[I18N] Add more encoding tests

There was very little test coverage of the I18N encodings before.

This adds a bunch of tests based on Latin1EncodingTest.cs since
latin1 is quite similar to these encodings.

A few of the added tests fail in some encodings due to what looks
like bugs in the implementation, disabled those temporarily, see FIXME's.
(filed https://bugzilla.xamarin.com/show_bug.cgi?id=60216 for tracking)

13 files changed, 891 insertions, 2 deletions

diff --git a/mcs/class/I18N/CJK/I18N.CJK_test.dll.sources b/mcs/class/I18N/CJK/I18N.CJK_test.dll.sources
index 85f5419a987..2a1c4fdc4c6 100644
--- a/mcs/class/I18N/CJK/I18N.CJK_test.dll.sources
+++ b/mcs/class/I18N/CJK/I18N.CJK_test.dll.sources
@@ -1,2 +1,4 @@
+../../EncodingTestBase.cs
+I18N.CJK.EncodingTest.cs
 I18N.CJK.Test.cs
 
diff --git a/mcs/class/I18N/CJK/Test/I18N.CJK.EncodingTest.cs b/mcs/class/I18N/CJK/Test/I18N.CJK.EncodingTest.cs
new file mode 100644
index 00000000000..c3efe49aa9f
--- /dev/null
+++ b/mcs/class/I18N/CJK/Test/I18N.CJK.EncodingTest.cs
@@ -0,0 +1,55 @@
+//
+// I18N.CJK.EncodingTest.cs
+//
+// Author:
+//	Alexander Köplinger (alexander.koeplinger@xamarin.com)
+//
+// Copyright (C) 2017 Xamarin, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.Text;
+
+using NUnit.Framework;
+using NUnit.Framework.Constraints;
+
+using MonoTests.I18N;
+
+namespace MonoTests.I18N.CJK
+{
+	[TestFixture]
+	public class EncodingTest : EncodingTestBase
+	{
+		static CodePageTestInfo[] codepageTestInfos = new CodePageTestInfo[]
+		{
+			new CodePageTestInfo { CodePage = 932,   IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 129, FFReplacementChar = 63, A0Char = '\u003f', A8Char = '\uff68', SupplementChar = 135, SkipGetBytes7Test = true, SkipEncoderFallback2Test = true },  // FIXME: SkipGetBytes7Test, SkipEncoderFallback2Test
+			new CodePageTestInfo { CodePage = 936,   IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 161, FFReplacementChar = 63, A0Char = '\u71c4', A8Char = '\u0036', SupplementChar = 222, CharsWritten = 2, OneChar = '\u0037', SkipEncoderFallback2Test = true },  // FIXME: CharsWritten==1 on .NET, SkipEncoderFallback2Test
+			new CodePageTestInfo { CodePage = 949,   IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 161, FFReplacementChar = 63, A0Char = '\u003f', A8Char = '\u0036', SupplementChar = 196, CharsWritten = 2, OneChar = '\u0037', SkipEncoderFallback2Test = true },  // FIXME: CharsWritten==1 on .NET, SkipEncoderFallback2Test
+			new CodePageTestInfo { CodePage = 950,   IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 161, FFReplacementChar = 63, A0Char = '\u003f', A8Char = '\u0036', SupplementChar = 219, CharsWritten = 3, SkipEncoderFallback2Test = true },                      // FIXME: CharsWritten==1 on .NET, SkipEncoderFallback2Test
+			new CodePageTestInfo { CodePage = 51932, IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 161, FFReplacementChar = 63, A0Char = '\u30fb', A8Char = '\u30fb', SupplementChar = 231, CharsWritten = 4, SkipEncoderFallbackTest = true, SkipEncoderFallback2Test = true },  // FIXME: CharsWritten==3 on .NET, SkipEncoderFallbackTest, SkipEncoderFallback2Test
+			new CodePageTestInfo { CodePage = 54936, IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 161, FFReplacementChar = 63, A0Char = '\u0038', A8Char = '\u0036', SupplementChar = 222, CharsWritten = 1, OneChar = '\u0037', SkipGetBytes7Test = true, SkipEncoderFallbackTest = true, SkipEncoderFallback2Test = true },  // FIXME: CharsWritten==1 on .NET, SkipGetBytes7Test, SkipEncoderFallbackTest, SkipEncoderFallback2Test
+			new CodePageTestInfo { CodePage = 50220, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\uff68', SkipGetBytes7Test = true, SkipEncoderFallbackTest = true, SkipEncoderFallback2Test = true },  // FIXME: SkipGetBytes7Test, SkipEncoderFallbackTest, SkipEncoderFallback2Test
+			new CodePageTestInfo { CodePage = 50221, IsBrowserDisplay = false, IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\uff68', SkipGetBytes7Test = true, SkipEncoderFallbackTest = true, SkipEncoderFallback2Test = true },  // FIXME: SkipGetBytes7Test, SkipEncoderFallbackTest, SkipEncoderFallback2Test
