Implement GetChar. Fixes #456

Author: bgrainger

src/MySqlConnector/Core/Row.cs

@@ -112,7 +112,11 @@ public long GetBytes(int ordinal, long dataOffset, byte[] buffer, int bufferOffs
 			return lengthToCopy;
 		}
 
-		public char GetChar(int ordinal) => (char) GetValue(ordinal);
+		public char GetChar(int ordinal)
+		{
+			var stringValue = (string) GetValue(ordinal);
+			return stringValue.Length > 0 ? stringValue[0] : throw new InvalidCastException();
+		}
 
 		public long GetChars(int ordinal, long dataOffset, char[] buffer, int bufferOffset, int length)
 		{

tests/SideBySide/DataTypes.cs

@@ -347,6 +347,34 @@ public void QueryGuid(string column, string dataTypeName, object[] expected)
 			DoQuery<GetGuidWhenNullException>("strings", column, dataTypeName, expected, reader => reader.GetGuid(0));
 		}
 
+		[Theory]
+		[InlineData("utf8", new[] {null, "", "ASCII", "Ũńıċōđĕ", c_251ByteString})]
+		[InlineData("cp1251", new[] { null, "", "ASCII", "АБВГабвг", c_251ByteString })]
+		public void QueryChar(string column, string[] expected)
+		{
+			using (var cmd = m_database.Connection.CreateCommand())
+			{
+				cmd.CommandText = $@"select `{column}` from datatypes_strings order by rowid;";
+				using (var reader = cmd.ExecuteReader())
+				{
+					for (var i = 0; i < expected.Length; i++)
+					{
+						Assert.True(reader.Read());
+						if (expected[i] == null)
+							Assert.True(reader.IsDBNull(0));
+						else if (expected[i].Length == 0)
+#if BASELINE
+							Assert.Throws<IndexOutOfRangeException>(() => reader.GetChar(0));
+#else
+							Assert.Throws<InvalidCastException>(() => reader.GetChar(0));
+#endif
+						else
+							Assert.Equal(expected[i][0], reader.GetChar(0));
+					}
+				}
+			}
+		}
+
 		[Theory]
 		[InlineData(false)]
 		[InlineData(true)]