diff --git a/lib/rack/test.rb b/lib/rack/test.rb
index bd248378..c5be79b1 100644
--- a/lib/rack/test.rb
+++ b/lib/rack/test.rb
@@ -242,6 +242,7 @@ def env_for(path, env)
       def process_request(uri, env)
         uri = URI.parse(uri)
         uri.host ||= @default_host
+        uri.scheme ||= "https" if env["HTTPS"] == "on"
 
         @rack_mock_session.request(uri, env)
 
diff --git a/spec/rack/test/cookie_spec.rb b/spec/rack/test/cookie_spec.rb
index ba69b0ac..0b8a623f 100644
--- a/spec/rack/test/cookie_spec.rb
+++ b/spec/rack/test/cookie_spec.rb
@@ -138,6 +138,16 @@
       expect(rack_mock_session.cookie_jar['secure-cookie']).to eq('set')
     end
 
+    it "supports secure cookies when enabling SSL via env" do
+      get "//example.com/cookies/set-secure", { "value" => "set" }, "HTTPS" => "on"
+      get "//example.com/cookies/show", nil, "HTTPS" => "off"
+      check expect(last_request.cookies).to eq({})
+
+      get "//example.com/cookies/show", nil, "HTTPS" => "on"
+      expect(last_request.cookies).to eq({ "secure-cookie" => "set" })
+      expect(rack_mock_session.cookie_jar['secure-cookie']).to eq('set')
+    end
+
     it "keeps separate cookie jars for different domains" do
       get "http://example.com/cookies/set", "value" => "example"
       get "http://example.com/cookies/show"