Development testing is done to make sure that the future Member Node is ready for real-world testing in the staging environment. This includes testing for correct method responses under different circumstances, making sure that metadata and resource maps parse and are usable, and that the formats used by the node are registered.
To accomplish this, DataONE has developed a suite of tests that are used to test our own Member Node implementations. For convenience, we have deployed these tests as a web-based Member Node testing service. Those already familiar with Maven and JUnit may instead wish to download the tests from our code repository and run the tests locally. Passing all of the required tests will signal readiness to enter the deployment phase.
While Member Node developers are encouraged to run the MN testing service at any point in their internal development process, the primary source of guidance on how to implement a method should be the DataONE architecture documentation and API reference. When troubleshooting failed tests, in general, careful rereading of the method documentation in the context of the failure message is the best way to understand what exactly went wrong, as well as looking at the source code of the test. Developers are also welcome to contact the DataONE development team for more information and explanation.
Multiple versions of the testers are maintained, corresponding to the major.minor versions of the published API. Within each tester, the testing service is organized by Tier, so that Tier1 API methods are tested before Tier2 methods, and so on. Results are also organized by tier, and a summary for each subset of tests is given. If you are planning to deploy a Tier 1 node, then of course only worry about testing and passing Tier 1 methods.
Requirements for testing vary from tier to tier. Most tests rely on existing content, except MN_Storage methods, which need to test the create, update, and archive methods. Below are listed the general content related requirements for each Tier.
Most of the Tier1 tests rely on listObjects to get an identifier that can be used to run Tier 1 tests. So, Tier 1 nodes need to have at least one object. Tier 1 also tests that resource maps can be parsed, so if there is only one object, it should be a resource map. Ideally, a member node would have a representative object for all of the data formats it has objects of.
The bulk of Tier 2 testing is testing data security, and so the member node needs to load a set of objects with the pre-defined access policies.
TODO: make the test objects available as a download.
If you are implementing a Tier 3 node, you do not need to start with any content in the node to test Tier 1 and 2 methods. Instead, the testers will create the data objects they need, provided that the create method is working properly.
You will probably, however, wish to clear out the test objects if the node under test is going into production.
TODO: instructions on how to identify these objects (they all have the same owner, I believe)
Tier 4 tests are limited to testing exception handling, since most of this functionality requires interaction with Coordinating nodes and other member nodes.
Tests can fail for many reasons, so the best a failure message can hope to do is be clear about the circumstances that caused the failure, and provide relevant diagnostic information. Each failure message is composed of the following parts:
- The failure description
- REST call details
- stack trace
Of the three, the failure description is the most useful for understanding the what failed. In some cases the description is the exception thrown (Class name:: detail code: http status: exception message), and in other cases it is just a message explaining the failure.
The REST call details are useful for recreating the call that resulted in a failure. Remembering that many tests (especially in Tier1) first call listObjects to get an identifier to work with for the main test, do not be surprised to see a problem in listObjects even if the test is for another method. Also note that in cases where it is known that the failure is client-side (not server side), the REST call is usually not provided.
The stack trace is there to debug client-side exceptions, or to find the spot in the client code that where an exception was thrown. Usually, this only helpful with content related problems.
For the methods that take an Identifier in the URL of the method call, identifier encoding tests are performed to make sure that the Member Node can handle the encoded identifiers properly. About 30 identifiers using characters from different ranges of the Unicode standard are tested against each of these methods.
If one example fails, the entire test fails, and you will need to do some detective work to find out the problem. Comparing suspicious characters in the failing identifier to characters in the passing examples can help to narrow the problem. Also, in the name of the identifier itself is a terse indication of the types of characters being tested, and in one case, the word ‘tomcat’ is used as it was first found to be problematic with certain tomcat web server configurations.