Best way to reset database to known state between FlexUnit4 integration tests? - java

Background:
I have a Flex web app that communicates with a Java back-end via BlazeDS. The Flex client is composed of a flex-client module, which holds the views and presentation models and a separate flex-service module which holds the models (value objects) and service objects.
I am in the process of writing asynchronous integration tests for the flex-service module's RemoteObjects using FlexUnit4. In some of the tests, I modify the test data and query it back to see if everything works (a technique shown here: http://saturnboy.com/2010/02/async-testing-with-flexunit4)
Question:
How do I go about resetting the database to a known state before each FlexUnit4 test method (or test method chain)? In my Java server integration tests, I did this via a combination of DBUnit and Spring Test's transactions -- which rollback after each test method. But these Flexunit integration span multiple requests and thus multiple transactions.
Short of implementing an integration testing service API on the backend, how can this be accomplished. Surely others have run into this as well? Similar questions have been asked before ( Rollback database after integration (Selenium) tests ), but with no satisfactory answers.

There are several options:
If you use sequences for primary keys: After the database has been loaded with the test data, delete the sequence generator and replace it with one that starts with -1 and counts down. After the test, you can delete objects with a primary key < 0. Breaks for tests which modify existing data.
A similar approach is to create a special user or, if you have created timestamp columns, then the initial data must be before some date in the past. That needs additional indexes, though.
Use a database on the server which can be quickly wiped (H2, for example). Add a service API which you can call from the client to reset the DB.
Add undo to your web app. That's quite an effort but a very cool feature.
Use a database which allows to move back in time with a single command, like Lotus Notes.
Don't use a database at all. Instead write a proxy server which will respond to the correct input with the correct output. Add some code to your real server to write the data exchanged into a file and create your tests from that.
Or write test cases which run against the real server and which create these files. That will allow you to track which files change when you modify code on the server or client.
On the server, write tests which make sure that it will do the correct DB modifications.
Similar to "no database at all", hide all code which accesses the DB in a DB layer and use interfaces to access it. This allows you to write a mock-up layer which behaves like the real database but which saves the data in memory. Sounds simple but is usually a whole lot of work.

Depending on the size of your test database, you could automate clean backups/restores that gives you the exact environment you had on each test run.
I've that approach in on of my current projects (different platform) and we also test data schema change scripts with the same approach.

I'm dehydrated (my fav excuse for short-comings). So sorry if this answer is too close to the "integration testing service API on the backend" response that you didn't want.
The team that set-up flexUnit 'ages ago' made choices and created solutions based on our architecture, some of which would only apply to our infrastructure. Things to consider:
1) all of our backend methods return the same remotely-mapped class. 2) most all of our methods have an abstracted method that telling the method to (or not to) run a "begin transaction" at the beginning of the method and a "commit transaction" at the end (not sure of your db chunk).
The latter isn't probably the most object oriented solution, but here's what an asynchronous unit-test call does: Every unit test calls the same method-wrapper, and we pass-in the method-name/package-locale, plus the [...]args. A beginTransaction is done. The method is called, passing a false to the method for FE unit tests (to ignore the beginTransaction and commitTransaction lines), everything is run and the main 'response' class is generated and returned to the unit test method. A db-rollback is run and the response is returned to the unit test.
All of our unit tests are based on rolling-back transactions. I couldn't tell you of the issues that they had when setting up that jive, but that's my general understanding of how schtuff works.
Hope that helps. Understandable if it doesn't.
Best of luck,
--jeremy

Related

How to set up initial test data in database Java project? (possibly not using raw SQL statements)

I’m creating new automated tests java project. This will be mainly selenium test (selenide) + API test (Rest assured).
I would like to integrate those tests with application DB.
By integrate I mean:
I can setup initial application state in every test in “Given” context.
For a background, previously I made C# test project using: https://bitbucket.org/mk_meros/databag/wiki/Home this allowed me to make classes each represent different tables. Then I could use it in Given step implementation to insert data directly to DB and create initial test data. Each tests had ONE common initial app state + possibly his own Given Exists custom data, after test end data was cleared from DB, and another test was creating his own initial setup.
Can I find something similar to use in Java project?
Limitation od databag is only integration with Entity Framework.
You should have a look at DBUnit, which should be an answer to your problem.

