Merge pull request #275 from ryankinderman/master-stubbed-lazy-response

Adding support for lazy construction of responses from stubbed requests

lib/typhoeus.rb

@@ -73,13 +73,15 @@ def configure
   # @return [ Typhoeus::Expectation ] The expecatation.
   #
   # @see Typhoeus::Expectation
-  def stub(base_url, options = {})
+  def stub(base_url, options = {}, &block)
     expectation = Expectation.all.find{ |e| e.base_url == base_url && e.options == options }
-    return expectation if expectation
-
-    Expectation.new(base_url, options).tap do |new_expectation|
-      Expectation.all << new_expectation
+    if expectation.nil?
+      expectation = Expectation.new(base_url, options)
+      Expectation.all << expectation
     end
+
+    expectation.and_return &block unless block.nil?
+    expectation
   end
 
   # Add before callbacks.

lib/typhoeus/expectation.rb

@@ -14,6 +14,30 @@ module Typhoeus
   #   actual = Typhoeus.get("www.example.com")
   #   expected == actual
   #   #=> true
+  #
+  # @example Stub a request and get a lazily-constructed response containing data from actual widgets that exist in the system when the stubbed request is made.
+  #   Typhoeus.stub("www.example.com/widgets") do
+  #     actual_widgets = Widget.all
+  #     Typhoeus::Response.new(
+  #       :body => actual_widgets.inject([]) do |ids, widget|
+  #         ids << widget.id
+  #       end.join(",")
+  #     )
+  #   end
+  #
+  # @example Stub a request and get a lazily-constructed response in the format requested.
+  #   Typhoeus.stub("www.example.com") do |request|
+  #     accept = (request.options[:headers]||{})['Accept'] || "application/json"
+  #     format = accept.split(",").first
+  #     body_obj = { 'things' => [ { 'id' => 'foo' } ] }
+  #
+  #     Typhoeus::Response.new(
+  #       :headers => {
+  #         'Content-Type' => format
+  #       },
+  #       :body => SERIALIZERS[format].serialize(body_obj)
+  #     )
+  #   end
   class Expectation
 
     # @api private
@@ -47,15 +71,26 @@ def clear
         all.clear
       end
 
-      # Returns expecation matching the provided
-      # request.
+      # Returns stubbed response matching the
+      # provided request
       #
-      # @example Find expectation.
-      #   Typhoeus::Expectation.find_by(request)
+      # @example Find response
+      #   Typhoeus::Expectation.response_for(request)
       #
-      # @return [ Expectation ] The matching expectation.
+      # @return [ Typhoeus::Response ] The stubbed response from a
+      #   matching expectation, or nil if no matching expectation
+      #   is found.
       #
       # @api private
+      def response_for(request)
+        expectation = find_by(request)
+        return nil if expectation.nil?
+
+        expectation.response(request)
+      end
+
+      private
+
       def find_by(request)
         all.find do |expectation|
           expectation.matches?(request)
@@ -101,8 +136,8 @@ def stubbed_from(value)
     #   expectation.and_return(response)
     #
     # @return [ void ]
-    def and_return(response)
-      responses << response
+    def and_return(response=nil, &block)
+      responses << (response.nil? ? block : response)
     end
 
     # Checks wether this expectation matches
@@ -142,8 +177,11 @@ def responses
     # @return [ Response ] The response.
     #
     # @api private
-    def response
+    def response(request)
       response = responses.fetch(@response_counter, responses.last)
+      if response.respond_to?(:call)
+        response = response.call(request)
+      end
       @response_counter += 1
       response.mock = @from || true
       response

lib/typhoeus/hydra/stubbable.rb

@@ -15,8 +15,8 @@ module Stubbable
       # @example Add the request.
       #   hydra.add(request)
       def add(request)
-        if expectation = Expectation.find_by(request)
-          request.finish(expectation.response)
+        if response = Expectation.response_for(request)
+          request.finish(response)
         else
           super
         end

