Add documentation for TestFixtureSource TypeArgs and move examples into snippets (#1121)

* Add documenation for testfituresource typeargs and move examples into snippets

* Update docs/articles/nunit/writing-tests/attributes/testfixturesource.md

Author: stevenaw

docs/articles/nunit/writing-tests/attributes/testfixturesource.md

@@ -11,20 +11,7 @@ its data using one of the forms of **TestFixtureSourceAttribute**:
 
 ### Form 1 - [TestFixtureSource(string sourceName)]
 
-```csharp
-[TestFixtureSource(nameof(FixtureArgs))]
-public class MyTestClass
-{
-    public MyTestClass(string word, int num) { ... }
-
-    /* ... */
-
-    static object [] FixtureArgs = {
-        new object[] { "Question", 1 },
-        new object[] { "Answer", 42 }
-    };
-}
-```
+[!code-csharp[BasicTestFixtureSource](~/snippets/Snippets.NUnit/Attributes/TestFixtureSourceAttributeExamples.cs#StaticPropertyInOwnClass)]
 
 The single attribute argument in this form is a string representing the name of the source used to provide arguments for
 constructing the `TestFixture`. It has the following characteristics:
@@ -40,23 +27,7 @@ constructing the `TestFixture`. It has the following characteristics:
 
 ### Form 2 - [TestFixtureSource(Type sourceType, string sourceName)]
 
-```csharp
-[TestFixtureSource(typeof(AnotherClass), nameof(AnotherClass.FixtureArgs)]
-public class MyTestClass
-{
-    public MyTestClass(string word, int num) { ... }
-
-    ...
-}
-
-class AnotherClass
-{
-    static object [] FixtureArgs = {
-        new object[] { "Question", 1 },
-        new object[] { "Answer", 42 }
-    };
-}
-```
+[!code-csharp[StaticPropertyInAnotherClass](~/snippets/Snippets.NUnit/Attributes/TestFixtureSourceAttributeExamples.cs#StaticPropertyInAnotherClass)]
 
 The first argument of the attribute in this form is a Type representing the class that will provide the test fixture
 data.
@@ -75,42 +46,26 @@ characteristics:
 
 ### Form 3 - [TestFixtureSource(Type sourceType)]
 
-```csharp
-[TestFixtureSource(typeof(FixtureArgs))]
-public class MyTestClass
-{
-    public MyTestClass(string word, int num) { /* ... */ }
-
-    /* ... */
-}
-
-class FixtureArgs: IEnumerable
-{
-    public IEnumerator GetEnumerator()
-    {
-        yield return new object[] { "Question", 1 };
-        yield return new object[] { "Answer", 42 };
-    }
-}
-```
-
-The Type argument in this form represents the class that provides test cases. It must have a default constructor and
+[!code-csharp[SourceFromEnumerable](~/snippets/Snippets.NUnit/Attributes/TestFixtureSourceAttributeExamples.cs#SourceFromEnumerable)]
+
+The Type argument in this form represents the class that provides test fixtures. It must have a default constructor and
 implement `IEnumerable`.
 
 The individual items returned by the enumerator must either be object arrays or derive from the `TestFixtureParameters`
 class. Arguments must be consistent with the fixture constructor.
 
 ## Named Parameters
 
-`TestCaseSourceAttribute` supports one named parameter:
+`TestFixtureSourceAttribute` supports two named parameters:
 
-* **Category** is used to assign one or more categories to every test case returned from this source.
+* **Category** is used to assign one or more categories to every test fixture returned from this source.
+* **TypeArgs** can be used to explicitly specify the `Type`s to be used when constructing a generic test fixture. (_NUnit 4.5+_)
 
-## Test Case Construction
+## Test Fixture Construction
 
-In constructing tests, NUnit uses each item returned by the enumerator as follows:
+In constructing fixtures, NUnit uses each item returned by the enumerator as follows:
 
-* If it is an object deriving from `TestFixtureParameters`, its properties are used to provide the test case. NUnit
+* If it is an object deriving from `TestFixtureParameters`, its properties are used to provide the test fixture's data. NUnit
   provides the [TestFixtureData](xref:testfixturedata) class for this purpose.
 * If it is an `object[]`, its members are used to provide the arguments for the method. This is the approach taken in
   the examples above.

docs/snippets/Snippets.NUnit/Attributes/TestFixtureSourceAttributeExamples.cs

@@ -0,0 +1,67 @@
+using NUnit.Framework;
+using System.Collections;
+namespace Snippets.NUnit.Attributes
+{
+    public class TestFixtureSourceAttributeExamples
+    {
+        internal static class StaticPropertyInOwnClass
+        {
+            #region StaticPropertyInOwnClass
+            [TestFixtureSource(nameof(FixtureArgs))]
+            public class MyTestClass
+            {
+                public MyTestClass(string word, int num) { /* ... */ }
+
+                /* Tests */
+
+                static object[] FixtureArgs = {
+                    new object[] { "Question", 1 },
+                    new object[] { "Answer", 42 }
+                };
+            }
+            #endregion
+        }
+
+        internal static class StaticPropertyInAnotherClass {
+        #region StaticPropertyInAnotherClass
+        [TestFixtureSource(typeof(AnotherClass), nameof(AnotherClass.FixtureArgs))]
+        public class MyTestClass
+        {
+            public MyTestClass(string word, int num) { /* ... */ }
+
+            /* Tests */
+        }
+
+        public class AnotherClass
+        {
+            public static object[] FixtureArgs = {
+                new object[] { "Question", 1 },
+                new object[] { "Answer", 42 }
+            };
+        }
+        #endregion
+        }
+
+        internal static class SourceFromEnumerable
+        {
+            #region SourceFromEnumerable
+            [TestFixtureSource(typeof(FixtureArgs))]
+            public class MyTestClass
+            {
+                public MyTestClass(string word, int num) { /* ... */ }
+
+                /* ... */
+            }
+
+            class FixtureArgs : IEnumerable
+            {
+                public IEnumerator GetEnumerator()
+                {
+                    yield return new object[] { "Question", 1 };
+                    yield return new object[] { "Answer", 42 };
+                }
+            }
+            #endregion
+        }
+    }
+}

docs/snippets/Snippets.NUnit/Snippets.NUnit.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFrameworks>net8.0</TargetFrameworks>
+        <TargetFrameworks>net9.0</TargetFrameworks>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
         <NoWarn>NUnit2007;NUnit2009;CS7022</NoWarn>

docs/snippets/Snippets.NUnitLite/Snippets.NUnitLite.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net8.0</TargetFramework>
+        <TargetFramework>net9.0</TargetFramework>
         <RootNamespace>Snippets.NUnitLite</RootNamespace>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>