Rollback Database after running Selenium GUI tests

I am using Selenium GUI tests in a Java Web Application.
Since these tests are actually client, how can we rollback database after running a test?
What you're after is called Fixture Teardown Patterns. Since you need to keep track of all resources that are created in a test and automatically destroy/free them during Teardown. I obviously don't know your framework, but for this case
rollback database after running a test
a good candidate is the Inline Teardown. It includes teardown logic at the end of the Test Method immediately after the result verification. Like so:
My guess is that you can't 'roll back' the database since web applications typically commit transactions between requests.
You'll need to implement your own custom rollback. Perhaps you could create a new user for each test and remove any changes made by this user after the test. Or maybe you want to implement the command pattern.
You might also find a cascading delete helpful
Lately I attended a talk about docker. The speaker was creating a docker container with a mysql database for demonstration purposes. I was immediately thinking about how to use this for integration testing as you can create a clean database instance with very little effort.
I was searching if there are already some best practices and found those to websites
TestContainers - pay attention to the Temporary database containers link
Tutorial – Docker, JPA and Testing - a complete example
I´m in the phase of evaluating on how to integrate this but I´m confident this is what I (and hopefully you) was looking for.
Workflow would be:
Test execution
Start docker container from image with empty
Fill database with master data (if necessary)
Run test
Throw docker container away
Thank you for your suggestions.
I decided to use mysqldump for this purpose. Within Ant, Backup and restore the test-database before and after each batch-test.

Tools and Methods for testing Service/DAO layers in Java

I am trying to figure out the best way(s) to test Service and DAO layers. So, a few sub questions...
When testing a service layer, is it best to test against a mock DAO layer or a "live" DAO layer pointed at a testing environment?
How should SQL in the DAO layer be tested when the only test database is in a shared environment (Oracle/DB2)
How do you solve the paradox of any DAO writes/updates need to be tested with DAO reads which is something that also has to be tested?
I am looking for any good documentation, articles, or references in this area along with any tools to help automate the process. I already know about JUint for unit testing and Hudson for CI.
Get Growing Object-Oriented Software, Guided by Tests. It has some great tips about how to test database access.
Personally, I usually break the DAO tests in 2, a unit test with a mocked database to test functionality on the DAO, and an integration test, to test the queries against the DB. If your DAO only has database access code, you won't need a unit test.
One of the suggestions from the book that I took, is that the (integration) test has to commit the changes to the DB. I've learn to do this, after using hibernate and figuring out that the test was marked for rollback and the DB never got the insert statement. If you use triggers or any kind of validation (even FKs) I think this is a must.
Another thing, stay away from dbunit, it's a great framwork to start working, but it becomes hellish when a project becomes something more than tiny. My preference here, is to have a set of Test Data Builder classes to create the data, and insert it in the setup of the test or in the test itself.
And check dbmigrate, it's not for testing, but it will help you to manage scripts to upgrade and downgrade your DB schema.
In the scenario where the DB server is shared, I've creates one schema/user per environment. Since each developer has his own "local" environment, he also owns one schema.
Here are my answers :
Use mock DAOs to test your services. Much easier, mush faster. Use EasyMock or Mockito or any other mock framework to test the service layer.
Give each developer its own database schema to execute his tests. Such schemas are typically empty : the unit tests populate the database with a small test data set before running a test, and empties it once the test is completed. Use DBUnit for this.
If the reads work against a well-defined, static, test data set (which you should unit-test), then you can rely on them to unit-test the writes. But you can also use ad-hoc queries or even DBUnit to test that the writes work as expected. The fact that the tests are not necessarily run in this order doesn't matter. If everything passes, then everything is OK.

Mocking a StoredProcedure

I am soon writing a unit test to a service tier-class that relies heavily to org.springframework.jdbc.object.StoredProcedure class.
The service object is going to be simple batch class, reading data from a stored-procedure, aggregating it and sending it to a another stored-procedure.
What would be a best practice regarding such an unit test (since it relies heavily to a database). Should I use a fake object (set of method stubs), write a mock with a database backend or mirror the real thing (with the cost of keeping the infrastructure up to date)?
I want be as lazy as possible and still guarantee quality.
Personally, I would do the unit tests in a case like this with an embedded database like H2.
Hope this helps.
I would not worry about testing end-to-end in this case. I would stub out the calls to the stored proc and make sure your code works as expected.
The next thing to do is test the stored proc. If you are on an oracle platform then you can test-drive the proc using ruby-plsql. I have used this on a project before and it works well. If you are not on an oracle platform then you are going to have to build something in your test harness that can call the stored proc in such ways that you will see the different outcomes. Just shoot for the happy path and a few edge cases.

