Testing

EF Core test infrastructure, patterns, and workflows for unit, specification, and functional tests.

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

Specification test: Add to EFCore.Specification.Tests (core) or EFCore.Relational.Specification.Tests (relational)
Provider override: Override in EFCore.{Provider}.FunctionalTests with AssertSql()
Unit test: Add to EFCore.{Provider}.Tests
Run with EF_TEST_REWRITE_BASELINES=1 to capture initial baselines
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
SQL or Compiled model baseline mismatch	Set `EF_TEST_REWRITE_BASELINES=1` and re-run
`Check_all_tests_overridden` fails	Override new base test in provider test class

testing