[Analyzer] Don't validate platform for podless targets

When using the '--no-integrate' option, it's not required to check that
the `platform` is specified if the target doesn't have any declared
dependencies.

Fixes #3151

lib/cocoapods/installer/analyzer.rb

@@ -255,7 +255,7 @@ module Pod
           target.client_root = config.installation_root
           target.user_target_uuids = []
           target.user_build_configurations = target_definition.build_configurations || { 'Release' => :release, 'Debug' => :debug }
-          if target_definition.platform.name == :osx
+          if target_definition.platform && target_definition.platform.name == :osx
             target.archs = '$(ARCHS_STANDARD_64_BIT)'
           end
         end
@@ -636,7 +636,7 @@ module Pod
       def verify_platforms_specified!
         unless config.integrate_targets?
           podfile.target_definition_list.each do |target_definition|
-            unless target_definition.platform
+            if target_definition.dependencies.size > 0 && target_definition.platform.nil?
               raise Informative, 'It is necessary to specify the platform in the Podfile if not integrating.'
             end
           end

spec/unit/installer/analyzer_spec.rb

@@ -212,6 +212,43 @@ module Pod
         target.platform.to_s.should == 'iOS 6.0'
       end
 
+      describe 'no-integrate platform validation' do
+        before do
+          repos = [fixture('spec-repos/test_repo')]
+          aggregate = Pod::Source::Aggregate.new(repos)
+          Pod::SourcesManager.stubs(:aggregate).returns(aggregate)
+          aggregate.sources.first.stubs(:url).returns(SpecHelper.test_repo_url)
+          config.integrate_targets = false
+        end
+
+        it 'does not require a platform for a podless target' do
+          podfile = Pod::Podfile.new do
+            source SpecHelper.test_repo_url
+            xcodeproj 'SampleProject/SampleProject'
+            target 'TestRunner' do
+              platform :osx
+              pod 'monkey'
+            end
+          end
+
+          analyzer = Pod::Installer::Analyzer.new(config.sandbox, podfile)
+          lambda { analyzer.analyze }.should.not.raise
+        end
+
+        it 'raises if a target with pods does not specify a platform' do
+          podfile = Pod::Podfile.new do
+            source SpecHelper.test_repo_url
+            xcodeproj 'SampleProject/SampleProject'
+            target 'TestRunner' do
+              pod 'monkey'
+            end
+          end
+
+          analyzer = Pod::Installer::Analyzer.new(config.sandbox, podfile)
+          lambda { analyzer.analyze }.should.raise Informative
+        end
+      end
+
       it 'returns all the configurations the user has in any of its projects and/or targets' do
         target_definition = @analyzer.podfile.target_definition_list.first
         target_definition.stubs(:build_configurations).returns('AdHoc' => :test)