Add [NoDb] attribute to opt a test out of a database

pages/choosing-a-test-strategy.md

@@ -76,6 +76,7 @@ A common split:
  * Mocks or fakes for domain and business logic.
  * LocalDb for data access, queries, migrations, and end-to-end integration tests.
  * `[PooledDb]` or `[SharedDb]` for large sets of read-only tests, with a new database per test for anything that writes.
+ * `[NoDb]` for tests in a `LocalDbTestBase` class that do not touch the database, such as rendering or validation tests. This keeps them next to related database tests without paying for a database.
 
 
 ## Summary

pages/ef-mstest-usage.md

@@ -648,7 +648,7 @@ public async Task VerifyEntity_Queryable()
 
 Mark test methods with `[SharedDb]` to share a single database across all query-only tests. Instead of cloning the template for each test, a shared database is created once and reused. This eliminates per-test DB creation overhead for tests that only read data.<!-- include: shared-db. path: /pages/mdsource/shared-db.include.md -->
 
-`[SharedDb]` can also be applied to a test class, or to the assembly with `[assembly: SharedDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]` and `[NewDb]` to the same method, class, or assembly throws.
+`[SharedDb]` can also be applied to a test class, or to the assembly with `[assembly: SharedDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]`, `[NewDb]` and `[NoDb]` to the same method, class, or assembly throws.
 
 The shared database is read-only and any write throws, not only `SaveChanges`: `ExecuteUpdate`, `ExecuteDelete`, `ExecuteSqlRaw` and hand-written commands are blocked too. Tests that need to write should use `[PooledDb]` instead.<!-- endInclude -->
 
@@ -675,7 +675,7 @@ public class SharedDbTests : LocalDbTestBase<TheDbContext>
 
 Mark test methods with `[PooledDb]` to lease a database from a fixed pool instead of creating one per test. The pool is built once from the template, and each test leases a database for its duration, writes inside a transaction, and rolls that transaction back on release so the next test sees the template state again.<!-- include: pooled-db. path: /pages/mdsource/pooled-db.include.md -->
 
-`[PooledDb]` can also be applied to a test class, or to the assembly with `[assembly: PooledDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]` and `[NewDb]` to the same method, class, or assembly throws.
+`[PooledDb]` can also be applied to a test class, or to the assembly with `[assembly: PooledDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]`, `[NewDb]` and `[NoDb]` to the same method, class, or assembly throws.
 
 Two costs disappear. The per-test file copy and attach is gone, and — usually the larger one — so is repeated query plan compilation: SQL Server keys the plan cache by database, so a database per test means every query is compiled afresh for every test and no plan is ever reused. A small pool lets those plans be reused for the rest of the run.
 
@@ -759,6 +759,17 @@ public class PooledDbTests : LocalDbTestBase<TheDbContext>
 <!-- endSnippet -->
 
 
+## NoDb
+
+Mark a test method with `[NoDb]` when it does not touch the database, for example a test that renders a document, formats output, or runs a validator. The test still inherits from `LocalDbTestBase`, so it can live next to related database tests, but no database is built for it.<!-- include: no-db. path: /pages/mdsource/no-db.include.md -->
+
+A test without any attribute gets a new database per test, which is the most expensive mode. So a database-free test in a `LocalDbTestBase` class should be marked `[NoDb]` rather than left unmarked.
+
+In a `[NoDb]` test `Database` is null, and accessing `ArrangeData`, `ActData`, or `AssertData`, or calling `Reset`, throws.
+
+`[NoDb]` can also be applied to a test class. The nearest attribute wins, so a method marked `[PooledDb]`, `[SharedDb]`, or `[NewDb]` in a `[NoDb]` class gets a database. Applying `[NoDb]` together with `[PooledDb]`, `[SharedDb]` or `[NewDb]` to the same method or class throws.<!-- endInclude -->
+
+
 ## Parallel Execution
 
 To run tests in parallel, configure parallelism at the assembly level:

pages/ef-nunit-usage.md

@@ -657,7 +657,7 @@ public async Task VerifyEntity_Queryable()
 
 Mark test methods with `[SharedDb]` to share a single database across all query-only tests. Instead of cloning the template for each test, a shared database is created once and reused. This eliminates per-test DB creation overhead for tests that only read data.<!-- include: shared-db. path: /pages/mdsource/shared-db.include.md -->
 
-`[SharedDb]` can also be applied to a test class, or to the assembly with `[assembly: SharedDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]` and `[NewDb]` to the same method, class, or assembly throws.
+`[SharedDb]` can also be applied to a test class, or to the assembly with `[assembly: SharedDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]`, `[NewDb]` and `[NoDb]` to the same method, class, or assembly throws.
 
