cypress-io
diff --git a/‎packages/driver/package.json
+1 b/‎packages/driver/package.json
+1
diff --git a/‎packages/driver/src/cy/commands/cookies.coffee
+31-3 b/‎packages/driver/src/cy/commands/cookies.coffee
+31-3
diff --git a/‎packages/driver/src/cypress/error_messages.coffee
+7 b/‎packages/driver/src/cypress/error_messages.coffee
+7
diff --git a/‎packages/driver/test/cypress/integration/commands/cookies_spec.coffee
+62-5 b/‎packages/driver/test/cypress/integration/commands/cookies_spec.coffee
+62-5
@@ -55,6 +55,7 @@
     "parse-domain": "2.0.0",
     "setimmediate": "1.0.5",
     "sinon": "3.3.0",
+    "strict-cookie-parser": "3.1.0",
     "text-mask-addons": "3.8.0",
     "underscore": "1.9.1",
     "underscore.string": "3.3.5",
 
@@ -1,4 +1,5 @@
 _ = require("lodash")
+cookieParser = require("strict-cookie-parser")
 Promise = require("bluebird")
 
 $dom = require("../../dom")
@@ -33,6 +34,10 @@ mergeDefaults = (obj) ->
   else
     merge(obj)
 
+validateCookieName = (cmd, name, onFail) ->
+  if cookieParser.isCookieName(name) isnt true
+    Cypress.utils.throwErrByPath("cookies.invalid_name", { args: { cmd, name }, onFail })
+
 module.exports = (Commands, Cypress, cy, state, config) ->
   automateCookies = (event, obj = {}, log, timeout) ->
     automate = ->
@@ -99,8 +104,12 @@ module.exports = (Commands, Cypress, cy, state, config) ->
             obj
         })
 
+      onFail = options._log
+
       if not _.isString(name)
-        $utils.throwErrByPath("getCookie.invalid_argument", { onFail: options._log })
+        $utils.throwErrByPath("getCookie.invalid_argument", { onFail })
+
+      validateCookieName('getCookie', name, onFail)
 
       automateCookies("get:cookie", {name: name}, options._log, options.timeout)
       .then (resp) ->
@@ -161,14 +170,29 @@ module.exports = (Commands, Cypress, cy, state, config) ->
             obj
         })
 
+      onFail = options._log
+
       if not _.isString(name) or not _.isString(value)
-        $utils.throwErrByPath("setCookie.invalid_arguments", { onFail: options._log })
+        Cypress.utils.throwErrByPath("setCookie.invalid_arguments", { onFail })
+
+      validateCookieName('setCookie', name, onFail)
+
+      if cookieParser.parseCookieValue(value) == null
+        Cypress.utils.throwErrByPath("setCookie.invalid_value", { args: { value }, onFail })
 
       automateCookies("set:cookie", cookie, options._log, options.timeout)
       .then (resp) ->
         options.cookie = resp
 
         return resp
+      .catch (err) ->
+        Cypress.utils.throwErrByPath("setCookie.backend_error", {
+          args: {
+            browserDisplayName: Cypress.browser.displayName,
+            errStack: err.stack
+          }
+          onFail
+        })
 
     clearCookie: (name, options = {}) ->
       _.defaults options, {
@@ -193,8 +217,12 @@ module.exports = (Commands, Cypress, cy, state, config) ->
             obj
         })
 
+      onFail = options._log
+
       if not _.isString(name)
-        $utils.throwErrByPath("clearCookie.invalid_argument", { onFail: options._log })
+        $utils.throwErrByPath("clearCookie.invalid_argument", { onFail })
+
+      validateCookieName('clearCookie', name, onFail)
 
       ## TODO: prevent clearing a cypress namespace
       automateCookies("clear:cookie", {name: name}, options._log, options.timeout)
 
@@ -141,6 +141,7 @@ module.exports = {
     length_option: "#{cmd('contains')} cannot be passed a length option because it will only ever return 1 element."
 
   cookies:
+    invalid_name: "#{cmd('{{cmd}}')} must be passed an RFC-6265-compliant cookie name. You passed:\n\n`{{name}}`"
     removed_method: """
       The Cypress.Cookies.{{method}}() method has been removed.
 
@@ -812,7 +813,13 @@ module.exports = {
     unavailable: "The XHR server is unavailable or missing. This should never happen and likely is a bug. Open an issue if you see this message."
 
   setCookie:
+    backend_error: """
+    #{cmd('setCookie')} had an unexpected error setting the requested cookie in {{browserDisplayName}}.
+
+    {{errStack}}
+    """
     invalid_arguments: "#{cmd('setCookie')} must be passed two string arguments for name and value."
+    invalid_value: "#{cmd('setCookie')} must be passed an RFC-6265-compliant cookie value. You passed:\n\n`{{value}}`"
 
   spread:
     invalid_type: "#{cmd('spread')} requires the existing subject be array-like."
 