lib/typhoeus/request/stubbable.rb

@@ -17,8 +17,8 @@ module Stubbable
       #
       # @return [ Response ] The response.
       def run
-        if expectation = Expectation.find_by(self)
-          finish(expectation.response)
+        if response = Expectation.response_for(self)
+          finish(response)
         else
           super
         end

spec/typhoeus/expectation_spec.rb

@@ -47,13 +47,23 @@
     end
   end
 
-  describe ".find_by" do
+  describe ".response_for" do
     let(:request) { Typhoeus::Request.new("") }
+    let(:stubbed_response) { Typhoeus::Response.new }
 
-    it "returns a dummy when expectations not empty" do
+    it "finds a matching expectation and returns its next response" do
       Typhoeus::Expectation.all << expectation
       expectation.should_receive(:matches?).with(request).and_return(true)
-      expect(Typhoeus::Expectation.find_by(request)).to eq(expectation)
+      expectation.should_receive(:response).with(request).and_return(stubbed_response)
+
+      response = Typhoeus::Expectation.response_for(request)
+
+      expect(response).to be(stubbed_response)
+    end
+
+    it "returns nil if no matching expectation is found" do
+      response = Typhoeus::Expectation.response_for(request)
+      expect(response).to be(nil)
     end
   end
 
@@ -83,6 +93,14 @@
         expect(expectation.responses).to eq([1, 2])
       end
     end
+
+    context "when block" do
+      it "adds to responses" do
+        block = Proc.new {}
+        expectation.and_return &block
+        expect(expectation.responses).to eq([block])
+      end
+    end
   end
 
   describe "#responses" do
@@ -92,13 +110,32 @@
   end
 
   describe "#response" do
+    let(:request) { Typhoeus::Request.new("") }
+
     before { expectation.instance_variable_set(:@responses, responses) }
 
     context "when one response" do
-      let(:responses) { [Typhoeus::Response.new] }
+      context "is pre-constructed" do
+        let(:responses) { [Typhoeus::Response.new] }
+
+        it "returns response" do
+          expect(expectation.response(request)).to be(responses[0])
+        end
+      end
 
-      it "returns response" do
-        expect(expectation.response).to be(responses[0])
+      context "is lazily-constructed" do
+        def construct_response(request)
+          @request_from_response_construction = request
+          lazily_constructed_response
+        end
+
+        let(:lazily_constructed_response) { Typhoeus::Response.new }
+        let(:responses) { [ Proc.new { |request| construct_response(request) } ] }
+
+        it "returns response" do
+          expect(expectation.response(request)).to be(lazily_constructed_response)
+          expect(@request_from_response_construction).to be(request)
+        end
       end
     end
 
@@ -107,7 +144,7 @@
 
       it "returns one by one" do
         3.times do |i|
-          expect(expectation.response).to eq(responses[i])
+          expect(expectation.response(request)).to be(responses[i])
         end
       end
     end

spec/typhoeus/hydra/before_spec.rb

@@ -16,23 +16,23 @@
         context "when true" do
           it "calls super" do
             Typhoeus.before { true }
-            Typhoeus::Expectation.should_receive(:find_by)
+            Typhoeus::Expectation.should_receive(:response_for)
             hydra.add(request)
           end
         end
 
         context "when false" do
           it "doesn't call super" do
             Typhoeus.before { false }
-            Typhoeus::Expectation.should_receive(:find_by).never
+            Typhoeus::Expectation.should_receive(:response_for).never
             hydra.add(request)
           end
         end
 
         context "when response" do
           it "doesn't call super" do
             Typhoeus.before { Typhoeus::Response.new }
-            Typhoeus::Expectation.should_receive(:find_by).never
+            Typhoeus::Expectation.should_receive(:response_for).never
             hydra.add(request)
           end
         end
@@ -43,7 +43,7 @@
           before { 3.times { Typhoeus.before { |r| String.new(r.base_url) } } }
 
           it "calls super" do
-            Typhoeus::Expectation.should_receive(:find_by)
+            Typhoeus::Expectation.should_receive(:response_for)
             hydra.add(request)
           end
 
