Add matchers to verify form data

ghttp/handlers.go

diff --git a/ghttp/handlers.go b/ghttp/handlers.go
index c3b56a4..1e481f3 100644
--- a/ghttp/handlers.go
+++ b/ghttp/handlers.go
@@ -116,6 +116,27 @@
 	)
 }
 
+//VerifyForm returns a handler that verifies a request contains the specified form values.
+//
+//The request must contain *all* of the specified values, but it is allowed to have additional
+//form values beyond the passed in set.
+func VerifyForm(values url.Values) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		err := r.ParseForm()
+		Ω(err).ShouldNot(HaveOccurred())
+		for key, vals := range values {
+			Ω(r.Form[key]).Should(Equal(vals), "Form mismatch for key: %s", key)
+		}
+	}
+}
+
+//VerifyFormKV returns a handler that verifies a request contains a form key with the specified values.
+//
+//It is a convenience wrapper around `VerifyForm` that lets you avoid having to create a `url.Values` object.
+func VerifyFormKV(key string, values ...string) http.HandlerFunc {
+	return VerifyForm(url.Values{key: values})
+}
+
 func copyHeader(src http.Header, dst http.Header) {
 	for key, value := range src {
 		dst[key] = value

ghttp/test_server_test.go

diff --git a/ghttp/test_server_test.go b/ghttp/test_server_test.go
index 4d55b0f..3540ebf 100644
--- a/ghttp/test_server_test.go
+++ b/ghttp/test_server_test.go
@@ -503,6 +503,139 @@
 			})
 		})
 
+		Describe("VerifyForm", func() {
+			var formValues url.Values
+
+			BeforeEach(func() {
+				formValues = make(url.Values)
+				formValues.Add("users", "user1")
+				formValues.Add("users", "user2")
+				formValues.Add("group", "users")
+			})
+
+			Context("when encoded in the URL", func() {
+				BeforeEach(func() {
+					s.AppendHandlers(CombineHandlers(
+						VerifyRequest("GET", "/foo"),
+						VerifyForm(url.Values{
+							"users": []string{"user1", "user2"},
+							"group": []string{"users"},
+						}),
+					))
+				})
+
+				It("should verify form values", func() {
+					resp, err = http.Get(s.URL() + "/foo?" + formValues.Encode())
+					Ω(err).ShouldNot(HaveOccurred())
+				})
+
+				It("should ignore extra values", func() {
+					formValues.Add("extra", "value")
+					resp, err = http.Get(s.URL() + "/foo?" + formValues.Encode())
+					Ω(err).ShouldNot(HaveOccurred())
+				})
+
+				It("fail on missing values", func() {
+					formValues.Del("group")
+					failures := InterceptGomegaFailures(func() {
+						resp, err = http.Get(s.URL() + "/foo?" + formValues.Encode())
+					})
+					Ω(failures).Should(HaveLen(1))
+				})
+
+				It("fail on incorrect values", func() {
+					formValues.Set("group", "wheel")
+					failures := InterceptGomegaFailures(func() {
+						resp, err = http.Get(s.URL() + "/foo?" + formValues.Encode())
+					})
+					Ω(failures).Should(HaveLen(1))
+				})
+			})
+
+			Context("when present in the body", func() {
+				BeforeEach(func() {
+					s.AppendHandlers(CombineHandlers(
+						VerifyRequest("POST", "/foo"),
+						VerifyForm(url.Values{
+							"users": []string{"user1", "user2"},
+							"group": []string{"users"},
+						}),
+					))
+				})
+
+				It("should verify form values", func() {
+					resp, err = http.PostForm(s.URL()+"/foo", formValues)
+					Ω(err).ShouldNot(HaveOccurred())
+				})
+
+				It("should ignore extra values", func() {
+					formValues.Add("extra", "value")
+					resp, err = http.PostForm(s.URL()+"/foo", formValues)
+					Ω(err).ShouldNot(HaveOccurred())
+				})
+
+				It("fail on missing values", func() {
+					formValues.Del("group")
+					failures := InterceptGomegaFailures(func() {
+						resp, err = http.PostForm(s.URL()+"/foo", formValues)
+					})
+					Ω(failures).Should(HaveLen(1))
+				})
+
+				It("fail on incorrect values", func() {
+					formValues.Set("group", "wheel")
+					failures := InterceptGomegaFailures(func() {
+						resp, err = http.PostForm(s.URL()+"/foo", formValues)
+					})
+					Ω(failures).Should(HaveLen(1))
+				})
+			})
+		})
+
+		Describe("VerifyFormKV", func() {
+			Context("when encoded in the URL", func() {
+				BeforeEach(func() {
+					s.AppendHandlers(CombineHandlers(
+						VerifyRequest("GET", "/foo"),
+						VerifyFormKV("users", "user1", "user2"),
+					))
+				})
+
+				It("verifies the form value", func() {
+					resp, err = http.Get(s.URL() + "/foo?users=user1&users=user2")
+					Ω(err).ShouldNot(HaveOccurred())
+				})
+
+				It("verifies the form value", func() {
+					failures := InterceptGomegaFailures(func() {
+						resp, err = http.Get(s.URL() + "/foo?users=user1")
+					})
+					Ω(failures).Should(HaveLen(1))
+				})
+			})
+
+			Context("when present in the body", func() {
+				BeforeEach(func() {
+					s.AppendHandlers(CombineHandlers(
+						VerifyRequest("POST", "/foo"),
+						VerifyFormKV("users", "user1", "user2"),
+					))
+				})
+
+				It("verifies the form value", func() {
+					resp, err = http.PostForm(s.URL()+"/foo", url.Values{"users": []string{"user1", "user2"}})
+					Ω(err).ShouldNot(HaveOccurred())
+				})
+
+				It("verifies the form value", func() {
+					failures := InterceptGomegaFailures(func() {
+						resp, err = http.PostForm(s.URL()+"/foo", url.Values{"users": []string{"user1"}})
+					})
+					Ω(failures).Should(HaveLen(1))
+				})
+			})
+		})
+
 		Describe("RespondWith", func() {
 			Context("without headers", func() {
 				BeforeEach(func() {