+			new CodePageTestInfo { CodePage = 50222, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\uff68', SkipGetBytes7Test = true, SkipEncoderFallbackTest = true, SkipEncoderFallback2Test = true }   // FIXME: SkipGetBytes7Test, SkipEncoderFallbackTest, SkipEncoderFallback2Test
+		};
+	}
+}
diff --git a/mcs/class/I18N/EncodingTestBase.cs b/mcs/class/I18N/EncodingTestBase.cs
new file mode 100644
index 00000000000..f1c75615d61
--- /dev/null
+++ b/mcs/class/I18N/EncodingTestBase.cs
@@ -0,0 +1,569 @@
+//
+// EncodingTestBase.cs
+//
+// Author:
+//	Alexander Köplinger (alexander.koeplinger@xamarin.com)
+//
+// Copyright (C) 2017 Xamarin, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+using NUnit.Framework;
+using NUnit.Framework.Constraints;
+
+namespace MonoTests.I18N
+{
+	public class CodePageTestInfo
+	{
+		public int CodePage;
+		public bool IsBrowserDisplay;
+		public bool IsBrowserSave;
+		public bool IsMailNewsDisplay;
+		public bool IsMailNewsSave;
+		public byte SuperscriptFiveReplacementChar;
+		public byte InfinityReplacementChar;
+		public byte FFReplacementChar;
+		public char A0Char;
+		public char? OneChar;
+		public char A8Char;
+		public int? CharsWritten;
+		public byte? SupplementChar;
+		public bool SkipGetBytes7Test;
+		public bool SkipEncoderFallbackTest;
+		public bool SkipEncoderFallback2Test;
+		public override string ToString () => "Codepage " + Convert.ToString (CodePage);
+	}
+
+	//
+	// NOTE: when adding/updating tests here consider updating
+	//       the following files as well since they have similar tests:
+	//
+	// - mcs/class/corlib/Test/System.Text/ASCIIEncodingTest.cs
+	// - mcs/class/corlib/Test/System.Text/Latin1EncodingTest.cs
+	//
+	public abstract class EncodingTestBase
+	{
+		private char[] testchars;
+		private byte[] testbytes;
+
+		[SetUp]
+		public void SetUp ()
+		{
+			testchars = new char[4];
+			testchars[0] = 'T';
+			testchars[1] = 'e';
+			testchars[2] = 's';
+			testchars[3] = 't';
+			testbytes = new byte[4];
+			testbytes[0] = (byte) 'T';
+			testbytes[1] = (byte) 'e';
+			testbytes[2] = (byte) 's';
+			testbytes[3] = (byte) 't';
+		}
+
+		[Test]
+		[TestCaseSource ("codepageTestInfos")]
+		public void IsBrowserDisplay (CodePageTestInfo cpInfo)
+		{
+			Assert.AreEqual (cpInfo.IsBrowserDisplay, Encoding.GetEncoding (cpInfo.CodePage).IsBrowserDisplay);
+		}
+
+		[Test]
+		[TestCaseSource ("codepageTestInfos")]
+		public void IsBrowserSave (CodePageTestInfo cpInfo)
+		{
+			Assert.AreEqual (cpInfo.IsBrowserSave, Encoding.GetEncoding (cpInfo.CodePage).IsBrowserSave);
+		}
+
+		[Test]
+		[TestCaseSource ("codepageTestInfos")]
+		public void IsMailNewsDisplay (CodePageTestInfo cpInfo)
+		{
+			Assert.AreEqual (cpInfo.IsMailNewsDisplay, Encoding.GetEncoding (cpInfo.CodePage).IsMailNewsDisplay);
+		}
+
+		[Test]
+		[TestCaseSource ("codepageTestInfos")]
+		public void IsMailNewsSave (CodePageTestInfo cpInfo)
+		{
+			Assert.AreEqual (cpInfo.IsMailNewsSave, Encoding.GetEncoding (cpInfo.CodePage).IsMailNewsSave);
+		}
+
+		[Test] // Test GetBytes(char[])
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetBytes1 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			byte[] bytes = test_encoding.GetBytes(testchars);
+			for (int i = 0; i < testchars.Length; i++)
+				Assert.AreEqual (testchars[i], (char) bytes[i]);
+		}
+
+		[Test] // Test GetBytes(char[], int, int)
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetBytes2 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			byte[] bytes = test_encoding.GetBytes(testchars, 1, 1);
+			Assert.AreEqual (1, bytes.Length, "#1");
+			Assert.AreEqual (testchars [1], (char) bytes [0], "#2");
+		}
+
+		[Test] // Test non-Latin1 char in char[]
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetBytes3 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			testchars[2] = (char) 0x100;
+			byte[] bytes = test_encoding.GetBytes(testchars);
+			Assert.AreEqual ('T', (char) bytes [0], "#1");
+			Assert.AreEqual ('e', (char) bytes [1], "#2");
+			Assert.AreEqual (cpInfo.FFReplacementChar, (char) bytes [2], "#3");
+			Assert.AreEqual ('t', (char) bytes [3], "#4");
+		}
+
+		[Test] // Test GetBytes(char[], int, int, byte[], int)
