Remove the C#-specific field_presence_test.proto, using unittest_no_field_presence.proto instead.

This is the start of establishing a C# namespace of "Google.ProtocolBuffers.TestProtos.Proto3" for proto3-syntax protos.
We could optionally split the directory structure as well into Proto2 and Proto3 for clarity.

csharp/protos/google/protobuf/field_presence_test.proto

-syntax = "proto3";
-
-package Google.ProtocolBuffers.TestProtos.FieldPresence;
-
-// TODO(jieluo): Add repeated fields, oneof, maps to TestAllTypes 
-message TestAllTypes {
-  enum NestedEnum {
-    FOO = 0;
-    BAR = 1;
-    BAZ = 2;
-  }
-  message NestedMessage {
-    optional int32 value = 1;
-  }
-
-  optional int32 optional_int32 = 1;
-  optional string optional_string = 2;
-  optional bytes optional_bytes = 3;
-  optional NestedEnum optional_nested_enum = 4;
-  optional NestedMessage optional_nested_message = 5;
-}

csharp/src/ProtocolBuffers.Test/FieldPresenceTest.cs

@@ -33,7 +33,7 @@
 
 using System;
 using Google.ProtocolBuffers.Descriptors;
-using Google.ProtocolBuffers.TestProtos.FieldPresence;
+using Google.ProtocolBuffers.TestProtos.Proto3;
 using NUnit.Framework;
 
 namespace Google.ProtocolBuffers
@@ -177,7 +177,7 @@ namespace Google.ProtocolBuffers
             Assert.AreEqual(ByteString.Empty, message.OptionalBytes);
             Assert.AreEqual(TestAllTypes.Types.NestedEnum.FOO, message.OptionalNestedEnum);
             Assert.IsTrue(message.HasOptionalNestedMessage);
-            Assert.AreEqual(0, message.OptionalNestedMessage.Value);
+            Assert.AreEqual(0, message.OptionalNestedMessage.Bb);
         }
     }
 }

csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj

@@ -84,7 +84,6 @@
     <Compile Include="Compatibility\TestResources.cs" />
     <Compile Include="Compatibility\TextCompatibilityTests.cs" />
     <Compile Include="Compatibility\XmlCompatibilityTests.cs" />
-    <Compile Include="TestProtos\FieldPresenceTest.cs" />
     <Compile Include="TestProtos\GoogleSize.cs" />
     <Compile Include="TestProtos\GoogleSpeed.cs" />
     <Compile Include="TestProtos\Unittest.cs" />
@@ -96,6 +95,7 @@
     <Compile Include="TestProtos\UnittestImportPublic.cs" />
     <Compile Include="TestProtos\UnittestIssues.cs" />
     <Compile Include="TestProtos\UnittestMset.cs" />
+    <Compile Include="TestProtos\UnittestNoFieldPresence.cs" />
     <Compile Include="TestProtos\UnittestOptimizeFor.cs" />
     <Compile Include="TestProtos\UnknownEnumTest.cs" />
     <Compile Include="TestResources.cs" />

src/google/protobuf/unittest_no_field_presence.proto

@@ -37,7 +37,7 @@ import "google/protobuf/unittest.proto";
 
 package proto2_nofieldpresence_unittest;
 
-option csharp_namespace = "Google.ProtocolBuffers.TestProtos";
+option csharp_namespace = "Google.ProtocolBuffers.TestProtos.Proto3";
 
 // This proto includes every type of field in both singular and repeated
 // forms.