如何测试Rails缓存功能 [英] how can I test rails cache feature
问题描述
这是我的Tag模型,我不知道如何测试Rails.cache功能。
This is my Tag model and I don't know how can I test Rails.cache feature.
class Tag < ActiveRecord::Base
class << self
def all_cached
Rails.cache.fetch("tags.all", :expires_in => 3.hours) do
Tag.order('name asc').to_a
end
end
def find_cached(id)
Rails.cache.fetch("tags/#{id}", :expires_in => 3.hours) do
Tag.find(id)
end
end
end
attr_accessible :name
has_friendly_id :name, :use_slug => true, :approximate_ascii => true
has_many :taggings #, :dependent => :destroy
has_many :projects, :through => :taggings
end
您知道如何对其进行测试吗?
Do you know how can it will be tested ?
推荐答案
首先,您不应该真正在测试框架。 Rails的缓存测试表面上可以满足您的要求。也就是说,请参见此答案,以获取一些帮助用。然后,您的测试将类似于:
Well, first, you shouldn't really be testing the framework. Rails' caching tests ostensibly cover that for you. That said, see this answer for a little helper you can use. Your tests would then look something like:
describe Tag do
describe "::all_cached" do
around {|ex| with_caching { ex.run } }
before { Rails.cache.clear }
context "given that the cache is unpopulated" do
it "does a database lookup" do
Tag.should_receive(:order).once.and_return(["tag"])
Tag.all_cached.should == ["tag"]
end
end
context "given that the cache is populated" do
let!(:first_hit) { Tag.all_cached }
it "does a cache lookup" do
before do
Tag.should_not_receive(:order)
Tag.all_cached.should == first_hit
end
end
end
end
end
这实际上并不检查缓存机制-只是 #fetch
块不被调用。它很脆弱,并且与提取块的实现紧密相关,因此请当心,因为它将成为维护债务。
This doesn't actually check the caching mechanism - just that the #fetch
block isn't invoked. It's brittle and tied to the implementation of the fetch block, so beware that as it will become maintenance debt.
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