Return null from ArrangeData in [NoDb] tests

pages/ef-mstest-usage.md

@@ -767,7 +767,7 @@ Mark a test method with `[NoDb]` when it does not touch the database, for exampl
 
 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.
+In a `[NoDb]` test `Database` and `ArrangeData` are null, so code under test that takes a context it never uses can still be constructed with `ArrangeData`. Accessing `ActData` or `AssertData`, or calling `Reset`, throws.
 
 In a database test, recording resumes on the first access of `ActData`. A `[NoDb]` test has no `ActData`, so recording is resumed when the test starts. Other recorded activity, such as NServiceBus messages sent by the code under test, still appears in the snapshot.
 

pages/ef-nunit-usage.md

@@ -778,7 +778,7 @@ Mark a test method with `[NoDb]` when it does not touch the database, for exampl
 
 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.
+In a `[NoDb]` test `Database` and `ArrangeData` are null, so code under test that takes a context it never uses can still be constructed with `ArrangeData`. Accessing `ActData` or `AssertData`, or calling `Reset`, throws.
 
 In a database test, recording resumes on the first access of `ActData`. A `[NoDb]` test has no `ActData`, so recording is resumed when the test starts. Other recorded activity, such as NServiceBus messages sent by the code under test, still appears in the snapshot.
 

pages/ef-tunit-usage.md

@@ -774,7 +774,7 @@ Mark a test method with `[NoDb]` when it does not touch the database, for exampl
 
 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.
+In a `[NoDb]` test `Database` and `ArrangeData` are null, so code under test that takes a context it never uses can still be constructed with `ArrangeData`. Accessing `ActData` or `AssertData`, or calling `Reset`, throws.
 
 In a database test, recording resumes on the first access of `ActData`. A `[NoDb]` test has no `ActData`, so recording is resumed when the test starts. Other recorded activity, such as NServiceBus messages sent by the code under test, still appears in the snapshot.
 

pages/ef-xunitv3-usage.md

@@ -772,7 +772,7 @@ Mark a test method with `[NoDb]` when it does not touch the database, for exampl
 
 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.
+In a `[NoDb]` test `Database` and `ArrangeData` are null, so code under test that takes a context it never uses can still be constructed with `ArrangeData`. Accessing `ActData` or `AssertData`, or calling `Reset`, throws.
 
 In a database test, recording resumes on the first access of `ActData`. A `[NoDb]` test has no `ActData`, so recording is resumed when the test starts. Other recorded activity, such as NServiceBus messages sent by the code under test, still appears in the snapshot.
 

pages/mdsource/no-db.include.md

@@ -2,7 +2,7 @@ Mark a test method with `[NoDb]` when it does not touch the database, for exampl
 
 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.
+In a `[NoDb]` test `Database` and `ArrangeData` are null, so code under test that takes a context it never uses can still be constructed with `ArrangeData`. Accessing `ActData` or `AssertData`, or calling `Reset`, throws.
 
 In a database test, recording resumes on the first access of `ActData`. A `[NoDb]` test has no `ActData`, so recording is resumed when the test starts. Other recorded activity, such as NServiceBus messages sent by the code under test, still appears in the snapshot.
 

src/EfLocalDb.MSTest.Tests/NoDbTests.cs

@@ -8,9 +8,14 @@ public void HasNoDatabase() =>
 
     [TestMethod]
     [NoDb]
-    public void ArrangeDataThrows()
+    public void ArrangeDataIsNull() =>
+        Assert.IsNull(ArrangeData);
+
+    [TestMethod]
+    [NoDb]
+    public void ActDataThrows()
     {
-        var exception = Assert.ThrowsExactly<Exception>(() => _ = ArrangeData);
+        var exception = Assert.ThrowsExactly<Exception>(() => _ = ActData);
         Assert.Contains("[NoDb]", exception.Message);
     }
 

src/EfLocalDb.MSTest/LocalDbTestBase.cs

@@ -154,15 +154,21 @@ void ThrowIfNoDb()
     {
         if (isNoDb)
         {
-            throw new("The test is marked [NoDb], so it has no database. Remove [NoDb] to use ArrangeData, ActData, AssertData, or Reset.");
+            throw new("The test is marked [NoDb], so it has no database. Remove [NoDb] to use ActData, AssertData, or Reset.");
         }
     }
 
     public virtual T ArrangeData
     {
         get
         {
-            ThrowIfNoDb();
+            // Code under test often takes a context it never uses in a [NoDb] test,
+            // so return null rather than throw
+            if (isNoDb)
+            {
+                return null!;
+            }
+
             if (phase == Phase.Act)
             {
                 throw new("Phase has already moved to Act. Check for a ActData usage in the preceding code.");

