Improve tests and docs (#2941)

* Add a test for the `<namespace>` element.  There were no tests.

* Expand `CanPreserveTypesUsingRegex` to help highlight how it behaves differently from `<namespace>`

* Add more examples to the docs

4 files changed, 98 insertions, 0 deletions

diff --git a/docs/data-formats.md b/docs/data-formats.md
index ef782495b..e360a914b 100644
--- a/docs/data-formats.md
+++ b/docs/data-formats.md
@@ -100,6 +100,21 @@ The `required` attribute specifies that if the type is not marked, during the ma
 </linker>
 ```
 
+### Preserve more than one type within an assembly
+
+```xml
+<linker>
+  <assembly fullname="Assembly">
+    
+    <!-- Preserves all types who's fully qualified type name matches the regular expression -->
+    <type fullname="Assembly.Namespace*" />
+    
+    <!-- Preserve all types within the specified namespace -->
+    <namespace fullname="Assembly.Namespace" /> 
+  </assembly>
+</linker>
+```
+
 ### Preserve only selected fields on a type
 
 ```xml
diff --git a/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveNamespace.cs b/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveNamespace.cs
new file mode 100644
index 000000000..4cca62a47
--- /dev/null
+++ b/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveNamespace.cs
@@ -0,0 +1,51 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Metadata;
+
+namespace Mono.Linker.Tests.Cases.LinkXml
+{
+	[SetupLinkerDescriptorFile ("CanPreserveNamespace.xml")]
+	public class CanPreserveNamespace
+	{
+		public static void Main ()
+		{
+		}
+	}
+}
+
+namespace Mono.Linker.Tests.Cases.LinkXml.PreserveNamespace2
+{
+	[Kept]
+	[KeptMember (".ctor()")]
+	class Type1
+	{
+		[Kept]
+		public int UnusedField;
+	}
+
+	[Kept]
+	[KeptMember (".ctor()")]
+	class Type2
+	{
+		[Kept]
+		public void Method ()
+		{
+		}
+	}
+}
+
+namespace Mono.Linker.Tests.Cases.LinkXml.PreserveNamespace2.SubNamespace
+{
+	class Type1
+	{
+	}
+
+	class Type2
+	{
+		public void Method ()
+		{
+		}
+	}
+}
diff --git a/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveNamespace.xml b/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveNamespace.xml
new file mode 100644
index 000000000..07d798652
--- /dev/null
+++ b/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveNamespace.xml
@@ -0,0 +1,5 @@
+<linker>
+  <assembly fullname="test, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null">
+    <namespace fullname="Mono.Linker.Tests.Cases.LinkXml.PreserveNamespace2" />
+  </assembly>
+</linker>
\ No newline at end of file
diff --git a/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveTypesUsingRegex.cs b/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveTypesUsingRegex.cs
index 54bd66a96..a6e51be4a 100644
--- a/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveTypesUsingRegex.cs
+++ b/test/Mono.Linker.Tests.Cases/LinkXml/CanPreserveTypesUsingRegex.cs
@@ -31,11 +31,38 @@ namespace Mono.Linker.Tests.Cases.LinkXml.PreserveNamespace
 	[KeptMember (".ctor()")]
 	class Type1
 	{
+		[Kept]
+		public int UnusedField;
+	}
+
+	[Kept]
+	[KeptMember (".ctor()")]
+	class Type2
+	{
+		[Kept]
+		public void Method ()
+		{
+		}
+	}
+}
+
+namespace Mono.Linker.Tests.Cases.LinkXml.PreserveNamespace.SubNamespace
+{
+	[Kept]
+	[KeptMember (".ctor()")]
+	class Type1
+	{
+		[Kept]
+		public int UnusedField;
 	}
 
 	[Kept]
 	[KeptMember (".ctor()")]
 	class Type2
 	{
+		[Kept]
+		public void Method ()
+		{
+		}
 	}
 }