Fix encoding of VARINTs with value 0

lib/cql/protocol/cql_byte_buffer.rb

@@ -251,10 +251,14 @@ def append_long(n)
       def append_varint(n)
         num = n
         bytes = []
-        until num == 0
-          bytes << (num & 0xff)
-          num = num >> 8
-          break if num == -1
+        if num == 0
+          bytes << 0
+        else
+          until num == 0
+            bytes << (num & 0xff)
+            num = num >> 8
+            break if num == -1
+          end
         end
         append(bytes.reverse.pack(Formats::BYTES_FORMAT))
       end

spec/cql/protocol/cql_byte_buffer_spec.rb

@@ -810,6 +810,11 @@ module Protocol
       end
 
       describe '#append_varint' do
+        it 'encodes zero' do
+          buffer.append_varint(0)
+          buffer.should eql_bytes("\x00")
+        end
+
         it 'encodes a variable length integer' do
           buffer.append_varint(1231312312331283012830129382342342412123)
           buffer.should eql_bytes("\x03\x9EV \x15\f\x03\x9DK\x18\xCDI\\$?\a[")
@@ -843,6 +848,11 @@ module Protocol
           buffer.should eql_bytes("\x00\x00\x00\x12\r'\xFDI\xAD\x80f\x11g\xDCfV\xAA")
         end
 
+        it 'encodes a 0.0 BigDecimal' do
+          buffer.append_decimal(BigDecimal.new('0.0'))
+          buffer.should eql_bytes("\x00\x00\x00\x01\x00")
+        end
+
         it 'appends to the buffer' do
           buffer << "\x99"
           buffer.append_decimal(BigDecimal.new('1042342234234.123423435647768234'))