test: add unit tests for ContentType helpers and fix doc comments

content_type.go

@@ -24,6 +24,7 @@ const (
 	ContentTypeEventStream
 )
 
+// GetContentType returns the ContentType parsed from the given MIME media type string.
 func GetContentType(s string) ContentType {
 	s = strings.TrimSpace(strings.Split(s, ";")[0])
 	switch s {
@@ -64,6 +65,8 @@ func GetRequestContentType(r *http.Request) ContentType {
 	return GetContentType(r.Header.Get("Content-Type"))
 }
 
+// GetAcceptedContentType returns the ContentType requested by the client based on
+// the context or the request Accept header.
 func GetAcceptedContentType(r *http.Request) ContentType {
 	if contentType, ok := r.Context().Value(ContentTypeCtxKey).(ContentType); ok {
 		return contentType

content_type_test.go

@@ -0,0 +1,62 @@
+package render
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestGetContentType(t *testing.T) {
+	tests := []struct {
+		input string
+		want  ContentType
+	}{
+		{"text/plain", ContentTypePlainText},
+		{"text/html", ContentTypeHTML},
+		{"application/xhtml+xml", ContentTypeHTML},
+		{"application/json", ContentTypeJSON},
+		{"text/javascript", ContentTypeJSON},
+		{"text/xml", ContentTypeXML},
+		{"application/xml", ContentTypeXML},
+		{"application/x-www-form-urlencoded", ContentTypeForm},
+		{"text/event-stream", ContentTypeEventStream},
+		{"application/json; charset=utf-8", ContentTypeJSON},
+		{"unknown/type", ContentTypeUnknown},
+	}
+
+	for _, tt := range tests {
+		got := GetContentType(tt.input)
+		if got != tt.want {
+			t.Errorf("GetContentType(%q) = %v, want %v", tt.input, got, tt.want)
+		}
+	}
+}
+
+func TestGetAcceptedContentType(t *testing.T) {
+	req := httptest.NewRequest("GET", "/", nil)
+	req.Header.Set("Accept", "application/json, text/plain")
+
+	if got := GetAcceptedContentType(req); got != ContentTypeJSON {
+		t.Errorf("GetAcceptedContentType() = %v, want %v", got, ContentTypeJSON)
+	}
+
+	reqEmpty := httptest.NewRequest("GET", "/", nil)
+	if got := GetAcceptedContentType(reqEmpty); got != ContentTypePlainText {
+		t.Errorf("GetAcceptedContentType() for empty Accept = %v, want %v", got, ContentTypePlainText)
+	}
+}
+
+func TestSetContentType(t *testing.T) {
+	handler := SetContentType(ContentTypeJSON)(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if got := GetRequestContentType(r); got != ContentTypeJSON {
+			t.Errorf("GetRequestContentType inside handler = %v, want %v", got, ContentTypeJSON)
+		}
+		if got := GetAcceptedContentType(r); got != ContentTypeJSON {
+			t.Errorf("GetAcceptedContentType inside handler = %v, want %v", got, ContentTypeJSON)
+		}
+	}))
+
+	req := httptest.NewRequest("GET", "/", nil)
+	w := httptest.NewRecorder()
+	handler.ServeHTTP(w, req)
+}

render.go

@@ -24,7 +24,7 @@ func Bind(r *http.Request, v Binder) error {
 	return binder(r, v)
 }
 
-// Render renders a single payload and respond to the client request.
+// Render renders a single payload and responds to the client request.
 func Render(w http.ResponseWriter, r *http.Request, v Renderer) error {
 	if err := renderer(w, r, v); err != nil {
 		return err