DependencyCollector: return created dep from #add

Library/Homebrew/dependency_collector.rb

@@ -26,16 +26,23 @@ class DependencyCollector
     @requirements = ComparableSet.new
   end
 
-  def add spec
-    tag = nil
-    spec, tag = spec.shift if spec.is_a? Hash
+  def add(spec)
+    case dep = build(spec)
+    when Dependency
+      @deps << dep
+    when Requirement
+      @requirements << dep
+    end
+    dep
+  end
 
-    dep = parse_spec(spec, tag)
-    # Some symbol specs are conditional, and resolve to nil if there is no
-    # dependency needed for the current platform.
-    return if dep.nil?
-    # Add dep to the correct bucket
-    (dep.is_a?(Requirement) ? @requirements : @deps) << dep
+  def build(spec)
+    spec, tag = case spec
+                when Hash then spec.shift
+                else spec
+                end
+
+    parse_spec(spec, tag)
   end
 
 private

Library/Homebrew/test/test_dependency_collector.rb

@@ -24,6 +24,11 @@ class DependencyCollectorTests < Test::Unit::TestCase
     assert_equal 2, @d.find_dependency('bar').tags.length
   end
 
+  def test_add_returns_created_dep
+    ret = @d.add 'foo'
+    assert_equal Dependency.new('foo'), ret
+  end
+
   def test_dependency_tags
     assert Dependency.new('foo', :build).build?
     assert Dependency.new('foo', [:build, :optional]).optional?