 The shared database is read-only and any write throws, not only `SaveChanges`: `ExecuteUpdate`, `ExecuteDelete`, `ExecuteSqlRaw` and hand-written commands are blocked too. Tests that need to write should use `[PooledDb]` instead.<!-- endInclude -->
 
@@ -685,7 +685,7 @@ public class SharedDbTests :
 
 Mark test methods with `[PooledDb]` to lease a database from a fixed pool instead of creating one per test. The pool is built once from the template, and each test leases a database for its duration, writes inside a transaction, and rolls that transaction back on release so the next test sees the template state again.<!-- include: pooled-db. path: /pages/mdsource/pooled-db.include.md -->
 
-`[PooledDb]` can also be applied to a test class, or to the assembly with `[assembly: PooledDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]` and `[NewDb]` to the same method, class, or assembly throws.
+`[PooledDb]` can also be applied to a test class, or to the assembly with `[assembly: PooledDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]`, `[NewDb]` and `[NoDb]` to the same method, class, or assembly throws.
 
 Two costs disappear. The per-test file copy and attach is gone, and — usually the larger one — so is repeated query plan compilation: SQL Server keys the plan cache by database, so a database per test means every query is compiled afresh for every test and no plan is ever reused. A small pool lets those plans be reused for the rest of the run.
 
@@ -770,6 +770,17 @@ public class PooledDbTests :
 <!-- endSnippet -->
 
 
+## NoDb
+
+Mark a test method with `[NoDb]` when it does not touch the database, for example a test that renders a document, formats output, or runs a validator. The test still inherits from `LocalDbTestBase`, so it can live next to related database tests, but no database is built for it.<!-- include: no-db. path: /pages/mdsource/no-db.include.md -->
+
+A test without any attribute gets a new database per test, which is the most expensive mode. So a database-free test in a `LocalDbTestBase` class should be marked `[NoDb]` rather than left unmarked.
+
+In a `[NoDb]` test `Database` is null, and accessing `ArrangeData`, `ActData`, or `AssertData`, or calling `Reset`, throws.
+
+`[NoDb]` can also be applied to a test class. The nearest attribute wins, so a method marked `[PooledDb]`, `[SharedDb]`, or `[NewDb]` in a `[NoDb]` class gets a database. Applying `[NoDb]` together with `[PooledDb]`, `[SharedDb]` or `[NewDb]` to the same method or class throws.<!-- endInclude -->
+
+
 ## Parallel Execution
 
 To run tests in parallel, configure parallelism at the assembly level:

pages/ef-tunit-usage.md

@@ -656,7 +656,7 @@ public async Task VerifyEntity_Queryable()
 
 Mark test methods with `[SharedDb]` to share a single database across all query-only tests. Instead of cloning the template for each test, a shared database is created once and reused. This eliminates per-test DB creation overhead for tests that only read data.<!-- include: shared-db. path: /pages/mdsource/shared-db.include.md -->
 
-`[SharedDb]` can also be applied to a test class, or to the assembly with `[assembly: SharedDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]` and `[NewDb]` to the same method, class, or assembly throws.
+`[SharedDb]` can also be applied to a test class, or to the assembly with `[assembly: SharedDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]`, `[NewDb]` and `[NoDb]` to the same method, class, or assembly throws.
 