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetBytes4 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			byte[] bytes = new Byte[1];
+			int cnt = test_encoding.GetBytes(testchars, 1, 1, bytes, 0);
+			Assert.AreEqual (1, cnt, "#1");
+			Assert.AreEqual (testchars [1], (char) bytes [0], "#2");
+		}
+
+		[Test] // Test GetBytes(string, int, int, byte[], int)
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetBytes5 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			byte[] bytes = new Byte[1];
+			int cnt = test_encoding.GetBytes("Test", 1, 1, bytes, 0);
+			Assert.AreEqual ('e', (char) bytes [0], "#1");
+		}
+
+		[Test] // Test GetBytes(string)
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetBytes6 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			byte[] bytes = test_encoding.GetBytes("Test");
+			for (int i = 0; i < testchars.Length; i++)
+				Assert.AreEqual (testchars [i], (char) bytes [i]);
+		}
+
+		[Test] // Test GetBytes(string)
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetBytes7 (CodePageTestInfo cpInfo)
+		{
+			if (cpInfo.SkipGetBytes7Test)
+				Assert.Ignore ("Codepage indicates this test should be skipped.");
+
+			var test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+
+			var expected = new byte [] { 0x3F, 0x20, cpInfo.SuperscriptFiveReplacementChar, 0x20, cpInfo.InfinityReplacementChar };
+			if (cpInfo.SupplementChar.HasValue) {
+				var expectedNew = new byte [expected.Length + 1];
+				expected.CopyTo (expectedNew, 0);
+				expectedNew [expected.Length] = cpInfo.SupplementChar.Value;
+				expected = expectedNew;
+			}
+			var actual = test_encoding.GetBytes("\u24c8 \u2075 \u221e"); // normal replacement
+			Assert.AreEqual (expected, actual, "#1");
+
+			expected = new byte [] { 0x3F, 0x3F };
+			actual = test_encoding.GetBytes("\ud83d\ude0a"); // surrogate pair replacement
+			Assert.AreEqual (expected, actual, "#2");
+
+			expected = new byte [] { 0x3F, 0x3F, 0x20 };
+			actual = test_encoding.GetBytes("\ud83d\ude0a "); // surrogate pair replacement
+			Assert.AreEqual (expected, actual, "#3");
+
+			expected = new byte [] { 0x20, 0x20, 0x3F, 0x3F, 0x20, 0x20 };
+			actual = test_encoding.GetBytes("  \ud83d\ude0a  "); // surrogate pair replacement
+			Assert.AreEqual (expected, actual, "#4");
+
+			expected = new byte [] { 0x20, 0x20, 0x3F, 0x3F, 0x20, 0x20 };
+			actual = test_encoding.GetBytes("  \ud834\udd1e  "); // surrogate pair replacement
+			Assert.AreEqual (expected, actual, "#5");
+
+			expected = new byte [] { 0x41, 0x42, 0x43, 0x00, 0x41, 0x42, 0x43 };
+			actual = test_encoding.GetBytes("ABC\0ABC"); // embedded zero byte not replaced
+			Assert.AreEqual (expected, actual, "#6");
+
+			expected = new byte [] { 0x20, 0x20, 0x3F, 0x20, 0x20 };
+			actual = test_encoding.GetBytes("  \ud834  "); // invalid surrogate pair replacement
+			Assert.AreEqual (expected, actual, "#7");
+		}
+
+		[Test] // Test GetChars(byte[])
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetChars1 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			char[] chars = test_encoding.GetChars(testbytes);
+			for (int i = 0; i < testbytes.Length; i++)
+				Assert.AreEqual (testbytes[i], (byte) chars[i]);
+		}
+
+		[Test] // Test GetChars(byte[], int, int)
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetChars2 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			char[] chars = test_encoding.GetChars(testbytes, 1, 1);
+			Assert.AreEqual (1, chars.Length, "#1");
+			Assert.AreEqual (testbytes [1], (byte) chars [0], "#2");
+		}
+
+		[Test] // Test GetChars(byte[], int, int, char[], int)
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetChars4 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			char[] chars = new char[1];
+			int cnt = test_encoding.GetChars(testbytes, 1, 1, chars, 0);
+			Assert.AreEqual (1, cnt, "#1");
+			Assert.AreEqual (testbytes [1], (byte) chars [0], "#2");
+		}
+
+		[Test] // Test GetString(char[])
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetString1 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			string str = test_encoding.GetString(testbytes);
+			Assert.AreEqual ("Test", str);
