In order to keep our codebase healthy, the Dataverse project encourages developers to write automated tests in the form of unit tests and integration tests. We also welcome ideas for how to improve our automated testing.
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Before we dive into the nut and bolts of testing, let’s back up for a moment and think about why we write automated tests in the first place. Writing automated tests is an investment and leads to better quality software. Counterintuitively, writing tests and executing them regularly allows a project to move faster. Martin Fowler explains this well while talking about the health of a codebase:
“This is an economic judgment. Several times, many times, I run into teams that say something like, ‘Oh well. Management isn’t allowing us to do a quality job here because it will slow us down. And we’ve appealed to management and said we need to put more quality in the code, but they’ve said no, we need to go faster instead.’ And my comment to that is well, as soon as you’re framing it in terms of code quality versus speed, you’ve lost. Because the whole point of refactoring is to go faster.
“And this is why I quite like playing a bit more with the metaphor as the health of a codebase. If you keep yourself healthy then you’ll be able to run faster. But if you just say, ‘Well, I want to run a lot so I’m therefore going to run a whole load all the time and not eat properly and not pay attention about this shooting pain going up my leg,’ then you’re not going to be able to run quickly very long. You have to pay attention to your health. And same with the codebase. You have to continuously say, ‘How do we keep it in a healthy state? Then we can go fast,’ because we’re running marathons here with codebases. And if we neglect that internal quality of the codebase, it hits you surprisingly fast.“
—Martin Fowler at https://devchat.tv/ruby-rogues/178-rr-book-club-refactoring-ruby-with-martin-fowler
Security in depth might mean that your castle has a moat as well as high walls. Likewise, when testing, you should consider testing a various layers of the stack using both unit tests and integration tests.
When writing tests, you may find it helpful to first map out which functions of your code you want to test, and then write a functional unit test for each which can later comprise a larger integration test.
Creating unit tests for your code is a helpful way to test what you’ve built piece by piece.
Unit tests can be executed without runtime dependencies on PostgreSQL, Solr, or any other external system. They are the lowest level of testing and are executed constantly on developers’ laptops as part of the build process and via continous integration services in the cloud.
A unit test should execute an operation of your code in a controlled fashion. You must make an assertion of what the expected response gives back. It’s important to test optimistic output and assertions (the “happy path”), as well as unexpected input that leads to failure conditions. Know how your program should handle anticipated errors/exceptions and confirm with your test(s) that it does so properly.
We use a variety of tools to write, execute, and measure the code coverage of unit tests, including Maven, JUnit, Jacoco, GitHub, Travis, and Coveralls. We’ll explain the role of each tool below, but here’s an overview of what you can expect from the automation we’ve set up.
As you prepare to make a pull request, as described in the Version Control section, you will be working on a new branch you create from the “develop” branch. Let’s say your branch is called 1012-private-url. As you work, you are constantly invoking Maven to build the war file. When you do a “clean and build” in Netbeans, Maven runs all the unit tests (anything ending with Test.java) and the runs the results through a tool called Jacoco that calculates code coverage. When you push your branch to GitHub and make a pull request, a web service called Travis CI runs Maven and Jacoco on your branch and pushes the results to Coveralls, which is a web service that tracks changes to code coverage over time.
To make this more concrete, observe that https://github.com/IQSS/dataverse/pull/3111 has comments from a GitHub user called coveralls saying things like “Coverage increased (+0.5%) to 5.547% when pulling dd6ceb1 on 1012-private-url into be5b26e on develop.” Clicking on the comment should lead you to a URL such as https://coveralls.io/builds/7013870 which shows how code coverage has gone up or down. That page links to a page such as https://travis-ci.org/IQSS/dataverse/builds/144840165 which shows the build on the Travis side that pushed the results ton Coveralls.
The main takeaway should be that we care about unit testing enough to measure the changes to code coverage over time using automation. Now let’s talk about how you can help keep our code coverage up by writing unit tests with JUnit.
We are aware that there are newer testing tools such as TestNG, but we use JUnit because it’s tried and true.
If writing tests is new to you, poke around existing unit tests which all end in Test.java and live under src/test. Each test is annotated with @Test and should have at least one assertion which specifies the expected result. In Netbeans, you can run all the tests in it by clicking “Run” -> “Test File”. From the test file, you should be able to navigate to the code that’s being tested by right-clicking on the file and clicking “Navigate” -> “Go to Test/Tested class”. Likewise, from the code, you should be able to use the same “Navigate” menu to go to the tests.
Existing code is not necessarily written in a way that lends itself to easy testing. Generally speaking, it is difficult to write unit tests for both JSF “backing” beans (which end in Page.java) and “service” beans (which end in Service.java) because they require the database to be running in order to test them. If service beans can be exercised via API they can be tested with integration tests (described below) but a good technique for making the logic testable it to move code to “util beans” (which end in Util.java) that operate on Plain Old Java Objects (POJOs). PrivateUrlUtil.java is a good example of moving logic from PrivateUrlServiceBean.java to a “util” bean to make the code testable.
