testing

name	testing
description	Implementation details for EF Core test infrastructure. Use when changing test fixtures, SQL baseline assertions, test helpers, the test class hierarchy, or when adding new tests.
user-invocable	false

Testing

Test Categories

Unit Tests (test/EFCore.Tests/, test/EFCore.Relational.Tests/, test/EFCore.{Provider}.Tests/)

Isolated logic tests. Build models via *TestHelpers.Instance.CreateConventionBuilder(), resolve services from CreateContextServices(). No database needed.

Specification Tests (provider-agnostic abstract bases)

Define WHAT to test (LINQ queries, expected results). Can't be run directly — provider tests override to verify HOW (generated SQL).

• Core → test/EFCore.Specification.Tests/
• Relational → test/EFCore.Relational.Specification.Tests/

Functional Tests (test/EFCore.{Provider}.FunctionalTests/)

Concrete provider tests inheriting specification tests. Most include SQL baseline assertions.

Test Class Hierarchy (Query Example)

QueryTestBase<TFixture>                                    # Core
  └─ NorthwindWhereQueryTestBase<TFixture>                 # Specification
      └─ NorthwindWhereQueryRelationalTestBase<TFixture>   # Relational specification
          └─ NorthwindWhereQuerySqlServerTest              # Provider (asserts SQL)

Provider override pattern:

public override async Task Where_simple(bool async)
{
    await base.Where_simple(async);  // runs LINQ + asserts results
    AssertSql("""...""");            // asserts provider-specific SQL
}

TestHelpers Hierarchy

TestHelpers (abstract)                  # EFCore.Specification.Tests
  ├─ InMemoryTestHelpers               # non-relational
  └─ RelationalTestHelpers (abstract)  # EFCore.Relational.Specification.Tests
      ├─ SqlServerTestHelpers
      └─ SqliteTestHelpers

Key methods: CreateConventionBuilder(), CreateContextServices(model), CreateOptions()

Fixtures

SharedStoreFixtureBase

Many tests share one database. Creates TestStore + pooled DbContextFactory in InitializeAsync(). Seeds data once. Use for read-heavy tests (e.g., Northwind query tests).

NonSharedModelTestBase

Each test gets a fresh model/store. Call InitializeAsync<TContext>(onModelCreating, seed, ...) per test. Use for tests needing unique schemas.

SQL Baseline Assertions

TestSqlLoggerFactory captures SQL. AssertSql("""...""") compares against expected. Set EF_TEST_REWRITE_BASELINES=1 to auto-rewrite baselines via Roslyn.

Workflow: Adding New Tests

1. Specification test: Add to EFCore.Specification.Tests (core) or EFCore.Relational.Specification.Tests (relational)
2. Provider overrides: Override in every provider functional test class (EFCore.{Provider}.FunctionalTests) that inherits the base with provider-appropriate assertions.
3. Unit test: Add to EFCore.{Provider}.Tests
4. Run with EF_TEST_REWRITE_BASELINES=1 to capture initial baselines
5. Run tests with project rebuilding enabled (don't use --no-build) to ensure code changes are picked up
6. When testing cross-platform code (e.g., file paths, path separators), verify the fix works on both Windows and Linux/macOS

Common Pitfalls

Pitfall	Solution
Baseline mismatch (SQL or compiled model)	Re-run with EF_TEST_REWRITE_BASELINES=1
Check_all_tests_overridden fails	Override the new test in every inheriting provider class
SQL Server feature missing at lower compat level	Gate with [SqlServerCondition(...)]