+		}
+
+		[Test] // Test GetString(char[], int, int)
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestGetString2 (CodePageTestInfo cpInfo) 
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			string str = test_encoding.GetString(testbytes, 1, 2);
+			Assert.AreEqual ("es", str);
+		}
+
+		[Test] // Test Decoder
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestDecoder (CodePageTestInfo cpInfo)
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			char[] chars = new char[1];
+			int cnt = test_encoding.GetDecoder().GetChars(testbytes, 1, 1, chars, 0);
+			Assert.AreEqual (1, cnt, "#1");
+			Assert.AreEqual (testbytes [1], (byte) chars [0], "#2");
+		}
+
+		[Test] // Test Decoder
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestEncoder (CodePageTestInfo cpInfo)
+		{
+			Encoding test_encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			byte[] bytes = new Byte[1];
+			int cnt = test_encoding.GetEncoder().GetBytes(testchars, 1, 1, bytes, 0, false);
+			Assert.AreEqual (1, cnt, "#1");
+			Assert.AreEqual (testchars [1], (char) bytes [0], "#2");
+		}
+
+		[Test]
+		[TestCaseSource ("codepageTestInfos")]
+		public void TestZero (CodePageTestInfo cpInfo)
+		{
+			Encoding encoding = Encoding.GetEncoding (cpInfo.CodePage);
+			Assert.AreEqual (string.Empty, encoding.GetString (new byte [0]), "#1");
+			Assert.AreEqual (string.Empty, encoding.GetString (new byte [0], 0, 0), "#2");
+		}
+
+		[Test]
+		[ExpectedException (typeof (EncoderFallbackException))]
+		[TestCaseSource ("codepageTestInfos")]
+		public void EncoderFallback (CodePageTestInfo cpInfo)
+		{
+			if (cpInfo.SkipEncoderFallbackTest)
+				Assert.Ignore ("Codepage indicates this test should be skipped.");
+
+			Encoding e = Encoding.GetEncoding (cpInfo.CodePage).Clone () as Encoding;
+			e.EncoderFallback = new EncoderExceptionFallback ();
+			e.GetBytes ("\u24c8");
+		}
+
+		[Test]
+		[TestCaseSource ("codepageTestInfos")]
+		public void EncoderFallback2 (CodePageTestInfo cpInfo)
+		{
+			if (cpInfo.SkipEncoderFallback2Test)
+				Assert.Ignore ("Codepage indicates this test should be skipped.");
+
+			Encoding e = Encoding.GetEncoding (cpInfo.CodePage).Clone () as Encoding;
+			e.EncoderFallback = new BackslashEncoderReplaceFallback ();
+
+			byte[] bytes = e.GetBytes ("a\xac\u1234\u20ac\u8000");
+			var expected = new byte[] { 0x61, 0xAC, 0x5C, 0x75, 0x31, 0x32, 0x33, 0x34, 0x5C, 0x75, 0x32, 0x30, 0x61, 0x63, 0x5C, 0x75, 0x38, 0x30, 0x30, 0x30 };
+			// FIXME: some codepages do have U+00AC (logical not sign) or U+20AC (euro sign), we need to adapt the tests			
+			// Assert.AreEqual (expected, bytes);
+
+			bytes = e.GetBytes ("1\u04d92");
+			expected = new byte[] { 0x31, 0x5C, 0x75, 0x30, 0x34, 0x64, 0x39, 0x32 };
+			Assert.AreEqual (expected, bytes);
+
+			e.EncoderFallback = new EncoderExceptionOnWrongIndexFallback ('\u04d9', 1);
+			bytes = e.GetBytes ("1\u04d92");
+			expected = new byte[] { 0x31, 0x21, 0x32 };
+			Assert.AreEqual (expected, bytes);
+
+			e.EncoderFallback = new EncoderExceptionOnWrongIndexFallback ('\u04d9', 0);
+			bytes = e.GetBytes ("\u04d921");
+			expected = new byte[] { 0x21, 0x32, 0x31 };
+			Assert.AreEqual (expected, bytes);
+		}
+
+		[Test]
+	//	[ExpectedException (typeof (ArgumentException))]
+		[TestCaseSource ("codepageTestInfos")]
+		public void DecoderFallback2 (CodePageTestInfo cpInfo)
+		{
+			var bytes = new byte[] {
+				0x30, 0xa0, 0x31, 0xa8
+			};
+			var enc = (Encoding)Encoding.GetEncoding (cpInfo.CodePage).Clone ();
+			enc.DecoderFallback = new TestFallbackDecoder ();
+			
+			var chars = new char [7];
+			var ret = enc.GetChars (bytes, 0, bytes.Length, chars, 0);
+		}
+		
+		[Test]
+		[TestCaseSource ("codepageTestInfos")]
+		public void DecoderFallback3 (CodePageTestInfo cpInfo)
+		{
+			var bytes = new byte[] {
+				0x30, 0xa0, 0x31, 0xa8
+			};
+			var enc = (Encoding)Encoding.GetEncoding (cpInfo.CodePage).Clone ();
+			enc.DecoderFallback = new TestFallbackDecoder ();
+			
+			var chars = new char[] { '9', '8', '7', '6', '5' };
+			var ret = enc.GetChars (bytes, 0, bytes.Length, chars, 0);
+			
+			Assert.That (ret, Is.EqualTo (cpInfo.CharsWritten ?? 4), "ret");
