db-pool

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A thread-safe database pool for running database-tied integration tests in parallel with:

• Easy setup
• Proper isolation
• Automatic creation, reuse, and cleanup
• Async support

Description

Rather than simply providing a database connection pool that allows multiple connections to the same database, db-pool maintains a pool of separate isolated databases in order to allow running database-tied tests in parallel. It also handles the lifecycles of those databases: whenever you pick a database out of the pool, you can be sure that the database is clean and ready to be used, and that no other tests are connected to the database you are using in any one test.

Motivation

When running tests against a database-tied service, such as a web server, a test database is generally used. However, this comes with its own set of difficulties:

1. The database has to be either (a) dropped and re-created or (b) cleaned before every test.
2. Tests have to run serially in order to avoid cross-contamination.

This leads to several issues when running tests serially:

• Test setup and teardown is now required.
• Dropping and creating a database from scratch can be expensive.
• Cleaning a database instead of dropping and re-creating one requires careful execution of dialect-specific statements.

When switching to parallel execution of tests, even more difficulties arise:

• Creating and dropping a database for each test can be expensive.
• Sharing temporary databases across tests requires:
  • isolating databases in concurrent use
  • cleaning each database before reuse by a subsequent test
  • restricting user privileges to prevent schema modification by rogue tests
  • dropping temporary databases before or after a test run to reduce clutter

db-pool takes care of all of these concerns while supporting multiple database types, backends, and connection pools.

Databases

• MySQL (MariaDB)
• PostgreSQL

Backends & Pools

Sync

Backend	Pool	Feature
diesel/mysql	r2d2	diesel-mysql
diesel/postgres	r2d2	diesel-postgres
mysql	r2d2	mysql
postgres	r2d2	postgres

Async

Backend	Pool	Features
diesel-async/mysql	bb8	diesel-async-mysql, diesel-async-bb8
diesel-async/mysql	mobc	diesel-async-mysql, diesel-async-mobc
diesel-async/postgres	bb8	diesel-async-postgres, diesel-async-bb8
diesel-async/postgres	mobc	diesel-async-postgres, diesel-async-mobc
sea-orm/sqlx-mysql	sqlx	sea-orm-mysql
sea-orm/sqlx-postgres	sqlx	sea-orm-postgres
sqlx/mysql	sqlx	sqlx-mysql
sqlx/postgres	sqlx	sqlx-postgres
tokio-postgres	bb8	tokio-postgres, tokio-postgres-bb8
tokio-postgres	mobc	tokio-postgres, tokio-postgres-mobc