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<TContext>

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 EFTESTREWRITE_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 EFTESTREWRITE_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

Running Tests Directly Against the Built Assembly

When invoking the test DLL via dotnet exec (e.g. to isolate a single test method without rebuilding through dotnet test), always append --filter-not-trait category=failing --ignore-exit-code 8:

dotnet exec ./Microsoft.EntityFrameworkCore.SqlServer.FunctionalTests.dll `
    --filter-method '*MigrationsSqlServerTest.Create_json_index_over_whole_complex_collection' `
    --filter-not-trait category=failing --ignore-exit-code 8

These flags mirror what test/Directory.Build.props passes via TestingPlatformCommandLineArguments.

Don't add --no-build unless the test assembly was built in the immediate previous step.