1 files changed, 46 insertions, 0 deletions
diff --git a/activesupport/test/string_inquirer_test.rb b/activesupport/test/string_inquirer_test.rb
new file mode 100644
index 0000000000..09726b144a
--- /dev/null
+++ b/activesupport/test/string_inquirer_test.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+class StringInquirerTest < ActiveSupport::TestCase
+  def setup
+    @string_inquirer = ActiveSupport::StringInquirer.new("production")
+  end
+
+  def test_match
+    assert_predicate @string_inquirer, :production?
+  end
+
+  def test_miss
+    assert_not_predicate @string_inquirer, :development?
+  end
+
+  def test_missing_question_mark
+    assert_raise(NoMethodError) { @string_inquirer.production }
+  end
+
+  def test_respond_to
+    assert_respond_to @string_inquirer, :development?
+  end
+
+  def test_respond_to_fallback_to_string_respond_to
+    String.class_eval do
+      def respond_to_missing?(name, include_private = false)
+        (name == :bar) || super
+      end
+    end
+    str = ActiveSupport::StringInquirer.new("hello")
+
+    assert_respond_to str, :are_you_ready?
+    assert_respond_to str, :bar
+    assert_not_respond_to str, :nope
+
+  ensure
+    String.class_eval do
+      undef_method :respond_to_missing?
+      def respond_to_missing?(name, include_private = false)
+        super
+      end
+    end
+  end
+end