src/EfLocalDb.NUnit.Tests/NoDbTests.cs

@@ -9,9 +9,14 @@ public void HasNoDatabase() =>
 
     [Test]
     [NoDb]
-    public void ArrangeDataThrows()
+    public void ArrangeDataIsNull() =>
+        IsNull(ArrangeData);
+
+    [Test]
+    [NoDb]
+    public void ActDataThrows()
     {
-        var exception = Throws<Exception>(() => _ = ArrangeData)!;
+        var exception = Throws<Exception>(() => _ = ActData)!;
         That(exception.Message, Does.Contain("[NoDb]"));
     }
 

src/EfLocalDb.NUnit/LocalDbTestBase.cs

@@ -156,15 +156,21 @@ void ThrowIfNoDb()
     {
         if (isNoDb)
         {
-            throw new("The test is marked [NoDb], so it has no database. Remove [NoDb] to use ArrangeData, ActData, AssertData, or Reset.");
+            throw new("The test is marked [NoDb], so it has no database. Remove [NoDb] to use ActData, AssertData, or Reset.");
         }
     }
 
     public virtual T ArrangeData
     {
         get
         {
-            ThrowIfNoDb();
+            // Code under test often takes a context it never uses in a [NoDb] test,
+            // so return null rather than throw
+            if (isNoDb)
+            {
+                return null!;
+            }
+
             if (phase == Phase.Act)
             {
                 throw new("Phase has already moved to Act. Check for a ActData usage in the preceding code.");

src/EfLocalDb.TUnit.Tests/NoDbTests.cs

@@ -7,9 +7,14 @@ public async Task HasNoDatabase() =>
 
     [Test]
     [NoDb]
-    public async Task ArrangeDataThrows()
+    public async Task ArrangeDataIsNull() =>
+        await Assert.That(ArrangeData).IsNull();
+
+    [Test]
+    [NoDb]
+    public async Task ActDataThrows()
     {
-        var exception = await Assert.That(() => _ = ArrangeData).Throws<Exception>();
+        var exception = await Assert.That(() => _ = ActData).Throws<Exception>();
         await Assert.That(exception!.Message).Contains("[NoDb]");
     }
 

src/EfLocalDb.TUnit/LocalDbTestBase.cs

@@ -163,15 +163,21 @@ void ThrowIfNoDb()
     {
         if (isNoDb)
         {
-            throw new("The test is marked [NoDb], so it has no database. Remove [NoDb] to use ArrangeData, ActData, AssertData, or Reset.");
+            throw new("The test is marked [NoDb], so it has no database. Remove [NoDb] to use ActData, AssertData, or Reset.");
         }
     }
 
     public virtual T ArrangeData
     {
         get
         {
-            ThrowIfNoDb();
+            // Code under test often takes a context it never uses in a [NoDb] test,
+            // so return null rather than throw
+            if (isNoDb)
+            {
+                return null!;
+            }
+
             if (phase == Phase.Act)
             {
                 throw new("Phase has already moved to Act. Check for a ActData usage in the preceding code.");

src/EfLocalDb.Xunit.V3.Tests/NoDbTests.cs

@@ -7,9 +7,14 @@ public void HasNoDatabase() =>
 
     [Fact]
     [NoDb]
-    public void ArrangeDataThrows()
+    public void ArrangeDataIsNull() =>
+        Assert.Null(ArrangeData);
+
+    [Fact]
+    [NoDb]
+    public void ActDataThrows()
     {
-        var exception = Assert.Throws<Exception>(() => _ = ArrangeData);
+        var exception = Assert.Throws<Exception>(() => _ = ActData);
         Assert.Contains("[NoDb]", exception.Message);
     }
 

src/EfLocalDb.Xunit.V3/LocalDbTestBase.cs

@@ -158,15 +158,21 @@ void ThrowIfNoDb()
     {
         if (isNoDb)
         {
-            throw new("The test is marked [NoDb], so it has no database. Remove [NoDb] to use ArrangeData, ActData, AssertData, or Reset.");
+            throw new("The test is marked [NoDb], so it has no database. Remove [NoDb] to use ActData, AssertData, or Reset.");
         }
     }
 
     public virtual T ArrangeData
     {
         get
         {
-            ThrowIfNoDb();
+            // Code under test often takes a context it never uses in a [NoDb] test,
+            // so return null rather than throw
+            if (isNoDb)
+            {
+                return null!;
+            }
+
             if (phase == Phase.Act)
             {
                 throw new("Phase has already moved to Act. Check for a ActData usage in the preceding code.");