```ruby
require 'spec_helper'
require 'riak-shim/store'

describe Riak::Shim::Store do
  let(:store) { Riak::Shim::Store.new }


  describe '#config_location' do
    it 'keeps a path of the database config file' do
      path = store.config_location
      path.should_not be_nil
    end
  end

  context 'with test config' do
    before do
      tmpdir = Dir.tmpdir
      FileUtils.cp('./spec/support/database.yml', tmpdir)
      store.stub(:config_location).and_return("#{tmpdir}/database.yml")
    end

    describe '#read_config' do
      it 'reads yaml from config_location' do
        store.read_config.should == DB_CONFIG
      end
    end

    describe '#config' do
      context 'with RACK_ENV=test' do
        before do
          @stashed_rack_env = ENV['RACK_ENV']
          ENV['RACK_ENV'] = 'test'
        end

        after do
          ENV['RACK_ENV'] = @stashed_rack_env
        end

        it "says prefix is test_" do
          store.config['bucket_prefix'].should == 'test_'
        end
      end
    end

    describe '#bucket_prefix' do
      it 'uses the prefix from the config' do
        store.bucket_prefix.should == 'test_'
      end
    end
  end
end
```

Add test to demonstrate default configuration not being read.
user
```ruby
require 'spec_helper'
require 'riak-shim/store'

describe Riak::Shim::Store do
  let(:store) { Riak::Shim::Store.new }


  describe '#config_location' do
    it 'keeps a path of the database config file' do
      path = store.config_location
      path.should_not be_nil
    end
  end

  context 'with test config' do
    before do
      tmpdir = Dir.tmpdir
      FileUtils.cp('./spec/support/database.yml', tmpdir)
      store.stub(:config_location).and_return("#{tmpdir}/database.yml")
    end

    describe '#read_config' do
      it 'reads yaml from config_location' do
        store.read_config.should == DB_CONFIG
      end
    end

    describe 'default config' do
      context 'with RACK_ENV not explicitly configured in database.yml' do
        before do
          @stashed_rack_env = ENV['RACK_ENV']
          ENV['RACK_ENV'] = 'production'
        end

        after do
          ENV['RACK_ENV'] = @stashed_rack_env
        end

        it "says prefix is test_" do
          store.config['http_port'].should == 8098
        end
      end
    end

    describe '#config' do
      context 'with RACK_ENV=test' do
        before do
          @stashed_rack_env = ENV['RACK_ENV']
          ENV['RACK_ENV'] = 'test'
        end

        after do
          ENV['RACK_ENV'] = @stashed_rack_env
        end

        it "says prefix is test_" do
          store.config['bucket_prefix'].should == 'test_'
        end
      end
    end

    describe '#bucket_prefix' do
      it 'uses the prefix from the config' do
        store.bucket_prefix.should == 'test_'
      end
    end
  end
end
```
assistant