[linter] Validate screenshots are valid

Closes #2010

CHANGELOG.md

@@ -20,6 +20,11 @@ To install or update CocoaPods see this [guide](http://docs.cocoapods.org/guides
   [Piet Brauer](https://github.com/pietbrauer)
   [Orta Therox](https://github.com/orta)
 
+* Validate the reachability of screenshot URLs in podspecs while linting a
+  specification.  
+  [Kyle Fuller](https://github.com/kylef)
+  [#2010](https://github.com/CocoaPods/CocoaPods/issues/2010)
+
 ## 0.31.1
 [CocoaPods](https://github.com/CocoaPods/CocoaPods/compare/0.31.1...0.31.0)
 • [CocoaPods-Core](https://github.com/CocoaPods/Core/compare/0.31.1...0.31.0)

lib/cocoapods/validator.rb

@@ -197,6 +197,7 @@ module Pod
     #
     def perform_extensive_analysis(spec)
       validate_homepage(spec)
+      validate_screenshots(spec)
 
       spec.available_platforms.each do |platform|
         UI.message "\n\n#{spec} - Analyzing on #{platform} platform.".green.reversed
@@ -222,22 +223,36 @@ module Pod
     attr_accessor :consumer
     attr_accessor :subspec_name
 
-    # Performs validations related to the `homepage` attribute.
+    # Performs validation of a URL
     #
-    def validate_homepage(spec)
+    def validate_url(url)
       require 'rest'
-      homepage = spec.homepage
-      return unless homepage
 
       begin
-        resp = ::REST.head(homepage)
+        resp = ::REST.head(url)
       rescue
-        warning "There was a problem validating the homepage."
+        warning "There was a problem validating the URL #{url}."
         resp = nil
       end
 
       if resp && !resp.success?
-        warning "The homepage is not reachable."
+        warning "The URL (#{url}) is not reachable."
+      end
+    end
+
+    # Performs validations related to the `homepage` attribute.
+    #
+    def validate_homepage(spec)
+      if spec.homepage
+        validate_url(spec.homepage)
+      end
+    end
+
+    # Performs validation related to the `screenshots` attribute.
+    #
+    def validate_screenshots(spec)
+      spec.screenshots.each do |screenshot|
+        validate_url(screenshot)
       end
     end
 

spec/unit/validator_spec.rb

@@ -99,14 +99,41 @@ module Pod
           WebMock::API.stub_request(:head, /not-found/).to_return(:status => 404)
           Specification.any_instance.stubs(:homepage).returns('http://banana-corp.local/not-found/')
           @sut.validate
-          @sut.results.map(&:to_s).first.should.match /The homepage is not reachable/
+          @sut.results.map(&:to_s).first.should.match /The URL (.*) is not reachable/
         end
 
         it "indicates if it was not able to validate the homepage" do
           WebMock::API.stub_request(:head, 'banana-corp.local').to_raise(SocketError)
           Specification.any_instance.stubs(:homepage).returns('http://banana-corp.local/')
           @sut.validate
-          @sut.results.map(&:to_s).first.should.match /There was a problem validating the homepage/
+          @sut.results.map(&:to_s).first.should.match /There was a problem validating the URL/
+        end
+      end
+
+      describe "Screenshot validation" do
+        require 'webmock'
+
+        before do
+          @sut = Validator.new(podspec_path)
+          @sut.stubs(:install_pod)
+          @sut.stubs(:build_pod)
+          @sut.stubs(:check_file_patterns)
+          @sut.stubs(:tear_down_validation_environment)
+          @sut.stubs(:validate_homepage)
+        end
+
+        it "checks if the screenshots are valid" do
+          WebMock::API.stub_request(:head, /banana-corp.local/).to_return(:status => 200)
+          Specification.any_instance.stubs(:screenshots).returns(['http://banana-corp.local/first.png', 'http://banana-corp.local/second.png'])
+          @sut.validate
+          @sut.results.should.be.empty?
+        end
+
+        it "should fail if any of the screenshots is not valid" do
+          WebMock::API.stub_request(:head, /not-found/).to_raise(SocketError)
+          Specification.any_instance.stubs(:screenshots).returns(['http://banana-corp.local/first.png', 'http://banana-corp.local/not-found/second.png'])
+          @sut.validate
+          @sut.results.map(&:to_s).first.should.match /There was a problem validating the URL/
         end
       end