 The shared database is read-only and any write throws, not only `SaveChanges`: `ExecuteUpdate`, `ExecuteDelete`, `ExecuteSqlRaw` and hand-written commands are blocked too. Tests that need to write should use `[PooledDb]` instead.<!-- endInclude -->
 
@@ -682,7 +682,7 @@ public class SharedDbTests : LocalDbTestBase<TheDbContext>
 
 Mark test methods with `[PooledDb]` to lease a database from a fixed pool instead of creating one per test. The pool is built once from the template, and each test leases a database for its duration, writes inside a transaction, and rolls that transaction back on release so the next test sees the template state again.<!-- include: pooled-db. path: /pages/mdsource/pooled-db.include.md -->
 
-`[PooledDb]` can also be applied to a test class, or to the assembly with `[assembly: PooledDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]` and `[NewDb]` to the same method, class, or assembly throws.
+`[PooledDb]` can also be applied to a test class, or to the assembly with `[assembly: PooledDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]`, `[NewDb]` and `[NoDb]` to the same method, class, or assembly throws.
 
 Two costs disappear. The per-test file copy and attach is gone, and — usually the larger one — so is repeated query plan compilation: SQL Server keys the plan cache by database, so a database per test means every query is compiled afresh for every test and no plan is ever reused. A small pool lets those plans be reused for the rest of the run.
 
@@ -766,6 +766,17 @@ public class PooledDbTests : LocalDbTestBase<TheDbContext>
 <!-- endSnippet -->
 
 
+## NoDb
+
+Mark a test method with `[NoDb]` when it does not touch the database, for example a test that renders a document, formats output, or runs a validator. The test still inherits from `LocalDbTestBase`, so it can live next to related database tests, but no database is built for it.<!-- include: no-db. path: /pages/mdsource/no-db.include.md -->
+
+A test without any attribute gets a new database per test, which is the most expensive mode. So a database-free test in a `LocalDbTestBase` class should be marked `[NoDb]` rather than left unmarked.
+
+In a `[NoDb]` test `Database` is null, and accessing `ArrangeData`, `ActData`, or `AssertData`, or calling `Reset`, throws.
+
+`[NoDb]` can also be applied to a test class. The nearest attribute wins, so a method marked `[PooledDb]`, `[SharedDb]`, or `[NewDb]` in a `[NoDb]` class gets a database. Applying `[NoDb]` together with `[PooledDb]`, `[SharedDb]` or `[NewDb]` to the same method or class throws.<!-- endInclude -->
+
+
 ## Parallel Execution
 
 To run tests in parallel, configure parallelism at the assembly level:

pages/ef-xunitv3-usage.md

@@ -655,7 +655,7 @@ public async Task VerifyEntity_Queryable()
 
 Mark test methods with `[SharedDb]` to share a single database across all query-only tests. Instead of cloning the template for each test, a shared database is created once and reused. This eliminates per-test DB creation overhead for tests that only read data.<!-- include: shared-db. path: /pages/mdsource/shared-db.include.md -->
 
-`[SharedDb]` can also be applied to a test class, or to the assembly with `[assembly: SharedDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]` and `[NewDb]` to the same method, class, or assembly throws.
+`[SharedDb]` can also be applied to a test class, or to the assembly with `[assembly: SharedDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]`, `[NewDb]` and `[NoDb]` to the same method, class, or assembly throws.
 
 The shared database is read-only and any write throws, not only `SaveChanges`: `ExecuteUpdate`, `ExecuteDelete`, `ExecuteSqlRaw` and hand-written commands are blocked too. Tests that need to write should use `[PooledDb]` instead.<!-- endInclude -->
 
@@ -681,7 +681,7 @@ public class SharedDbTests : LocalDbTestBase<TheDbContext>
 
 Mark test methods with `[PooledDb]` to lease a database from a fixed pool instead of creating one per test. The pool is built once from the template, and each test leases a database for its duration, writes inside a transaction, and rolls that transaction back on release so the next test sees the template state again.<!-- include: pooled-db. path: /pages/mdsource/pooled-db.include.md -->
 
-`[PooledDb]` can also be applied to a test class, or to the assembly with `[assembly: PooledDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]` and `[NewDb]` to the same method, class, or assembly throws.
+`[PooledDb]` can also be applied to a test class, or to the assembly with `[assembly: PooledDb]`. The nearest attribute wins: a method attribute overrides a class attribute, which overrides an assembly attribute. Mark a test method or class with `[NewDb]` to opt it out and create a database per test. Applying more than one of `[PooledDb]`, `[SharedDb]`, `[NewDb]` and `[NoDb]` to the same method, class, or assembly throws.
 
