diff --git a/Library/Homebrew/test/test_cmd_testbot.rb b/Library/Homebrew/test/test_cmd_testbot.rb
new file mode 100644
index 0000000000..77a9b3df50
--- /dev/null
+++ b/Library/Homebrew/test/test_cmd_testbot.rb
@@ -0,0 +1,45 @@
+require "testing_env"
+require "dev-cmd/test-bot"
+
+class TestbotCommandTests < Homebrew::TestCase
+  def with_environment(partial_env)
+    old = ENV.to_hash
+    ENV.update partial_env
+    begin
+      yield
+    ensure
+      ENV.replace old
+    end
+  end
+
+  def test_resolve_test_tap
+    tap = Homebrew.resolve_test_tap
+    assert_nil tap, "Should return nil if no tap slug provided"
+
+    slug = "spam/homebrew-eggs"
+    url = "https://github.com/#{slug}.git"
+    environments = [
+      { "TRAVIS_REPO_SLUG" => slug },
+      { "UPSTREAM_BOT_PARAMS" => "--tap=#{slug}" },
+      { "UPSTREAM_BOT_PARAMS" => "--tap=spam/eggs" },
+      { "UPSTREAM_GIT_URL" => url },
+      { "GIT_URL" => url },
+    ]
+
+    predicate = proc do |message|
+      tap = Homebrew.resolve_test_tap
+      assert_kind_of Tap, tap, message
+      assert_equal tap.user, "spam", message
+      assert_equal tap.repo, "eggs", message
+    end
+
+    environments.each do |pair|
+      with_environment(pair) do
+        predicate.call pair.to_s
+      end
+    end
+
+    ARGV.expects(:value).with("tap").returns(slug)
+    predicate.call "ARGV"
+  end
+end