diff --git a/logstash-output-opentsdb.gemspec b/logstash-output-opentsdb.gemspec
index 10459c1..81ac75c 100644
--- a/logstash-output-opentsdb.gemspec
+++ b/logstash-output-opentsdb.gemspec
@@ -23,5 +23,6 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency "logstash-core-plugin-api", "~> 2.0"
 
   s.add_development_dependency 'logstash-devutils'
+  s.add_development_dependency 'logstash-codec-plain'
 end
 
diff --git a/spec/outputs/opentsdb_spec.rb b/spec/outputs/opentsdb_spec.rb
index 6bf5945..75cae98 100644
--- a/spec/outputs/opentsdb_spec.rb
+++ b/spec/outputs/opentsdb_spec.rb
@@ -1 +1,62 @@
-require "logstash/devutils/rspec/spec_helper"
+require 'logstash/devutils/rspec/spec_helper'
+require 'logstash/outputs/opentsdb'
+
+require_relative '../spec_helper'
+
+describe LogStash::Outputs::Opentsdb do
+
+  before do
+    subject.register
+    subject.receive event
+  end
+
+  subject { LogStash::Outputs::Opentsdb.new(config) }
+
+  context 'single metric, no tags' do
+    let(:config) do
+      {
+        'metrics' => ['metric_1', '%{val}']
+      }
+    end
+
+    let(:event) { LogStash::Event.new('val' => 123) }
+
+    it 'sends the correct opentsdb format' do
+      expect(subject.socket.pop).to match(/^put metric_1 \d+ 123 \n/)
+    end
+  end
+
+  context 'single metric, multiple tags' do
+    let(:config) do
+      {
+        'metrics' => ['metric_1', '%{val}', 'tag1', '%{tag1}', 'tag2', '%{tag2}']
+      }
+    end
+
+    let(:event) { LogStash::Event.new('val' => 123, 'tag1' => 'foo', 'tag2' => 'bar') }
+
+    it 'sends the correct opentsdb format' do
+      expect(subject.socket.pop).to match(/^put metric_1 \d+ 123 tag1=foo tag2=bar\n/)
+    end
+  end
+
+  context 'socket.puts fails with ECONNRESET' do
+    let(:config) do
+      {
+        'metrics' => ['metric_1', '%{val}']
+      }
+    end
+    let(:event) { LogStash::Event.new('val' => 123) }
+
+    before do
+      subject.register
+    end
+
+    it 'tries to reconnect' do
+      allow(subject.socket).to receive(:puts).and_raise(Errno::ECONNRESET)
+      expect(subject).to receive(:connect)
+
+      subject.receive event
+    end
+  end
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
new file mode 100644
index 0000000..f877d5b
--- /dev/null
+++ b/spec/spec_helper.rb
@@ -0,0 +1,10 @@
+require_relative 'support/server'
+
+class LogStash::Outputs::Opentsdb
+  attr_reader :socket
+
+  # Mock connect to return a fake server
+  def connect
+    @socket = Mocks::Server.new
+  end
+end
diff --git a/spec/support/server.rb b/spec/support/server.rb
new file mode 100644
index 0000000..002452c
--- /dev/null
+++ b/spec/support/server.rb
@@ -0,0 +1,29 @@
+module Mocks
+  class Server
+
+    def initialize
+      @queue = Array.new
+    end
+
+    def size
+      @queue.length
+    end
+
+    def pop
+      @queue.pop
+    end
+
+    def stop
+    end
+
+    def empty?
+      @queue.empty?
+    end
+
+    def puts(data)
+      data.split("\n").each do |line|
+        @queue << "#{line}\n"
+      end
+    end
+  end
+end