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What is isolated unit testing?
A unit test is a way of testing a unit – the smallest piece of code that can be logically isolated in a system. In most programming languages, that is a function, a subroutine, a method or property. The isolated part of the definition is important.
What is in-memory database testing?
An in-memory database is a database that runs entirely in main memory, without touching a disk. Often they run as an embedded database: created when a process starts, running embedded within that process, and is destroyed when the process finishes.
Should unit tests hit the database?
Unit tests should not hit the database. They should test that the methods run as expected if the right data is available (regardless of where that data comes from). Therefore you should be stubbing/mocking as necessary to ensure that each unit test is isolated.
Should you unit test data Access Layer?
It is a good practice to write unit test for every layer, even the DAL. I don’t think running tests on the real db is a good idea, you might ruin important data. We used to set up a copy of the db for tests with just enough data in it to run tests on.
Why tests should be isolated?
Because an isolated test must set up all collaborators as mocks, the only way to reduce the mock complexity is to reduce the depth of collaboration. If we mock three levels deep, and do nothing to reduce that mock depth, then we’re spending the effort to isolate without getting the benefit.
What is meant by in-memory database?
An in-memory database is a type of purpose-built database that relies primarily on memory for data storage, in contrast to databases that store data on disk or SSDs. In-memory databases can persist data on disks by storing each operation in a log or by taking snapshots.
Is mysql in-memory database?
It does not qualify it as in in-memory database. There are other systems that also offer in-memory options; like SQLite. An example of an in-memory database is voltdb. redis is sometimes referred to as an in-memory database, but strictly speaking, its a key/value store.
What are the different types of integration testing?
Some different types of integration testing are big-bang, mixed (sandwich), risky-hardest, top-down, and bottom-up. Other Integration Patterns are: collaboration integration, backbone integration, layer integration, client-server integration, distributed services integration and high-frequency integration.
When to use in memory database in unit tests?
Fast: Creating new in-memory database for each test should not impose performance penalty onto tests if there not too many tables and constraints. Isolated: Separate databases are used for each test, means no shared resource is being used, which helps isolation.
Can you write integration tests against an in memory database?
First and foremost, an in-memory provider is a pale imitation for the real thing. Even with writing in-memory tests, we still absolutely wrote integration tests against a real database. Those unit tests with in-memory looked exactly like the integration tests, just with a different provider.
What are the benefits of isolated unit tests?
Isolated: Each test is self-contained and does not rely on any other data. They can be run in any order. Repeatable: The test runs must be repeated over and over again. In each and every run they should either pass every time or always fail. Self-validating: There is no need for human interpretation whether or not the test succeeded or failed.
How many instances of dbcontext do I need for unit test?
Note: In some of my unit tests I need to use three instances of the DbContext to correctly test something. One for seeding the database, one for running the test, and a final one to verify that the database has been written correctly. It’s likely that the actual database you use isn’t going to be SQLite.