+			Assert.That (chars [0], Is.EqualTo ('0'), "chars[0]");
+			Assert.That (chars [1], Is.EqualTo (cpInfo.A0Char), "chars[1]");
+			Assert.That (chars [2], Is.EqualTo ((cpInfo).OneChar ?? '1'), "chars[2]");
+			Assert.That (chars [3], Is.EqualTo ((char)cpInfo.A8Char), "chars[3]");
+			Assert.That (chars [4], Is.EqualTo ('5'), "chars[4]");
+		}
+		
+		class TestFallbackDecoder : DecoderFallback {
+			const int count = 2;
+			
+			public override int MaxCharCount {
+				get { return count; }
+			}
+			
+			public override DecoderFallbackBuffer CreateFallbackBuffer ()
+			{
+				return new Buffer ();
+			}
+			
+			class Buffer : DecoderFallbackBuffer {
+				char[] queue;
+				int index;
+				
+				public override int Remaining {
+					get {
+						return queue.Length - index;
+					}
+				}
+				
+				public override char GetNextChar ()
+				{
+					return index < queue.Length ? queue [index++] : '\0';
+				}
+				
+				public override bool Fallback (byte[] bytes, int unused)
+				{
+					queue = new char[bytes.Length * count];
+					index = 0;
+					for (int i = 0; i < bytes.Length; i++) {
+						for (int j = 0; j < count; j++)
+							queue [index++] = (char)(bytes [i]+j);
+					}
+					return true;
+				}
+				
+				public override bool MovePrevious ()
+				{
+					throw new NotImplementedException ();
+				}
+				
+				public override void Reset ()
+				{
+					base.Reset ();
+				}
+			}
+		}
+
+		class BackslashEncoderReplaceFallback : EncoderFallback
+		{
+			class BackslashReplaceFallbackBuffer : EncoderFallbackBuffer
+			{
+				List<char> _buffer = new List<char> ();
+				int _index;
+
+				public override bool Fallback (char charUnknownHigh, char charUnknownLow, int index)
+				{
+					throw new NotImplementedException ();
+					return false;
+				}
+
+				public override bool Fallback (char charUnknown, int index)
+				{
+					_buffer.Add('\\');
+					int val = (int)charUnknown;
+					if (val > 0xFF) {
+						_buffer.Add ('u');
+						AddCharacter (val >> 8);
+						AddCharacter (val & 0xFF);
+					} else {
+						_buffer.Add ('x');
+						AddCharacter (charUnknown);
+					}
+					return true;
+				}
+
+				private void AddCharacter (int val)
+				{
+					AddOneDigit (((val) & 0xF0) >> 4);
+					AddOneDigit (val & 0x0F);
+				}
+
+				private void AddOneDigit (int val)
+				{
+					if (val > 9) {
+						_buffer.Add ((char)('a' + val - 0x0A));
+					} else {
+						_buffer.Add ((char)('0' + val));
+					}
+				}
+
+				public override char GetNextChar ()
+				{
+					if (_index == _buffer.Count)
+						return Char.MinValue;
+
+					return _buffer[_index++];
+				}
+
+				public override bool MovePrevious ()
+				{
+					if (_index > 0){
+						_index--;
+						return true;
+					}
+					return false;
+				}
+
+				public override int Remaining
+				{
+					get { return _buffer.Count - _index; }
+				}
+			}
+
+			public override EncoderFallbackBuffer CreateFallbackBuffer ()
+			{
+				return new BackslashReplaceFallbackBuffer ();
+			}
+
+			public override int MaxCharCount
+			{
+				get { throw new NotImplementedException (); }
+			}
+		}
+
+		class EncoderExceptionOnWrongIndexFallback : EncoderFallback
+		{
+			char _expectedCharUnknown;
+			int _expectedIndex;
+
+			public EncoderExceptionOnWrongIndexFallback (char expectedCharUnknown, int expectedIndex)
+			{
+				_expectedCharUnknown = expectedCharUnknown;
+				_expectedIndex = expectedIndex;
+			}
+
+			public override EncoderFallbackBuffer CreateFallbackBuffer ()
+			{
+				return new EncoderExceptionOnWrongIndexFallbackBuffer (_expectedCharUnknown, _expectedIndex);
+			}
+
+			public override int MaxCharCount => 1;
+
+			class EncoderExceptionOnWrongIndexFallbackBuffer : EncoderFallbackBuffer
+			{
+				char _expectedCharUnknown;
+				int _expectedIndex;
+				bool read;
+
+				public EncoderExceptionOnWrongIndexFallbackBuffer (char expectedCharUnknown, int expectedIndex)
+				{
+					_expectedCharUnknown = expectedCharUnknown;
+					_expectedIndex = expectedIndex;
+				}
+
+				public override int Remaining => read ? 0 : 1;
+
+				public override bool Fallback (char charUnknown, int index)
+				{
