Added basic specs

.rspec

@@ -0,0 +1,4 @@
+-I lib
+--color
+--format doc
+spec

Gemfile

@@ -0,0 +1,7 @@
+source :rubygems
+
+gemspec
+
+group :test do
+  gem 'rspec'
+end

Gemfile.lock

@@ -0,0 +1,30 @@
+PATH
+  remote: .
+  specs:
+    multimeter (1.0.0.pre0-java)
+      json
+      metrics-core-jars
+
+GEM
+  remote: http://rubygems.org/
+  specs:
+    diff-lcs (1.1.3)
+    json (1.7.3-java)
+    metrics-core-jars (2.1.2-java)
+      slf4j-jars (~> 1)
+    rspec (2.11.0)
+      rspec-core (~> 2.11.0)
+      rspec-expectations (~> 2.11.0)
+      rspec-mocks (~> 2.11.0)
+    rspec-core (2.11.0)
+    rspec-expectations (2.11.1)
+      diff-lcs (~> 1.1.3)
+    rspec-mocks (2.11.0)
+    slf4j-jars (1.6.2-java)
+
+PLATFORMS
+  java
+
+DEPENDENCIES
+  multimeter!
+  rspec

lib/multimeter.rb

@@ -244,31 +244,42 @@ def each_metric
     end
 
     def get(name)
-      @registry.all_metrics[name]
+      @registry.all_metrics[create_name(name)]
     end
 
     def gauge(name, options={}, &block)
+      if get(name) && block_given?
+        raise ArgumentError, %(Cannot redeclare gauge #{name})
+      end
       @registry.new_gauge(create_name(name), ProcGauge.new(block))
     end
 
     def counter(name, options={})
-      @registry.new_counter(create_name(name))
+      error_translation do
+        @registry.new_counter(create_name(name))
+      end
     end
 
     def meter(name, options={})
-      event_type = (options[:event_type] || '').to_s
-      time_unit = TIME_UNITS[options[:time_unit] || :seconds]
-      @registry.new_meter(create_name(name), event_type, time_unit)
+      error_translation do
+        event_type = (options[:event_type] || '').to_s
+        time_unit = TIME_UNITS[options[:time_unit] || :seconds]
+        @registry.new_meter(create_name(name), event_type, time_unit)
+      end
     end
 
     def histogram(name, options={})
-      @registry.new_histogram(create_name(name), !!options[:biased])
+      error_translation do
+        @registry.new_histogram(create_name(name), !!options[:biased])
+      end
     end
 
     def timer(name, options={})
-      duration_unit = TIME_UNITS[options[:duration_unit] || :milliseconds]
-      rate_unit = TIME_UNITS[options[:rate_unit] || :seconds]
-      @registry.new_timer(create_name(name), duration_unit, rate_unit)
+      error_translation do
+        duration_unit = TIME_UNITS[options[:duration_unit] || :milliseconds]
+        rate_unit = TIME_UNITS[options[:rate_unit] || :seconds]
+        @registry.new_timer(create_name(name), duration_unit, rate_unit)
+      end
     end
 
     private
@@ -281,6 +292,14 @@ def timer(name, options={})
     def create_name(name)
       ::Yammer::Metrics::MetricName.new(@group, @type, name.to_s)
     end
+
+    def error_translation
+      begin
+        yield
+      rescue java.lang.ClassCastException => cce
+        raise ArgumentError, %(Cannot redeclare a metric as another type)
+      end
+    end
   end
 
   class ProcGauge < ::Yammer::Metrics::Gauge

multimeter.gemspec

@@ -17,6 +17,7 @@ Gem::Specification.new do |s|
   s.rubyforge_project = 'multimeter'
 
   s.add_dependency 'metrics-core-jars'
+  s.add_dependency 'json'
 
   s.files         = FileList['lib/**/*.rb'].to_a
   s.require_paths = %w[lib]