@@ -61,7 +61,7 @@
           end
 
           it "doesn't call super" do
-            Typhoeus::Expectation.should_receive(:find_by).never
+            Typhoeus::Expectation.should_receive(:response_for).never
             hydra.add(request)
           end
 
@@ -75,7 +75,7 @@
 
     context "when no before" do
       it "calls super" do
-        Typhoeus::Expectation.should_receive(:find_by)
+        Typhoeus::Expectation.should_receive(:response_for)
         hydra.add(request)
       end
     end

spec/typhoeus/hydra/stubbable_spec.rb

@@ -9,7 +9,7 @@
   before { Typhoeus.stub(base_url).and_return(response) }
 
   describe "#add" do
-    it "checks expactations" do
+    it "checks expectations" do
       hydra.add(request)
     end
 

spec/typhoeus/request/before_spec.rb

@@ -15,15 +15,15 @@
         context "when true" do
           it "calls super" do
             Typhoeus.before { true }
-            Typhoeus::Expectation.should_receive(:find_by)
+            Typhoeus::Expectation.should_receive(:response_for)
             request.run
           end
         end
 
         context "when false" do
           it "doesn't call super" do
             Typhoeus.before { false }
-            Typhoeus::Expectation.should_receive(:find_by).never
+            Typhoeus::Expectation.should_receive(:response_for).never
             request.run
           end
 
@@ -36,7 +36,7 @@
         context "when a response" do
           it "doesn't call super" do
             Typhoeus.before { Typhoeus::Response.new }
-            Typhoeus::Expectation.should_receive(:find_by).never
+            Typhoeus::Expectation.should_receive(:response_for).never
             request.run
           end
 
@@ -52,7 +52,7 @@
           before { 3.times { Typhoeus.before { |r| String.new(r.base_url) } } }
 
           it "calls super" do
-            Typhoeus::Expectation.should_receive(:find_by)
+            Typhoeus::Expectation.should_receive(:response_for)
             request.run
           end
 
@@ -70,7 +70,7 @@
           end
 
           it "doesn't call super" do
-            Typhoeus::Expectation.should_receive(:find_by).never
+            Typhoeus::Expectation.should_receive(:response_for).never
             request.run
           end
 
@@ -84,7 +84,7 @@
 
     context "when no before" do
       it "calls super" do
-        Typhoeus::Expectation.should_receive(:find_by)
+        Typhoeus::Expectation.should_receive(:response_for)
         request.run
       end
     end

spec/typhoeus/request/stubbable_spec.rb

@@ -7,8 +7,8 @@
 
   before { Typhoeus.stub(base_url).and_return(response) }
 
-  describe "#queue" do
-    it "checks expactations" do
+  describe "#run" do
+    it "checks expectations" do
       request.run
     end
 

spec/typhoeus_spec.rb

@@ -21,7 +21,22 @@
   describe ".stub" do
     let(:base_url) { "www.example.com" }
 
+    shared_examples "lazy response construction" do
+      it "calls the block to construct a response when a request matches the stub" do
+        expected_response = Typhoeus::Response.new
+        Typhoeus.stub(base_url) do |request|
+          expected_response
+        end
+
+        response = Typhoeus.get(base_url)
+
+        expect(response).to be(expected_response)
+      end
+    end
+
     context "when no similar expectation exists" do
+      include_examples "lazy response construction"
+
       it "returns expectation" do
         expect(Typhoeus.stub(base_url)).to be_a(Typhoeus::Expectation)
       end
@@ -33,6 +48,8 @@
     end
 
     context "when similar expectation exists" do
+      include_examples "lazy response construction"
+
       let(:expectation) { Typhoeus::Expectation.new(base_url) }
       before { Typhoeus::Expectation.all << expectation }