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Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Usually, no—not as a stand-in for your production database. EF Core’s UseInMemoryDatabase provider is not relational and can miss or misrepresent database behavior your application depends on. Microsoft describes it as highly limited and discourages it for most application testing, while allowing that it can suit limited, basic cases. For isolated tests needing relational behavior, use SQLite in-memory; for provider-specific behavior, test against the production database.
Why is EF Core InMemory discouraged for most ASP.NET tests?
The InMemory provider stores data through EF Core but does not reproduce a relational database. Microsoft warns that “The in-memory provider will not behave like your real database in many important ways.” That matters whenever a test is meant to establish that an application’s database behavior will work in production.
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- It does not validate relational behavior. Constraints and other relational semantics are not faithfully exercised.
- Transactions and raw SQL are unsupported. A test using the provider cannot establish that those operations work as they do on a real database.
- Queries can behave differently. For example, string comparisons may have different case-sensitivity behavior from the production provider.
As a result, a test may pass with InMemory while the corresponding operation fails or returns different results against the real database. Use it only when the test has a narrow purpose that does not depend on relational or production-provider behavior.
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What should you use instead of UseInMemoryDatabase?
SQLite in-memory for fast relational tests
SQLite provides relational behavior and is generally a more compatible local substitute than EF Core InMemory. Microsoft recommends SQLite for in-memory testing in its ASP.NET Core integration-testing guidance. It can be useful for exercising application persistence paths without connecting to a separately managed database.
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SQLite is still a different database system, not a drop-in replica of SQL Server, PostgreSQL, or another production provider. For example, SQL Server string comparisons are case-insensitive by default, whereas SQLite is case-sensitive. SQLite tests can therefore pass when production fails, or fail when production would pass.
The production provider for provider-specific behavior
When correctness depends on the production database’s SQL, functions, transactions, collation, or other provider-specific behavior, run tests against that provider and a dedicated test database. This is the direct way to check behavior against the database the application actually uses.
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Repository abstractions only when they fit the design
A repository layer can make some application logic easier to test without a database, but it changes the architecture and adds implementation and maintenance work. Treat it as a deliberate design choice, not a setting that makes a database test double equivalent to the production provider.
Do these 3 things before closing this tab:
1Fix the driver behind crashes, sound loss and screen glitches2Clear out junk files and repair common Windows errors3Scan for outdated or missing drivers - takes under a minuteHow do you keep a SQLite in-memory database available for a test?
SQLite creates its in-memory database when a low-level connection opens and deletes it when that connection closes. Keep that connection open for the lifetime of the test database; otherwise, ordinary DbContext connection handling can close it and a later operation may see a fresh, empty database.
In an ASP.NET Core integration test, replace the application’s registered DbContext service in the test host. The test host’s builder.ConfigureServices runs after the application’s Program.cs registrations, so the test can substitute SQLite for isolated relational testing or configure the production provider for a dedicated test database.
Should every integration test use the production database?
No. Use a mix that matches what each test needs to prove. Unit tests can cover isolated method logic; a focused set of integration tests can cover important request and persistence paths; and production-provider tests can target behavior that depends on the real database. Integration tests cost more to run, so broad coverage of every data permutation is not necessary to verify core infrastructure paths.
For database-backed infrastructure, representative read, write, update, and delete cases are a practical focused set. Add production-provider coverage for queries, transactions, raw SQL, or provider-specific functions when those are part of the application’s behavior. SQLite tests alone do not guarantee identical results on the production provider.
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