feat: HaveHTTPBody matcher (#462)

matchers.go

@@ -427,6 +427,13 @@ func HaveHTTPStatus(expected interface{}) types.GomegaMatcher {
 	return &matchers.HaveHTTPStatusMatcher{Expected: expected}
 }
 
+// HaveHTTPBody matches if the body matches.
+// Actual must be either a *http.Response or *httptest.ResponseRecorder.
+// Expected must be either a string, []byte, or other matcher
+func HaveHTTPBody(expected interface{}) types.GomegaMatcher {
+	return &matchers.HaveHTTPBodyMatcher{Expected: expected}
+}
+
 //And succeeds only if all of the given matchers succeed.
 //The matchers are tried in order, and will fail-fast if one doesn't succeed.
 //  Expect("hi").To(And(HaveLen(2), Equal("hi"))

matchers/have_http_body_matcher.go

@@ -0,0 +1,101 @@
+package matchers
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+
+	"github.com/onsi/gomega/format"
+	"github.com/onsi/gomega/types"
+)
+
+type HaveHTTPBodyMatcher struct {
+	Expected   interface{}
+	cachedBody []byte
+}
+
+func (matcher *HaveHTTPBodyMatcher) Match(actual interface{}) (bool, error) {
+	body, err := matcher.body(actual)
+	if err != nil {
+		return false, err
+	}
+
+	switch e := matcher.Expected.(type) {
+	case string:
+		return (&EqualMatcher{Expected: e}).Match(string(body))
+	case []byte:
+		return (&EqualMatcher{Expected: e}).Match(body)
+	case types.GomegaMatcher:
+		return e.Match(body)
+	default:
+		return false, fmt.Errorf("HaveHTTPBody matcher expects string, []byte, or GomegaMatcher. Got:\n%s", format.Object(matcher.Expected, 1))
+	}
+}
+
+func (matcher *HaveHTTPBodyMatcher) FailureMessage(actual interface{}) (message string) {
+	body, err := matcher.body(actual)
+	if err != nil {
+		return fmt.Sprintf("failed to read body: %s", err)
+	}
+
+	switch e := matcher.Expected.(type) {
+	case string:
+		return (&EqualMatcher{Expected: e}).FailureMessage(string(body))
+	case []byte:
+		return (&EqualMatcher{Expected: e}).FailureMessage(body)
+	case types.GomegaMatcher:
+		return e.FailureMessage(body)
+	default:
+		return fmt.Sprintf("HaveHTTPBody matcher expects string, []byte, or GomegaMatcher. Got:\n%s", format.Object(matcher.Expected, 1))
+	}
+}
+
+func (matcher *HaveHTTPBodyMatcher) NegatedFailureMessage(actual interface{}) (message string) {
+	body, err := matcher.body(actual)
+	if err != nil {
+		return fmt.Sprintf("failed to read body: %s", err)
+	}
+
+	switch e := matcher.Expected.(type) {
+	case string:
+		return (&EqualMatcher{Expected: e}).NegatedFailureMessage(string(body))
+	case []byte:
+		return (&EqualMatcher{Expected: e}).NegatedFailureMessage(body)
+	case types.GomegaMatcher:
+		return e.NegatedFailureMessage(body)
+	default:
+		return fmt.Sprintf("HaveHTTPBody matcher expects string, []byte, or GomegaMatcher. Got:\n%s", format.Object(matcher.Expected, 1))
+	}
+}
+
+// body returns the body. It is cached because once we read it in Match()
+// the Reader is closed and it is not readable again in FailureMessage()
+// or NegatedFailureMessage()
+func (matcher *HaveHTTPBodyMatcher) body(actual interface{}) ([]byte, error) {
+	if matcher.cachedBody != nil {
+		return matcher.cachedBody, nil
+	}
+
+	body := func(a *http.Response) ([]byte, error) {
+		if a.Body != nil {
+			defer a.Body.Close()
+			var err error
+			matcher.cachedBody, err = ioutil.ReadAll(a.Body)
+			if err != nil {
+				return nil, fmt.Errorf("error reading response body: %w", err)
+			}
+		}
+		return matcher.cachedBody, nil
+	}
+
+	switch a := actual.(type) {
+	case *http.Response:
+		return body(a)
+	case *httptest.ResponseRecorder:
+		return body(a.Result())
+	default:
+		return nil, fmt.Errorf("HaveHTTPBody matcher expects *http.Response or *httptest.ResponseRecorder. Got:\n%s", format.Object(actual, 1))
+	}
+
+}

