plain text etc.), and for ConfigFileInterpreter you would use a stub of the FileReader class that returns an input stream to read from. Now you can prepare all your various config situations as strings and you would not have to read so many files.
You will not find a unit testing framework worse than CppUnit. Seriously, anybody who recommends CppUnit has not really taken a look at any of the competing frameworks.
So yes, go for a unit testing franework, but do not use CppUnit.