diff --git a/Library/Homebrew/test/test_descriptions.rb b/Library/Homebrew/test/test_descriptions.rb
new file mode 100644
index 0000000000..de38fdbd13
--- /dev/null
+++ b/Library/Homebrew/test/test_descriptions.rb
@@ -0,0 +1,45 @@
+require "testing_env"
+require "descriptions"
+
+class DescriptionsTest < Homebrew::TestCase
+  def setup
+    @descriptions_hash = {}
+    @descriptions = Descriptions.new(@descriptions_hash)
+
+    @old_stdout = $stdout
+    $stdout = StringIO.new
+  end
+
+  def teardown
+    $stdout = @old_stdout
+  end
+
+  def test_single_core_formula
+    @descriptions_hash["homebrew/core/foo"] = "Core foo"
+    @descriptions.print
+    assert_equal "foo: Core foo", $stdout.string.chomp
+  end
+
+  def test_single_external_formula
+    @descriptions_hash["somedev/external/foo"] = "External foo"
+    @descriptions.print
+    assert_equal "foo: External foo", $stdout.string.chomp
+  end
+
+  def test_even_dupes
+    @descriptions_hash["homebrew/core/foo"] = "Core foo"
+    @descriptions_hash["somedev/external/foo"] = "External foo"
+    @descriptions.print
+    assert_equal "homebrew/core/foo: Core foo\nsomedev/external/foo: External foo",
+                 $stdout.string.chomp
+  end
+
+  def test_odd_dupes
+    @descriptions_hash["homebrew/core/foo"] = "Core foo"
+    @descriptions_hash["somedev/external/foo"] = "External foo"
+    @descriptions_hash["otherdev/external/foo"] = "Other external foo"
+    @descriptions.print
+    assert_equal "homebrew/core/foo: Core foo\notherdev/external/foo: Other external foo\nsomedev/external/foo: External foo",
+                 $stdout.string.chomp
+  end
+end