matchers/have_http_body_matcher_test.go

@@ -0,0 +1,187 @@
+package matchers_test
+
+import (
+	"bytes"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("HaveHTTPBody", func() {
+	When("ACTUAL is *http.Response", func() {
+		It("matches the body", func() {
+			const body = "this is the body"
+			resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(body))}
+			Expect(resp).To(HaveHTTPBody(body))
+		})
+
+		It("mismatches the body", func() {
+			const body = "this is the body"
+			resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(body))}
+			Expect(resp).NotTo(HaveHTTPBody("something else"))
+		})
+	})
+
+	When("ACTUAL is *httptest.ResponseRecorder", func() {
+		It("matches the body", func() {
+			const body = "this is the body"
+			resp := &httptest.ResponseRecorder{Body: bytes.NewBufferString(body)}
+			Expect(resp).To(HaveHTTPBody(body))
+		})
+
+		It("mismatches the body", func() {
+			const body = "this is the body"
+			resp := &httptest.ResponseRecorder{Body: bytes.NewBufferString(body)}
+			Expect(resp).NotTo(HaveHTTPBody("something else"))
+		})
+	})
+
+	When("ACTUAL is neither *http.Response nor *httptest.ResponseRecorder", func() {
+		It("errors", func() {
+			failures := InterceptGomegaFailures(func() {
+				Expect("foo").To(HaveHTTPBody("bar"))
+			})
+			Expect(failures).To(ConsistOf("HaveHTTPBody matcher expects *http.Response or *httptest.ResponseRecorder. Got:\n    <string>: foo"))
+		})
+	})
+
+	When("EXPECTED is []byte", func() {
+		It("matches the body", func() {
+			const body = "this is the body"
+			resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(body))}
+			Expect(resp).To(HaveHTTPBody([]byte(body)))
+		})
+
+		It("mismatches the body", func() {
+			const body = "this is the body"
+			resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(body))}
+			Expect(resp).NotTo(HaveHTTPBody([]byte("something else")))
+		})
+	})
+
+	When("EXPECTED is a submatcher", func() {
+		It("matches the body", func() {
+			resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(`{"some":"json"}`))}
+			Expect(resp).To(HaveHTTPBody(MatchJSON(`{ "some": "json" }`)))
+		})
+
+		It("mismatches the body", func() {
+			resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(`{"some":"json"}`))}
+			Expect(resp).NotTo(HaveHTTPBody(MatchJSON(`{ "something": "different" }`)))
+		})
+	})
+
+	When("EXPECTED is something else", func() {
+		It("errors", func() {
+			failures := InterceptGomegaFailures(func() {
+				resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader("body"))}
+				Expect(resp).To(HaveHTTPBody(map[int]bool{}))
+			})
+			Expect(failures).To(HaveLen(1))
+			Expect(failures[0]).To(Equal("HaveHTTPBody matcher expects string, []byte, or GomegaMatcher. Got:\n    <map[int]bool | len:0>: {}"))
+		})
+	})
+
+	Describe("FailureMessage", func() {
+		Context("EXPECTED is string", func() {
+			It("returns a match failure message", func() {
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader("this is the body"))}
+					Expect(resp).To(HaveHTTPBody("this is a different body"))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(Equal(`Expected
+    <string>: this is the body
+to equal
+    <string>: this is a different body`), failures[0])
+			})
+		})
+
+		Context("EXPECTED is []byte", func() {
+			It("returns a match failure message", func() {
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader("this is the body"))}
+					Expect(resp).To(HaveHTTPBody([]byte("this is a different body")))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(MatchRegexp(`^Expected
+    <\[\]uint8 \| len:\d+, cap:\d+>: this is the body
+to equal
+    <\[\]uint8 ]| len:\d+, cap:\d+>: this is a different body$`))
+			})
+		})
+
+		Context("EXPECTED is submatcher", func() {
+			It("returns a match failure message", func() {
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(`{"some":"json"}`))}
+					Expect(resp).To(HaveHTTPBody(MatchJSON(`{"other":"stuff"}`)))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(Equal(`Expected
+    <string>: {
+      "some": "json"
+    }
+to match JSON of
+    <string>: {
+      "other": "stuff"
+    }`))
+			})
+		})
+	})
+
+	Describe("NegatedFailureMessage", func() {
+		Context("EXPECTED is string", func() {
+			It("returns a negated failure message", func() {
+				const body = "this is the body"
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(body))}
+					Expect(resp).NotTo(HaveHTTPBody(body))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(Equal(`Expected
+    <string>: this is the body
+not to equal
+    <string>: this is the body`))
+			})
+		})
+
+		Context("EXPECTED is []byte", func() {
+			It("returns a match failure message", func() {
+				const body = "this is the body"
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(body))}
+					Expect(resp).NotTo(HaveHTTPBody([]byte(body)))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(MatchRegexp(`^Expected
+    <\[\]uint8 \| len:\d+, cap:\d+>: this is the body
+not to equal
+    <\[\]uint8 \| len:\d+, cap:\d+>: this is the body$`))
+			})
+		})
+
+		Context("EXPECTED is submatcher", func() {
+			It("returns a match failure message", func() {
+				const body = `{"some":"json"}`
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{Body: ioutil.NopCloser(strings.NewReader(body))}
+					Expect(resp).NotTo(HaveHTTPBody(MatchJSON(body)))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(Equal(`Expected
+    <string>: {
+      "some": "json"
+    }
+not to match JSON of
+    <string>: {
+      "some": "json"
+    }`))
+			})
+		})
+	})
+})