 Two costs disappear. The per-test file copy and attach is gone, and — usually the larger one — so is repeated query plan compilation: SQL Server keys the plan cache by database, so a database per test means every query is compiled afresh for every test and no plan is ever reused. A small pool lets those plans be reused for the rest of the run.
 
@@ -764,6 +764,17 @@ public class PooledDbTests : LocalDbTestBase<TheDbContext>
 <!-- endSnippet -->
 
 
+## NoDb
+
+Mark a test method with `[NoDb]` when it does not touch the database, for example a test that renders a document, formats output, or runs a validator. The test still inherits from `LocalDbTestBase`, so it can live next to related database tests, but no database is built for it.<!-- include: no-db. path: /pages/mdsource/no-db.include.md -->
+
+A test without any attribute gets a new database per test, which is the most expensive mode. So a database-free test in a `LocalDbTestBase` class should be marked `[NoDb]` rather than left unmarked.
+
+In a `[NoDb]` test `Database` is null, and accessing `ArrangeData`, `ActData`, or `AssertData`, or calling `Reset`, throws.
+
+`[NoDb]` can also be applied to a test class. The nearest attribute wins, so a method marked `[PooledDb]`, `[SharedDb]`, or `[NewDb]` in a `[NoDb]` class gets a database. Applying `[NoDb]` together with `[PooledDb]`, `[SharedDb]` or `[NewDb]` to the same method or class throws.<!-- endInclude -->
+
+
 ## Parallel Execution
 
 To run tests in parallel, configure parallelism at the assembly level:

pages/mdsource/choosing-a-test-strategy.source.md

@@ -69,6 +69,7 @@ A common split:
  * Mocks or fakes for domain and business logic.
  * LocalDb for data access, queries, migrations, and end-to-end integration tests.
  * `[PooledDb]` or `[SharedDb]` for large sets of read-only tests, with a new database per test for anything that writes.
+ * `[NoDb]` for tests in a `LocalDbTestBase` class that do not touch the database, such as rendering or validation tests. This keeps them next to related database tests without paying for a database.
 
 
 ## Summary

pages/mdsource/ef-mstest-usage.source.md

@@ -83,6 +83,11 @@ include: pooled-db
 snippet: PooledDbTestsMSTest
 
 
+## NoDb
+
+include: no-db
+
+
 ## Parallel Execution
 
 To run tests in parallel, configure parallelism at the assembly level:

pages/mdsource/ef-nunit-usage.source.md

@@ -83,6 +83,11 @@ include: pooled-db
 snippet: PooledDbTestsNUnit
 
 
+## NoDb
+
+include: no-db
+
+
 ## Parallel Execution
 
 To run tests in parallel, configure parallelism at the assembly level:

pages/mdsource/ef-tunit-usage.source.md

@@ -83,6 +83,11 @@ include: pooled-db
 snippet: PooledDbTestsTUnit
 
 
+## NoDb
+
+include: no-db
+
+
 ## Parallel Execution
 
 To run tests in parallel, configure parallelism at the assembly level:

pages/mdsource/ef-xunitv3-usage.source.md

@@ -83,6 +83,11 @@ include: pooled-db
 snippet: PooledDbTestsXunitV3
 
 
+## NoDb
+
+include: no-db
+
+
 ## Parallel Execution
 
 To run tests in parallel, configure parallelism at the assembly level:

pages/mdsource/no-db.include.md

@@ -0,0 +1,7 @@
+Mark a test method with `[NoDb]` when it does not touch the database, for example a test that renders a document, formats output, or runs a validator. The test still inherits from `LocalDbTestBase`, so it can live next to related database tests, but no database is built for it.
+
+A test without any attribute gets a new database per test, which is the most expensive mode. So a database-free test in a `LocalDbTestBase` class should be marked `[NoDb]` rather than left unmarked.
+
+In a `[NoDb]` test `Database` is null, and accessing `ArrangeData`, `ActData`, or `AssertData`, or calling `Reset`, throws.
+
+`[NoDb]` can also be applied to a test class. The nearest attribute wins, so a method marked `[PooledDb]`, `[SharedDb]`, or `[NewDb]` in a `[NoDb]` class gets a database. Applying `[NoDb]` together with `[PooledDb]`, `[SharedDb]` or `[NewDb]` to the same method or class throws.