spec/multimeter/registry_spec.rb

@@ -0,0 +1,39 @@
+require_relative '../spec_helper'
+
+
+module Multimeter
+  describe Registry do
+    let :registry do
+      Multimeter.registry('a_group', 'some_type')
+    end
+
+    context 'when creating metrics' do
+      [:counter, :meter, :histogram, :timer].each do |metric_type|
+        it "##{metric_type} creates a new #{metric_type}" do
+          metric = registry.send(metric_type, :some_name)
+          metric.should_not be_nil
+        end
+      end
+
+      it '#gauge creates a gauge' do
+        registry.gauge(:some_name) { 42 }
+      end
+
+      it 'caches metric objects' do
+        registry.counter(:some_name).should equal(registry.counter(:some_name))
+      end
+
+      it 'raises an error when a gauge is redeclared, but not when it is accessed without a block' do
+        g1 = registry.gauge(:some_name) { 42 }
+        g2 = registry.gauge(:some_name)
+        g1.should equal(g2)
+        expect { registry.gauge(:some_name) { 43 } }.to raise_error(ArgumentError)
+      end
+
+      it 'raises an error if a metric is redeclared as another type' do
+        registry.counter(:some_name)
+        expect { registry.meter(:some_name) }.to raise_error(ArgumentError)
+      end
+    end
+  end
+end

spec/spec_helper.rb

@@ -0,0 +1 @@
+require 'multimeter'

spec/yammer/metrics_spec.rb

@@ -0,0 +1,80 @@
+require_relative '../spec_helper'
+
+
+module Yammer::Metrics
+  describe Yammer::Metrics do
+    let :registry do
+      Multimeter.registry('a_group', 'some_type')
+    end
+
+    describe Counter do
+      describe '#to_h' do
+        it 'returns a hash representation of the counter' do
+          c = registry.counter(:a_counter)
+          c.inc
+          c.to_h.should == {:count => 1}
+        end
+      end
+    end
+
+    describe Meter do
+      describe '#to_h' do
+        it 'returns a hash representation of the meter' do
+          m = registry.meter(:some_meter, :event_type => 'stuff')
+          m.mark
+          h = m.to_h
+          h[:event_type].should == 'stuff'
+          h[:count].should == 1
+          h[:mean_rate].should be_a(Numeric)
+          h[:one_minute_rate].should be_a(Numeric)
+          h[:five_minute_rate].should be_a(Numeric)
+          h[:fifteen_minute_rate].should be_a(Numeric)
+        end
+      end
+    end
+
+    describe Histogram do
+      it 'returns a hash representation of the histogram' do
+        hs = registry.histogram(:some_hist)
+        hs.update(4)
+        h = hs.to_h
+        h[:count].should == 1
+        h[:max].should be_a(Numeric)
+        h[:min].should be_a(Numeric)
+        h[:mean].should be_a(Numeric)
+        h[:std_dev].should be_a(Numeric)
+        h[:sum].should be_a(Numeric)
+      end
+    end
+
+    describe Timer do
+      describe '#to_h' do
+        it 'returns a hash representation of the timer' do
+          t = registry.timer(:some_timer)
+          t.measure { }
+          h = t.to_h
+          h[:event_type].should == 'calls'
+          h[:count].should == 1
+          h[:mean_rate].should be_a(Numeric)
+          h[:one_minute_rate].should be_a(Numeric)
+          h[:five_minute_rate].should be_a(Numeric)
+          h[:fifteen_minute_rate].should be_a(Numeric)
+          h[:max].should be_a(Numeric)
+          h[:min].should be_a(Numeric)
+          h[:mean].should be_a(Numeric)
+          h[:std_dev].should be_a(Numeric)
+          h[:sum].should be_a(Numeric)
+        end
+      end
+    end
+
+    describe Gauge do
+      describe '#to_h' do
+        it 'returns a hash representation of the gauge' do
+          g = registry.gauge(:some_gauge) { 42 }
+          g.to_h.should == {:value => 42}
+        end
+      end
+    end
+  end
+end