feat: HaveHTTPHeaderWithValue() matcher (#463)

Co-authored-by: Onsi Fakhouri <onsijoe@gmail.com>

matchers.go

@@ -427,6 +427,17 @@ func HaveHTTPStatus(expected interface{}) types.GomegaMatcher {
 	return &matchers.HaveHTTPStatusMatcher{Expected: expected}
 }
 
+// HaveHTTPHeaderWithValue succeeds if the header is found and the value matches.
+// Actual must be either a *http.Response or *httptest.ResponseRecorder.
+// Expected must be a string header name, followed by a header value which
+// can be a string, or another matcher.
+func HaveHTTPHeaderWithValue(header string, value interface{}) types.GomegaMatcher {
+	return &matchers.HaveHTTPHeaderWithValueMatcher{
+		Header: header,
+		Value:  value,
+	}
+}
+
 // 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

matchers/have_http_header_with_value_matcher.go

@@ -0,0 +1,81 @@
+package matchers
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+
+	"github.com/onsi/gomega/format"
+	"github.com/onsi/gomega/types"
+)
+
+type HaveHTTPHeaderWithValueMatcher struct {
+	Header string
+	Value  interface{}
+}
+
+func (matcher *HaveHTTPHeaderWithValueMatcher) Match(actual interface{}) (success bool, err error) {
+	headerValue, err := matcher.extractHeader(actual)
+	if err != nil {
+		return false, err
+	}
+
+	headerMatcher, err := matcher.getSubMatcher()
+	if err != nil {
+		return false, err
+	}
+
+	return headerMatcher.Match(headerValue)
+}
+
+func (matcher *HaveHTTPHeaderWithValueMatcher) FailureMessage(actual interface{}) string {
+	headerValue, err := matcher.extractHeader(actual)
+	if err != nil {
+		panic(err) // protected by Match()
+	}
+
+	headerMatcher, err := matcher.getSubMatcher()
+	if err != nil {
+		panic(err) // protected by Match()
+	}
+
+	diff := format.IndentString(headerMatcher.FailureMessage(headerValue), 1)
+	return fmt.Sprintf("HTTP header %q:\n%s", matcher.Header, diff)
+}
+
+func (matcher *HaveHTTPHeaderWithValueMatcher) NegatedFailureMessage(actual interface{}) (message string) {
+	headerValue, err := matcher.extractHeader(actual)
+	if err != nil {
+		panic(err) // protected by Match()
+	}
+
+	headerMatcher, err := matcher.getSubMatcher()
+	if err != nil {
+		panic(err) // protected by Match()
+	}
+
+	diff := format.IndentString(headerMatcher.NegatedFailureMessage(headerValue), 1)
+	return fmt.Sprintf("HTTP header %q:\n%s", matcher.Header, diff)
+}
+
+func (matcher *HaveHTTPHeaderWithValueMatcher) getSubMatcher() (types.GomegaMatcher, error) {
+	switch m := matcher.Value.(type) {
+	case string:
+		return &EqualMatcher{Expected: matcher.Value}, nil
+	case types.GomegaMatcher:
+		return m, nil
+	default:
+		return nil, fmt.Errorf("HaveHTTPHeaderWithValue matcher must be passed a string or a GomegaMatcher. Got:\n%s", format.Object(matcher.Value, 1))
+	}
+}
+
+func (matcher *HaveHTTPHeaderWithValueMatcher) extractHeader(actual interface{}) (string, error) {
+	switch r := actual.(type) {
+	case *http.Response:
+		return r.Header.Get(matcher.Header), nil
+	case *httptest.ResponseRecorder:
+		return r.Result().Header.Get(matcher.Header), nil
+	default:
+		return "", fmt.Errorf("HaveHTTPHeaderWithValue matcher expects *http.Response or *httptest.ResponseRecorder. Got:\n%s", format.Object(actual, 1))
+	}
+}

