test_dependency: add failing option names test.

This test will obviously fail but it does mark that the option names
are not being merged correctly.

Library/Homebrew/test/test_dependency.rb

@@ -39,6 +39,25 @@ class DependencyTests < Homebrew::TestCase
     assert_equal [:build, "bar"], dep.tags
   end
 
+  def test_merge_repeats
+    dep = Dependency.new("foo", [:build], nil, "foo")
+    dep2 = Dependency.new("foo", ["bar"], nil, "foo2")
+    dep3 = Dependency.new("xyz", ["abc"], nil, "foo")
+    merged = Dependency.merge_repeats([dep, dep2, dep3])
+    assert_equal 2, merged.length
+    assert_equal Dependency, merged.first.class
+
+    foo_named_dep = merged.find {|d| d.name == "foo"}
+    assert_equal [:build, "bar"], foo_named_dep.tags
+    assert_includes foo_named_dep.option_name, "foo"
+    assert_includes foo_named_dep.option_name, "foo2"
+
+    xyz_named_dep = merged.find {|d| d.name == "xyz"}
+    assert_equal ["abc"], xyz_named_dep.tags
+    assert_includes xyz_named_dep.option_name, "foo"
+    refute_includes xyz_named_dep.option_name, "foo2"
+  end
+
   def test_equality
     foo1 = Dependency.new("foo")
     foo2 = Dependency.new("foo")