add repro for invalid header char

Author: flotwig

packages/server/test/e2e/6_visit_spec.coffee

@@ -46,6 +46,21 @@ onServer = (app) ->
     ## dont ever end this response
     res.type("html").write("foo\n")
 
+  ## https://github.com/cypress-io/cypress/issues/5602
+  app.get "/invalid-header-char", (req, res) ->
+    ## express/node may interfere if we just use res.setHeader
+    res.connection.write(
+        """
+        HTTP/1.1 200 OK
+        Content-Type: text/html
+        X-Foo: #{String.fromCharCode(0)}
+
+        foo
+        """
+    )
+
+    res.connection.end()
+
 describe "e2e visit", ->
   require("mocha-banner").register()
 

packages/server/test/support/fixtures/projects/e2e/cypress/integration/visit_spec.coffee

@@ -10,6 +10,11 @@ describe "visits", ->
   it "can load a local file with a huge amount of elements without timing out", ->
     cy.visit("/elements.html", {timeout: 5000})
 
+  ## https://github.com/cypress-io/cypress/issues/5602
+  it.only "can load a website which uses invalid HTTP header chars", ->
+    cy.visit("http://localhost:3434/invalid-header-char")
+    .contains('foo')
+
   context "issue #225: hash urls", ->
     rand = Math.random()