End to End testing of Webservices

first time poster and TDD adopter. :-) I'll be a bit verbose so please bear with me.
I've recently started developing SOAP based web services using the Apache CXF framework, Spring and Commons Chain for implementing business flow. The problem I'm facing here is with testing the web services -- testing as in Unit testing and functional testing.
My first attempt at Unit testing was a complete failure. To keep the unit tests flexible, I used a Spring XML file to keep my test data in. Also, instead of creating instances of "components" to be tested, I retrieved them from my Spring Application context. The XML files which harbored data quickly got out of hand; creating object graphs in XML turned out to be a nightmare. Since the "components" to be tested were picked from the Spring Application Context, each test run loaded all the components involved in my application, the DAO objects used etc. Also, as opposed to the concept of unit test cases being centralized or concentrated on testing only the component, my unit tests started hitting databases, communicating with mail servers etc. Bad, really bad.
I knew what I had done wrong and started to think of ways to rectify it. Following an advice from one of the posts on this board, I looked up Mockito, the Java mocking framework so that I could do away with using real DAO classes and mail servers and just mock the functionality.
With unit tests a bit under control, this brings me to my second problem; the dependence on data. The web services which I have been developing have very little logic but heavy reliance on data. As an example, consider one of my components:
public class PaymentScheduleRetrievalComponent implements Command {
public boolean execute(Context ctx) {
Policy policy = (Policy)ctx.get("POLICY");
List<PaymentSchedule> list = billingDAO.getPaymentStatementForPolicy(policy);
ctx.put("PAYMENT_SCHEDULE_LIST", list);
return false;
}
}
A majority of my components follow the same route -- pick a domain object from the context, hit the DAO [we are using iBatis as the SQL mapper here] and retrieve the result.
So, now the questions:
- How are DAO classes tested esp when a single insertion or updation might leave the database in a "unstable" state [in cases where let's say 3 insertions into different tables actually form a single transaction]?
- What is the de-facto standard for functional testing web services which move around a lot of data i.e. mindless insertions/retrievals from the data store?
Your personal experiences/comments would be greatly appreciated. Please let me know in case I've missed out some details on my part in explaining the problem at hand.
-sasuke
I would stay well away from the "Context as global hashmap" 'pattern' if I were you.
Looks like you are testing your persistence mapping...
You might want to take a look at: testing persistent objects without spring
I would recommend an in-memory database for running your unit tests against, such as HSQL. You can use this to create your schema on the fly (for example if you are using Hibernate, you can use your XML mappings files), then insert/update/delete as required before destroying the database at the end of your unit test. At no time will your test interfere with your actual database.
For you second problem (end-to-end testing of web services), I have successfully unit tested CXF-based services in the past. The trick is to publish your web service using a light-weight web server at the beginning of your test (Jetty is ideal), then use CXF to point a client to your web service endpoint, run your calls, then finally shut down the Jetty instance hosting your web service once your unit test has completed.
To achive this, you can use the JaxWsServerFactoryBean (server-side) and JaxWsProxyFactoryBean (client-side) classes provided with CXF, see this page for sample code:
http://cwiki.apache.org/CXF20DOC/a-simple-jax-ws-service.html#AsimpleJAX-WSservice-Publishingyourservice
I would also give a big thumbs up to SOAP UI for doing functional testing of your web service. JMeter is also extremely useful for stress testing web services, which is particularity important for those services doing database lookups.
First of all: Is there a reason you have to retrieve the subject under test (SUT) from the Spring Application context? For efficient unit testing you should be able to create the SUT without the context. It sounds like you have some hidden dependencies somewhere. That might be the root of some of your headache.
How are DAO classes tested esp when a
single insertion or updation might
leave the database in a "unstable"
state [in cases where let's say 3
insertions into different tables
actually form a single transaction]?
It seems you are worried about the database's constistency after you have running the tests. If possible use a own database for testing, where you don't need care about it. If you have such a sandbox database you can delete data as you wish. In this case I would do the following:
Flag all your fake data with some common identifier, like putting a special prefix to a field.
Before running the test drop a delete statement, which deletes the flagged data. If there is none, then nothing bad happens.
Run your single DAO test. After that repeat step 2. for the next test.
What is the de-facto standard for
functional testing web services which
move around a lot of data i.e.
mindless insertions/retrievals from
the data store?
I am not aware of any. From the question your are asking I can infer that you have on one side the web service and on the other side the database. Split up the responsibilities. Have separate test suites for each side. One side just testing database access (as described above). On the other side just testing web service requests and responses. In this case it pays of the stub/fake/mock the layer talking to the network. Or consider https://wsunit.dev.java.net/.