matchers/have_http_header_with_value_matcher_test.go

@@ -0,0 +1,161 @@
+package matchers_test
+
+import (
+	"net/http"
+	"net/http/httptest"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("HaveHTTPHeader", func() {
+	It("can match an HTTP header", func() {
+		resp := &http.Response{}
+		resp.Header = make(http.Header)
+		resp.Header.Add("fake-header", "fake value")
+		Expect(resp).To(HaveHTTPHeaderWithValue("fake-header", "fake value"))
+	})
+
+	It("can mismatch an HTTP header", func() {
+		resp := &http.Response{}
+		resp.Header = make(http.Header)
+		resp.Header.Add("fake-header", "fake value")
+		Expect(resp).NotTo(HaveHTTPHeaderWithValue("other-header", "fake value"))
+		Expect(resp).NotTo(HaveHTTPHeaderWithValue("fake-header", "other value"))
+	})
+
+	When("the header is set more than once", func() {
+		It("matches the first value and not the second", func() {
+			resp := &http.Response{}
+			resp.Header = make(http.Header)
+			resp.Header.Add("fake-header", "fake value1")
+			resp.Header.Add("fake-header", "fake value2")
+			Expect(resp).To(HaveHTTPHeaderWithValue("fake-header", "fake value1"))
+			Expect(resp).NotTo(HaveHTTPHeaderWithValue("fake-header", "fake value2"))
+		})
+	})
+
+	When("ACTUAL is *httptest.ResponseRecorder", func() {
+		It("can match an HTTP header", func() {
+			resp := &httptest.ResponseRecorder{}
+			resp.Header().Add("fake-header", "fake value")
+			Expect(resp).To(HaveHTTPHeaderWithValue("fake-header", "fake value"))
+		})
+
+		It("can mismatch an HTTP header", func() {
+			resp := &httptest.ResponseRecorder{}
+			resp.Header().Add("fake-header", "fake value")
+			Expect(resp).NotTo(HaveHTTPHeaderWithValue("other-header", "fake value"))
+			Expect(resp).NotTo(HaveHTTPHeaderWithValue("fake-header", "other value"))
+		})
+	})
+
+	When("ACTUAL is neither *http.Response nor *httptest.ResponseRecorder", func() {
+		It("errors", func() {
+			failures := InterceptGomegaFailures(func() {
+				Expect("foo").To(HaveHTTPHeaderWithValue("bar", "baz"))
+			})
+			Expect(failures).To(HaveLen(1))
+			Expect(failures[0]).To(Equal("HaveHTTPHeaderWithValue matcher expects *http.Response or *httptest.ResponseRecorder. Got:\n    <string>: foo"))
+		})
+	})
+
+	When("EXPECTED VALUE is a matcher", func() {
+		It("can match an HTTP header", func() {
+			resp := &http.Response{}
+			resp.Header = make(http.Header)
+			resp.Header.Add("fake-header", "fake value")
+			Expect(resp).To(HaveHTTPHeaderWithValue("fake-header", ContainSubstring("value")))
+		})
+
+		It("can mismatch an HTTP header", func() {
+			resp := &http.Response{}
+			resp.Header = make(http.Header)
+			resp.Header.Add("fake-header", "fake value")
+			Expect(resp).NotTo(HaveHTTPHeaderWithValue("fake-header", ContainSubstring("foo")))
+		})
+	})
+
+	When("EXPECTED VALUE is something else", func() {
+		It("errors", func() {
+			failures := InterceptGomegaFailures(func() {
+				resp := &http.Response{}
+				Expect(resp).To(HaveHTTPHeaderWithValue("bar", 42))
+			})
+			Expect(failures).To(HaveLen(1))
+			Expect(failures[0]).To(Equal("HaveHTTPHeaderWithValue matcher must be passed a string or a GomegaMatcher. Got:\n    <int>: 42"))
+		})
+	})
+
+	Describe("FailureMessage", func() {
+		When("matching a string", func() {
+			It("returns message", func() {
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{}
+					resp.Header = make(http.Header)
+					resp.Header.Add("fake-header", "fake value")
+					Expect(resp).To(HaveHTTPHeaderWithValue("fake-header", "other value"))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(Equal(`HTTP header "fake-header":
+    Expected
+        <string>: fake value
+    to equal
+        <string>: other value`), failures[0])
+			})
+		})
+
+		When("matching a matcher", func() {
+			It("returns message", func() {
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{}
+					resp.Header = make(http.Header)
+					resp.Header.Add("fake-header", "fake value")
+					Expect(resp).To(HaveHTTPHeaderWithValue("fake-header", ContainSubstring("other")))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(Equal(`HTTP header "fake-header":
+    Expected
+        <string>: fake value
+    to contain substring
+        <string>: other`), failures[0])
+			})
+		})
+	})
+
+	Describe("NegatedFailureMessage", func() {
+		When("matching a string", func() {
+			It("returns message", func() {
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{}
+					resp.Header = make(http.Header)
+					resp.Header.Add("fake-header", "fake value")
+					Expect(resp).NotTo(HaveHTTPHeaderWithValue("fake-header", "fake value"))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(Equal(`HTTP header "fake-header":
+    Expected
+        <string>: fake value
+    not to equal
+        <string>: fake value`), failures[0])
+			})
+		})
+
+		When("matching a matcher", func() {
+			It("returns message", func() {
+				failures := InterceptGomegaFailures(func() {
+					resp := &http.Response{}
+					resp.Header = make(http.Header)
+					resp.Header.Add("fake-header", "fake value")
+					Expect(resp).NotTo(HaveHTTPHeaderWithValue("fake-header", ContainSubstring("value")))
+				})
+				Expect(failures).To(HaveLen(1))
+				Expect(failures[0]).To(Equal(`HTTP header "fake-header":
+    Expected
+        <string>: fake value
+    not to contain substring
+        <string>: value`), failures[0])
+			})
+		})
+	})
+})