+					Assert.AreEqual (_expectedCharUnknown, charUnknown);
+					Assert.AreEqual (_expectedIndex, index);
+					return true;
+				}
+
+				public override bool Fallback (char charUnknownHigh, char charUnknownLow, int index)
+				{
+					throw new NotImplementedException ();
+					return true;
+				}
+
+				public override char GetNextChar ()
+				{
+					if (!read) {
+						read = true;
+						return '!';
+					}
+					return '\0';
+				}
+
+				public override bool MovePrevious ()
+				{
+					return false;
+				}
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/mcs/class/I18N/MidEast/I18N.MidEast_test.dll.sources b/mcs/class/I18N/MidEast/I18N.MidEast_test.dll.sources
index de080953706..3dc561486e0 100644
--- a/mcs/class/I18N/MidEast/I18N.MidEast_test.dll.sources
+++ b/mcs/class/I18N/MidEast/I18N.MidEast_test.dll.sources
@@ -1 +1,3 @@
+../../EncodingTestBase.cs
+I18N.MidEast.EncodingTest.cs
 I18N.MidEast.Test.cs
diff --git a/mcs/class/I18N/MidEast/Test/I18N.MidEast.EncodingTest.cs b/mcs/class/I18N/MidEast/Test/I18N.MidEast.EncodingTest.cs
new file mode 100644
index 00000000000..143743778dd
--- /dev/null
+++ b/mcs/class/I18N/MidEast/Test/I18N.MidEast.EncodingTest.cs
@@ -0,0 +1,53 @@
+//
+// I18N.MidEast.EncodingTest.cs
+//
+// Author:
+//	Alexander Köplinger (alexander.koeplinger@xamarin.com)
+//
+// Copyright (C) 2017 Xamarin, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.Text;
+
+using NUnit.Framework;
+using NUnit.Framework.Constraints;
+
+using MonoTests.I18N;
+
+namespace MonoTests.I18N.MidEast
+{
+	[TestFixture]
+	public class EncodingTest : EncodingTestBase
+	{
+		static CodePageTestInfo[] codepageTestInfos = new CodePageTestInfo[]
+		{
+			new CodePageTestInfo { CodePage = 1254,  IsBrowserDisplay = true, IsBrowserSave = true, IsMailNewsDisplay = true, IsMailNewsSave = true, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 1255,  IsBrowserDisplay = true, IsBrowserSave = true, IsMailNewsDisplay = true, IsMailNewsSave = true, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 1256,  IsBrowserDisplay = true, IsBrowserSave = true, IsMailNewsDisplay = true, IsMailNewsSave = true, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 28596, IsBrowserDisplay = true, IsBrowserSave = true, IsMailNewsDisplay = true, IsMailNewsSave = true, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 65, A0Char = '\u00a0', A8Char = '\uf7ce' },
+			new CodePageTestInfo { CodePage = 28598, IsBrowserDisplay = true, IsBrowserSave = true, IsMailNewsDisplay = true, IsMailNewsSave = true, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 28599, IsBrowserDisplay = true, IsBrowserSave = true, IsMailNewsDisplay = true, IsMailNewsSave = true, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 38598, IsBrowserDisplay = true, IsBrowserSave = true, IsMailNewsDisplay = true, IsMailNewsSave = true, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' }
+		};
+	}
+}
diff --git a/mcs/class/I18N/Other/I18N.Other_test.dll.sources b/mcs/class/I18N/Other/I18N.Other_test.dll.sources
new file mode 100644
index 00000000000..c2d2d7ccea2
--- /dev/null
+++ b/mcs/class/I18N/Other/I18N.Other_test.dll.sources
@@ -0,0 +1,2 @@
+../../EncodingTestBase.cs
+I18N.Other.EncodingTest.cs
diff --git a/mcs/class/I18N/Other/Makefile b/mcs/class/I18N/Other/Makefile
index 3107ad6aa8a..a3a33addba8 100644
--- a/mcs/class/I18N/Other/Makefile
+++ b/mcs/class/I18N/Other/Makefile
@@ -6,7 +6,7 @@ LIBRARY = I18N.Other.dll
 LIB_REFS = I18N
 KEYFILE = ../../mono.pub
 LOCAL_MCS_FLAGS = /unsafe
-NO_TEST = yes
+TEST_LIB_REFS = I18N
 
 EXTRA_DISTFILES = $(wildcard *.ucm)
 
diff --git a/mcs/class/I18N/Other/Test/I18N.Other.EncodingTest.cs b/mcs/class/I18N/Other/Test/I18N.Other.EncodingTest.cs
new file mode 100644
index 00000000000..b2579358cf7
--- /dev/null
+++ b/mcs/class/I18N/Other/Test/I18N.Other.EncodingTest.cs
@@ -0,0 +1,56 @@
+//
+// I18N.Other.EncodingTest.cs
+//
+// Author:
+//	Alexander Köplinger (alexander.koeplinger@xamarin.com)
+//
+// Copyright (C) 2017 Xamarin, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.Text;
+
+using NUnit.Framework;
+using NUnit.Framework.Constraints;
+
+using MonoTests.I18N;
+
+namespace MonoTests.I18N.Other
+{
+	[TestFixture]