If the program is only shoving data in and out I think that there is not much behavior. If this is the case, then the hardest work is to unit test the database side and the web service side. The point is you can do unit testing without the need for "realistic" data. For functional testing you will need handrolled data, which is close to reality. This might be cumbersome, but if you already unit tested the database and web service parts intensively, this should reduce the need for "realistic" test cases considerably.
First of all, make thing clear.
In an ideal world the lifecycle of the software your are building is something like this:
- sy makes a report with the customer, so you got an user story with examples about how the application should work
- you generalize the user story, so you got rules, which you call as use cases
- you start to write a piece of functional (end to end) test, and it fails...
- after that your build the ui and mock out the services, so you got a green functional test and a specification about how your services should work...
- your job is to keep the functional test green, and implement the services step by step writing integration tests, and mocking out dependencies with the same approach until you reach the level of unit tests
- after that you do the next iteration with the use cases, write the next piece of functional test, and so on until the end of the project
- after that you make acceptance tests with the customer who accepts the product and pays a lot
So what did we learn from this:
There are many types of tests (don't confuse them with each other)
functional tests - for testing the use cases (mock out nothing)
integration tests - for testing application, component, module, class interactions (mock out the irrelevant components)
unit tests - for testing a single class in isolation from its environment (mock out everything)
user acceptance tests - customer makes sure, that she accepts the product (manual functional tests, or presentation made from automatic functional tests in working)
You don't need to test everything by functional tests and integration tests, because it is impossible. Test only the relevant part by functional and integration tests and test everything by unit tests! Familiarize yourself with the testing pyramid.
Use TDD, it makes life easier!
How are DAO classes tested esp when a single insertion or updation might leave the database in a "unstable" state [in cases where let's
say 3 insertions into different tables actually form a single
transaction]?
You don't have to test your database transactions. Assume, that they are working well, because database developers have already tested them, and I am sure you don't want to write concurrency tests... Db is an external component, so you don't have to test it yourself. You can write a data access layer to adapt the data storage to your system, and write integration tests only for those adapters. In case of database migration these tests will work by the adapters of the new database as well, because your write them to implement a specific interface... By any other tests (except functional tests) you can mock out your data access layer. Do the same with every other external component as well, write adapters and mock them out. Put these kind of integration tests to a different test suite than the other tests, because they are slow because of database access, filesystem access, etc...
What is the de-facto standard for functional testing web services which move around a lot of data i.e. mindless insertions/retrievals
from the data store?
Your can mock out your data store with an in memory db which implements the same storage adapters until you implemented everything else except the database. After that your implement the data access layer for the database and test it with your functional tests as well. It will be slow, but it has to run only once, for example by every new release... If you need functional tests by developing, you can mock it out with an in memory solution again... An alternative approach to run only the affected functional tests by developing, or modify the settings of the test db to make things faster, and so on... I am sure there are many test optimization solutions...
I must say I don't really understand
your exact problem. Is the problem
that your database is left in an
altered state after you've run the
test?
Yes, there are actually two issues here. First one being the problem with the database left in an inconsistent state after running the test cases. The second one being that I'm looking for an elegant solution in terms of end-to-end testing of web services.
For efficient unit testing you should
be able to create the SUT without the
context. It sounds like you have some
hidden dependencies somewhere. That
might be the root of some of your
headache.
That indeed was the root cause of my headaches which I am now about to do away with with the help of a mocking framework.
It seems you are worried about the
database's constistency after you have
running the tests. If possible use a
own database for testing, where you
don't need care about it. If you have
such a sandbox database you can delete
data as you wish.
This is indeed one of the solutions to the problem I mentioned in my previous post but this might not work in all the cases esp when integrating with a legacy system in which the database/data isn't in your control and in cases when some DAO methods require a certain data to be already present in a given set of tables. Should I look into database unit testing frameworks like DBUnit?
In this case it pays of the
stub/fake/mock the layer talking to
the network. Or consider
https://wsunit.dev.java.net/.
Ah, looks interesting. I've also heard of tools like SOAPUI and the likes which can be used for functional testing. Has anyone here had any success with such tools?
Thanks for all the answers and apologies for the ambiguous explanation; English isn't my first language.
-sasuke

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