I'm currently building a rest api and I'm struggling to find the best way to unit test each route.
A route handler performs various things and one of them is to execute a query to mongodb. I can unit test the route handler by using stubs, but if I'm testing the query I cannot stub the query itself, I need to have an in-memory mongodb that I could reset and insert new data for each test.
How do you test queries? I'm thinking that the only real way to ensure that the query does what I need is to use a real mongodb database installed in the testing machine (typically in the same machine used for developing).
yes, just as for relation databases, you need to have real base. if mongo offers in-memory auto-created version then it's easy. if not, then each developer has to have running mongo before he runs integration tests. for CI you can have one single dedicated mongo but than you have to prevent concurrent access (schema creation, multiple transactions etc). you should also implement automatic creation of schema if needed and empty database before each test. in relational db rollback is usually enough. when it's not enough then trimming all tables helps. although we had to implement it manually as we couldn't find any existing tools
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I have a database (PostgreSQL) in development environment, which allows me to develop a GraphQL api in NodeJS. I would like to know how to do when I make modifications to the database, pass these modifications to staging and then to production automatically, without having to redo all the queries and so on in each environment.
Do you know how to do it?
Thank you
A typical solution is to use something like migrations. You should have a special table that stores an information about all applied migrations.
The first migration can just execute an initial script that creates all tables, relations, functions and so on.
The subsequent migrations modify structure according to changes in your app and you always know what migrations was applied to a certain DB.
To achieve working with migration you should find a suitable package that can create, execute and undo migrations and maybe seeders as well (something like this package).
I am working on a nodejs application. The database used is cassandra. We are using https://www.npmjs.com/package/dse-driver.
I am trying to understand how to write tests for the application.
I am specifically confused about how to keep my test database separate from development database.
Can we create and destroy test databases on the fly like Django?
How are test cases for cassandra and nodejs written?
What are the best practices for the same?
You can create a testkeyspace where you initially set up all the tables before each test and drop it afterwards.
If you do so, you should keep in mind, that after truncating tables, there are still snapshots on the filesystem. You probably would want to setup a cleanup job.
Here is my situation. I have an extensive REST based API that connects to a MongoDB database using Mongoose. The API is written as a standard "MEAN" stack application.
Currently, when a developer queries the API they're always connecting to the live production database. What I want to do is have an exact duplicate database as a "staging" database, where new data will be added first, vetted over a period of time, and then move to the live database. Then I want developers to be able to query either one simply by modifying their query.
I started looking into this with the Mongoose documentation, and it appears as though the models are tied to the DB connection, and if I want to have multiple connections I also have to have multiple models, one for each connection. This would be a nightmare of WET code and not the path I want to take.
What I want to do is not touch any of my code at all and simply have a switch that changes to the proper database for a given query. So my question is, how can I achieve this? Is it possible? The documentation seems to imply it is not.
Rather than trying to maintain connections two environments in the same code base have you considered setting up stage version of your application? Which database it connects to could be set through an environment variable or some other configuration option.
The developers would still then only have to make a change to query one or the other and you could migrate data from the stage database to production/live database once you have finished your vetting process.
I have an api written in node with a mongodb back end.
I'm using supertest to automate testing of an api. Of course this results in a lot of changes to database and I like to get some input on options for managing this. The goal is for each test to have no permanent impact on the database. The database should look exactly the same after the test is finished as it did before the test ran.
In my case, I don't want the database to be dropped or fully emptied out between tests. I need some real data maintained in the database at all times. I just want the changes by the tests themselves to be reverted.
With a relational database, I would put a transaction around each unit tests and roll it back after the test was done (pass or fail). As far as I know, this is not an option with mongo.
Some options I have considered:
Fake databases
I've heard of in-memory databases like fongo (which is a Java thing) and tingodb. I haven't used these but the issue with this type of solution is always that it requires a good parity with the actual product to maintain itself as a viable option. As soon as I used a mongo feature that the fake doesn't support I'll have a problem unit testing.
Manual cleanup
There is always the option of just having a routine that finds all the data added by the test (marked in some way) and removes it. You'd have to be careful about updates and deletes here. Also there is likely a lot of upkeep making sure the cleanup routine accurately cleans things up.
Database copying
If it were fast enough, maybe having a baseline test database and making a copy of it before each test could work. It'd have to be pretty fast though.
So how do people generally handle this?
I think this is a brand new way in testing without transaction.
imho - using mongo >=3.2, we can setup inMemory storage engine, which is perfect for this kind of scenario.
Start mongo with inMemory
restore database
create a working copy for test
perform a test on working copy
drop working copy
if more tests GOTO 3
I have NodeJS app that uses MongoDB as database. I'm using native mongo driver (not mongoess).
The application allow users to work on projects and share them and the logic that decide which projects a user is allowed to see is built as mongo criteria selector.
In order to test that I've found TingoDB which looks like a great candidate for mocking the MongoDB to be able to run the real model code and check that it is working.
My question is what is the best way to load the initial data? keep it in separate file? Keep it as another model?
Thank you,
Ido.
TingoDB actually stores it's data in flat-files, so if you want, you could just keep a copy of the database in a directory and load that.
However, if you're just testing with a small amount of data, you'd probably be better off keeping the test-data as in your testing scripts, and inserting it through your application as part of the test. That way, you can easily compare the data in the application to the data you loaded in your assertions.
Finally, if you're running MongoDB in production, then you should probably use MongoDB in your tests. While they do have nearly identical APIs, they have very different performance, which should be something you're keeping track of in testing. Unless there's a need to use TingoDB during testing, I'd try to make it as similar to the production environment as possible.