Add echo headers handler

pkg/api/headers.go

@@ -0,0 +1,10 @@
+package api
+
+import (
+	"net/http"
+
+)
+
+func (s *Server) echoHeadersHandler(w http.ResponseWriter, r *http.Request) {
+	s.JSONResponse(w, r, r.Header)
+}

pkg/api/headers_test.go

@@ -0,0 +1,36 @@
+package api
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"regexp"
+	"testing"
+)
+
+func TestEchoHeadersHandler(t *testing.T) {
+	req, err := http.NewRequest("GET", "/api/headers", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("X-Test", "testing")
+	rr := httptest.NewRecorder()
+	srv := NewMockServer()
+	handler := http.HandlerFunc(srv.echoHeadersHandler)
+
+	handler.ServeHTTP(rr, req)
+
+	// Check the status code is what we expect.
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v",
+			status, http.StatusOK)
+	}
+
+	// Check the response body is what we expect.
+	expected := "testing"
+	r := regexp.MustCompile(fmt.Sprintf("(?m:%s)", expected))
+	if !r.MatchString(rr.Body.String()) {
+		t.Fatalf("handler returned unexpected body:\ngot \n%v \nwant \n%s",
+			rr.Body.String(), expected)
+	}
+}