From 3549412116c1686eb2be79871593c70dce29d3c3 Mon Sep 17 00:00:00 2001
From: Theodore Tsirpanis <teo@tsirpanis.gr>
Date: Mon, 3 Oct 2022 10:42:25 +0300
Subject: [PATCH] Add tests.

---
 .../Encoding/ControlFlowBuilderTests.cs       | 46 ++++++++++++++++++-
 .../Encoding/InstructionEncoderTests.cs       | 22 +++++++++
 2 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/src/libraries/System.Reflection.Metadata/tests/Metadata/Ecma335/Encoding/ControlFlowBuilderTests.cs b/src/libraries/System.Reflection.Metadata/tests/Metadata/Ecma335/Encoding/ControlFlowBuilderTests.cs
index 93e3ab418286c..37b7ec13dd193 100644
--- a/src/libraries/System.Reflection.Metadata/tests/Metadata/Ecma335/Encoding/ControlFlowBuilderTests.cs
+++ b/src/libraries/System.Reflection.Metadata/tests/Metadata/Ecma335/Encoding/ControlFlowBuilderTests.cs
@@ -361,7 +361,7 @@ public void Branch_LongInstruction_LongDistance()
 
             AssertEx.Equal(new byte[]
             {
-                0x13, 0x30, 0x08, 0x00, 0x0A, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,// header
+                0x13, 0x30, 0x08, 0x00, 0x0A, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // header
                 (byte)ILOpCode.Br, 0x04, 0x01, 0x00, 0x00,
                 (byte)ILOpCode.Call, 0x01, 0x00, 0x00, 0x06,
                 (byte)ILOpCode.Call, 0x01, 0x00, 0x00, 0x06,
@@ -419,6 +419,50 @@ public void Branch_LongInstruction_LongDistance()
             }, builder.ToArray());
         }
 
+        [Fact]
+        public void Switch()
+        {
+            var code = new BlobBuilder();
+            var il = new InstructionEncoder(code, new ControlFlowBuilder());
+
+            var lStart = il.DefineLabel();
+            var l1 = il.DefineLabel();
+            var l2 = il.DefineLabel();
+            var l3 = il.DefineLabel();
+
+            il.OpCode(ILOpCode.Nop);
+            il.MarkLabel(lStart);
+            var switchEncoder = il.Switch(4);
+            switchEncoder.Branch(l1);
+            switchEncoder.Branch(l2);
+            switchEncoder.Branch(l3);
+            switchEncoder.Branch(lStart);
+
+            il.MarkLabel(l1);
+            il.OpCode(ILOpCode.Nop);
+            il.MarkLabel(l2);
+            il.OpCode(ILOpCode.Nop);
+            il.MarkLabel(l3);
+            il.OpCode(ILOpCode.Nop);
+
+            var builder = new BlobBuilder();
+            new MethodBodyStreamEncoder(builder).AddMethodBody(il);
+
+            AssertEx.Equal(new byte[]
+            {
+                0x66, // header
+                (byte)ILOpCode.Nop,
+                (byte)ILOpCode.Switch, 0x04, 0x00, 0x00, 0x00,
+                0x00, 0x00, 0x00, 0x00,
+                0x01, 0x00, 0x00, 0x00,
+                0x02, 0x00, 0x00, 0x00,
+                0xeb, 0xff, 0xff, 0xff,
+                (byte)ILOpCode.Nop,
+                (byte)ILOpCode.Nop,
+                (byte)ILOpCode.Nop
+            }, builder.ToArray());
+        }
+
         [Fact]
         public void Clear()
         {
diff --git a/src/libraries/System.Reflection.Metadata/tests/Metadata/Ecma335/Encoding/InstructionEncoderTests.cs b/src/libraries/System.Reflection.Metadata/tests/Metadata/Ecma335/Encoding/InstructionEncoderTests.cs
index 063ad0766ad58..0b85e79472ba9 100644
--- a/src/libraries/System.Reflection.Metadata/tests/Metadata/Ecma335/Encoding/InstructionEncoderTests.cs
+++ b/src/libraries/System.Reflection.Metadata/tests/Metadata/Ecma335/Encoding/InstructionEncoderTests.cs
@@ -475,6 +475,28 @@ public void Branch()
             }, builder.ToArray());
         }
 
+        [Fact]
+        public void Switch()
+        {
+            var builder = new BlobBuilder();
+            var il = new InstructionEncoder(builder, new ControlFlowBuilder());
+            var l = il.DefineLabel();
+            var switchEncoder = il.Switch(4);
+            switchEncoder.Branch(l);
+            switchEncoder.Branch(l);
+            switchEncoder.Branch(l);
+            switchEncoder.Branch(l);
+
+            AssertEx.Equal(new byte[]
+            {
+                (byte)ILOpCode.Switch, 0x04, 0x00, 0x00, 0x00,
+                0xff, 0xff, 0xff, 0xff,
+                0xff, 0xff, 0xff, 0xff,
+                0xff, 0xff, 0xff, 0xff,
+                0xff, 0xff, 0xff, 0xff
+            }, builder.ToArray());
+        }
+
         [Fact]
         public void BranchAndLabel_Errors()
         {