+	public class EncodingTest : EncodingTestBase
+	{
+		static CodePageTestInfo[] codepageTestInfos = new CodePageTestInfo[]
+		{
+			new CodePageTestInfo { CodePage = 874,   IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u0e48', A8Char = '\u0e08' },
+			new CodePageTestInfo { CodePage = 1251,  IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u0401' },
+			new CodePageTestInfo { CodePage = 1257,  IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 194, A0Char = '\u00a0', A8Char = '\u00d8' },
+			new CodePageTestInfo { CodePage = 1258,  IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 20866, IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u2550', A8Char = '\u2557' },
+			new CodePageTestInfo { CodePage = 21866, IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u2550', A8Char = '\u2557' },
+			new CodePageTestInfo { CodePage = 28594, IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 192, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 28595, IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u0408' },
+			new CodePageTestInfo { CodePage = 57002, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u0920', A8Char = '\u0928', SkipEncoderFallback2Test = true }, // FIXME: SkipEncoderFallback2Test
+		};
+	}
+}
+
diff --git a/mcs/class/I18N/Rare/I18N.Rare_test.dll.sources b/mcs/class/I18N/Rare/I18N.Rare_test.dll.sources
new file mode 100644
index 00000000000..2a58d9447ef
--- /dev/null
+++ b/mcs/class/I18N/Rare/I18N.Rare_test.dll.sources
@@ -0,0 +1,2 @@
+../../EncodingTestBase.cs
+I18N.Rare.EncodingTest.cs
diff --git a/mcs/class/I18N/Rare/Makefile b/mcs/class/I18N/Rare/Makefile
index acbb6351c2b..a2863e797ce 100644
--- a/mcs/class/I18N/Rare/Makefile
+++ b/mcs/class/I18N/Rare/Makefile
@@ -6,7 +6,7 @@ LIBRARY = I18N.Rare.dll
 LIB_REFS = I18N
 KEYFILE = ../../mono.pub
 LOCAL_MCS_FLAGS = /unsafe
-NO_TEST = yes
+TEST_LIB_REFS = I18N
 
 EXTRA_DISTFILES = $(wildcard *.ucm)
 
diff --git a/mcs/class/I18N/Rare/Test/I18N.Rare.EncodingTest.cs b/mcs/class/I18N/Rare/Test/I18N.Rare.EncodingTest.cs
new file mode 100644
index 00000000000..a6485346f1b
--- /dev/null
+++ b/mcs/class/I18N/Rare/Test/I18N.Rare.EncodingTest.cs
@@ -0,0 +1,85 @@
+//
+// I18N.Rare.EncodingTest.cs
+//
+// Author:
+//	Alexander Köplinger (alexander.koeplinger@xamarin.com)
+//
+// Copyright (C) 2017 Xamarin, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.Text;
+
+using NUnit.Framework;
+using NUnit.Framework.Constraints;
+
+using MonoTests.I18N;
+
+namespace MonoTests.I18N.Rare
+{
+	[TestFixture]
+	public class EncodingTest : EncodingTestBase
+	{
+		static CodePageTestInfo[] codepageTestInfos = new CodePageTestInfo[]
+		{
+			// FIXME: a lot of the tests fail because of different expectations of the test string (i.e. likely not a product bug), needs some rework of the tests
+			// new CodePageTestInfo { CodePage = 37,    IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 500,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 708,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 852,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 855,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 857,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 858,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 862,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 864,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 866,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 869,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 870,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 875,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1026,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1047,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1140,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1141,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1142,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1143,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1144,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1145,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1146,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1147,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1148,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 