Once you’ve written some tests, you’re probably wondering how much you’ve helped to increase the code coverage. In Netbeans, do a “clean and build.” Then, under the “Projects” tab, right-click “dataverse” and click “Code Coverage” -> “Show Report”. For each Java file you have open, you should be able to see the percentage of code that is covered by tests and every line in the file should be either green or red. Green indicates that the line is being exercised by a unit test and red indicates that it is not.
In addition to seeing code coverage in Netbeans, you can also see code coverage reports by opening target/site/jacoco/index.html in your browser.
You might find studying the following test classes helpful in writing tests for commands:
In addition, there is a writeup on “The Testable Command” at https://github.com/IQSS/dataverse/blob/develop/doc/theTestableCommand/TheTestableCommand.md .
Unit tests are fantastic for low level testing of logic but aren’t especially real-world-applicable because they do not exercise Dataverse as it runs in production with a database and other runtime dependencies. We test in-depth by also writing integration tests to exercise a running system.
Unfortunately, the term “integration tests” can mean different things to different people. For our purposes, an integration test has the following qualities:
Unit tests are run automatically on every build, but dev environments and servers require special setup to run REST Assured tests. In short, Dataverse needs to be placed into an insecure mode that allows arbitrary users and datasets to be created and destroyed. This differs greatly from the out-of-the-box behavior of Dataverse, which we strive to keep secure for sysadmins installing the software for their institutions in a production environment.
The Development Environment section currently refers developers here for advice on getting set up to run REST Assured tests, but we’d like to add some sort of “dev” flag to the installer to put Dataverse in “insecure” mode, with lots of scary warnings that this dev mode should not be used in production.
For reasons that have been lost to the mists of time, Dataverse really wants you to to have a burrito. Specifically, if you’re trying to run REST Assured tests and see the error “Dataverse config issue: No API key defined for built in user management”, you must run the following curl command (or make an equivalent change to your database):
curl -X PUT -d 'burrito' http://localhost:8080/api/admin/settings/BuiltinUsers.KEY
Without this “burrito” key in place, REST Assured will not be able to create users. We create users to create objects we want to test, such as dataverses, datasets, and files.
In your browser, log in as dataverseAdmin (password: admin) and click the “Edit” button for your root dataverse. Navigate to Permissions, then the Edit Access button. Under “Who can add to this dataverse?” choose “Anyone with a dataverse account can add sub dataverses” if it isn’t set to this already.
Alternatively, this same step can be done with this script: scripts/search/tests/grant-authusers-add-on-root
The root dataverse must be published for some of the REST Assured tests to run.
When run locally (as opposed to a remote server), some of the REST Assured tests require the dataverse.siteUrl JVM option to be set to http://localhost:8080. See “JVM Options” under the Configuration section of the Installation Guide for advice changing JVM options. First you should check to check your JVM options with:
asadmin list-jvm-options | egrep 'dataverse|doi'
If dataverse.siteUrl is absent, you can add it with:
asadmin create-jvm-options "-Ddataverse.siteUrl=http\://localhost\:8080"
DatasetsIT.java exercises the feature where the “identifier” of a DOI can be a digit and requires a sequence to be added to your database. See :IdentifierGenerationStyle under the Configuration section for adding this sequence to your installation of PostgreSQL.
Before writing any new REST Assured tests, you should get the tests to pass in an existing REST Assured test file. BuiltinUsersIT.java is relatively small and requires less setup than other test files.
You do not have to reinvent the wheel. There are many useful methods you can call in your own tests – especially within UtilIT.java – when you need your test to create and/or interact with generated accounts, files, datasets, etc. Similar methods can subsequently delete them to get them out of your way as desired before the test has concluded.
For example, if you’re testing your code’s operations with user accounts, the method UtilIT.createRandomUser(); can generate an account for your test to work with. The same account can then be deleted by your program by calling the UtilIT.deleteUser(); method on the imaginary friend your test generated.
Remember, it’s only a test (and it’s not graded)! Some guidelines to bear in mind:
To execute existing integration tests on your local Dataverse, a helpful command line tool to use is Maven. You should have Maven installed as per the Development Environment guide, but if not it’s easily done via Homebrew: brew install maven.
Once installed, you may run commands with mvn [options] [<goal(s)>] [<phase(s)>].
If you want to run just one particular API test, it’s as easy as you think:
mvn test -Dtest=FileRecordJobIT
To run more than one test at a time, separate by commas:
mvn test -Dtest=FileRecordJobIT,ConfirmEmailIT
To run any test(s) on a particular domain, replace localhost:8080 with desired domain name:
mvn test -Dtest=FileMetadataIT -Ddataverse.test.baseurl='http://localhost:8080'
A server at http://phoenix.dataverse.org has been set up to test the latest code from the develop branch. Testing is done using chained builds of Jenkins jobs:
We’d like to make improvements to our automated testing. See also ‘this thread from our mailing list <https://groups.google.com/forum/#!topic/dataverse-community/X8OrRWbPimA>’_ asking for ideas from the community, and discussion at ‘this GitHub issue. <https://github.com/IQSS/dataverse/issues/2746>’_
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