@@ -292,6 +292,15 @@ describe "src/cy/commands/cookies", ->
 
         cy.getCookie(123)
 
+      it "throws an error if the cookie name is invalid", (done) ->
+        cy.on "fail", (err) =>
+          expect(err.message).to.include("cy.getCookie() must be passed an RFC-6265-compliant cookie name.")
+          expect(err.message).to.include('You passed:\n\n`m=m`')
+
+          done()
+
+        cy.getCookie("m=m")
+
     describe ".log", ->
       beforeEach ->
         cy.on "log:added", (attrs, log) =>
@@ -427,17 +436,16 @@ describe "src/cy/commands/cookies", ->
       it "logs once on error", (done) ->
         error = new Error("some err message")
         error.name = "foo"
-        error.stack = "stack"
 
         Cypress.automation.rejects(error)
 
         cy.on "fail", (err) =>
           lastLog = @lastLog
 
           expect(@logs.length).to.eq(1)
-          expect(lastLog.get("error").message).to.eq "some err message"
-          expect(lastLog.get("error").name).to.eq "foo"
-          expect(lastLog.get("error").stack).to.eq error.stack
+          expect(lastLog.get("error").message).to.include "some err message"
+          expect(lastLog.get("error").name).to.eq "CypressError"
+          expect(lastLog.get("error").stack).to.include error.stack
           done()
 
         cy.setCookie("foo", "bar")
@@ -453,7 +461,7 @@ describe "src/cy/commands/cookies", ->
           expect(lastLog.get("state")).to.eq("failed")
           expect(lastLog.get("name")).to.eq("setCookie")
           expect(lastLog.get("message")).to.eq("foo, bar")
-          expect(err.message).to.eq("cy.setCookie() timed out waiting '50ms' to complete.")
+          expect(err.message).to.include("cy.setCookie() timed out waiting '50ms' to complete.")
           done()
 
         cy.setCookie("foo", "bar", {timeout: 50})
@@ -480,6 +488,46 @@ describe "src/cy/commands/cookies", ->
 
         cy.setCookie("foo", 123)
 
+      context "when setting an invalid cookie", ->
+        it "throws an error if the cookie name is invalid", (done) ->
+          cy.on "fail", (err) =>
+            expect(err.message).to.include("cy.setCookie() must be passed an RFC-6265-compliant cookie name.")
+            expect(err.message).to.include('You passed:\n\n`m=m`')
+
+            done()
+
+          ## cookie names may not contain =
+          ## https://stackoverflow.com/a/6109881/3474615
+          cy.setCookie("m=m", "foo")
+
+        it "throws an error if the cookie value is invalid", (done) ->
+          cy.on "fail", (err) =>
+            expect(err.message).to.include('must be passed an RFC-6265-compliant cookie value.')
+            expect(err.message).to.include('You passed:\n\n` bar`')
+
+            done()
+
+          ## cookies may not contain unquoted whitespace
+          cy.setCookie("foo", " bar")
+
+        it "throws an error if the backend responds with an error", (done) ->
+          cy.on "fail", (err) =>
+            expect(skipErrStub).to.be.calledOnce
+            expect(errStub).to.be.calledTwice
+            expect(err.message).to.contain('unexpected error setting the requested cookie')
+            done()
+
+          errStub = cy.stub(Cypress.utils, "throwErrByPath")
+          errStub.callThrough()
+
+          ## stub cookie validation so this invalid cookie can make it to the backend
+          skipErrStub = errStub
+          .withArgs("setCookie.invalid_value")
+          .returns()
+
+          ## browser backend should yell since this is invalid
+          cy.setCookie("foo", " bar")
+
     describe ".log", ->
       beforeEach ->
         cy.on "log:added", (attrs, log) =>
@@ -624,6 +672,15 @@ describe "src/cy/commands/cookies", ->
 
         cy.clearCookie(123)
 
+      it "throws an error if the cookie name is invalid", (done) ->
+        cy.on "fail", (err) =>
+          expect(err.message).to.include("cy.clearCookie() must be passed an RFC-6265-compliant cookie name.")
+          expect(err.message).to.include('You passed:\n\n`m=m`')
+
+          done()
+
+        cy.clearCookie("m=m")
+
     describe ".log", ->
       beforeEach ->
         cy.on "log:added", (attrs, log) =>