1149,  IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20273, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20277, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20278, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20280, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20284, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20285, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20290, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20297, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20420, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20424, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 20871, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			// new CodePageTestInfo { CodePage = 21025, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63, FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+		};
+	}
+}
+
diff --git a/mcs/class/I18N/West/I18N.West_test.dll.sources b/mcs/class/I18N/West/I18N.West_test.dll.sources
index b5fadfc4b95..bf39542632b 100644
--- a/mcs/class/I18N/West/I18N.West_test.dll.sources
+++ b/mcs/class/I18N/West/I18N.West_test.dll.sources
@@ -1 +1,3 @@
+../../EncodingTestBase.cs
+I18N.West.EncodingTest.cs
 I18N.West.Test.cs
diff --git a/mcs/class/I18N/West/Test/I18N.West.EncodingTest.cs b/mcs/class/I18N/West/Test/I18N.West.EncodingTest.cs
new file mode 100644
index 00000000000..2ebf01fe409
--- /dev/null
+++ b/mcs/class/I18N/West/Test/I18N.West.EncodingTest.cs
@@ -0,0 +1,61 @@
+//
+// I18N.West.EncodingTest.cs
+//
+// Author:
+//	Alexander Köplinger (alexander.koeplinger@xamarin.com)
+//
+// Copyright (C) 2017 Xamarin, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.Text;
+
+using NUnit.Framework;
+using NUnit.Framework.Constraints;
+
+using MonoTests.I18N;
+
+namespace MonoTests.I18N.West
+{
+	[TestFixture]
+	public class EncodingTest : EncodingTestBase
+	{
+		static CodePageTestInfo[] codepageTestInfos = new CodePageTestInfo[]
+		{
+			new CodePageTestInfo { CodePage = 437,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 53, InfinityReplacementChar = 236, FFReplacementChar = 65, A0Char = '\u00e1', A8Char = '\u00bf' },
+			new CodePageTestInfo { CodePage = 850,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00e1', A8Char = '\u00bf' },
+			new CodePageTestInfo { CodePage = 860,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 236, FFReplacementChar = 63, A0Char = '\u00e1', A8Char = '\u00bf' },
+			new CodePageTestInfo { CodePage = 861,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 236, FFReplacementChar = 63, A0Char = '\u00e1', A8Char = '\u00bf' },
+			new CodePageTestInfo { CodePage = 863,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 236, FFReplacementChar = 63, A0Char = '\u00a6', A8Char = '\u00ce' },
+			new CodePageTestInfo { CodePage = 865,   IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 236, FFReplacementChar = 63, A0Char = '\u00e1', A8Char = '\u00bf' },
+			new CodePageTestInfo { CodePage = 1250,  IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 1252,  IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 1253,  IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 10000, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 176, FFReplacementChar = 63, A0Char = '\u2020', A8Char = '\u00ae' },
+			new CodePageTestInfo { CodePage = 10079, IsBrowserDisplay = false, IsBrowserSave = false, IsMailNewsDisplay = false, IsMailNewsSave = false, SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 176, FFReplacementChar = 63, A0Char = '\u00dd', A8Char = '\u00ae' },
+			new CodePageTestInfo { CodePage = 28592, IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 28593, IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 28597, IsBrowserDisplay = true,  IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u00a8' },
+			new CodePageTestInfo { CodePage = 28605, IsBrowserDisplay = false, IsBrowserSave = true,  IsMailNewsDisplay = true,  IsMailNewsSave = true,  SuperscriptFiveReplacementChar = 63, InfinityReplacementChar = 63,  FFReplacementChar = 63, A0Char = '\u00a0', A8Char = '\u0161' }
+		};
+	}
+}