[ResolverSpec] Add spec covering the exclusion of subspec dependencies of…

[ResolverSpec] Add spec covering the exclusion of subspec dependencies of incompatible platforms when there's only one target platform

Done by using AFNetworking 2.4.1 and its UIKit subspec (iOS only) on an OS X platform

spec/unit/resolver_spec.rb

@@ -175,6 +175,23 @@ module Pod
         e.message.should.match(/platform .* not compatible/)
       end
 
+      it 'excludes subspec dependencies with incompatible platforms without' \
+        'raising' do
+        @podfile = Podfile.new do
+          platform :osx, '10.10'
+          pod 'AFNetworking', '2.4.1' # Has an 'AFNetworking/UIKit' iOS-only default subspec
+        end
+        resolver = Resolver.new(config.sandbox, @podfile, empty_graph, SourcesManager.all)
+        resolver.resolve.values.flatten.map(&:to_s).sort.should == [
+          "AFNetworking (2.4.1)",
+          "AFNetworking/NSURLConnection (2.4.1)",
+          "AFNetworking/NSURLSession (2.4.1)",
+          "AFNetworking/Reachability (2.4.1)",
+          "AFNetworking/Security (2.4.1)",
+          "AFNetworking/Serialization (2.4.1)",
+        ]
+      end
+
       it 'raises if unable to find a specification' do
         Specification.any_instance.stubs(:all_dependencies).returns([Dependency.new('Windows')])
         message = should.raise Informative do