update content type function with tests

pkg/routing/content_types.go

@@ -4,6 +4,7 @@ package routing
 import (
 	"errors"
 	"path/filepath"
+	"strings"
 )
 
 // getContentType returns the http header safe content-type attribute for the
@@ -13,24 +14,27 @@ import (
 // BUG(george-e-shaw-iv) Does not cover the bulk of encountered content types on the web
 func GetContentType(path string) (string, error) {
 	var contentType string
-	fileType := filepath.Ext(path)
 
-	if fileType == "" {
-		return contentType, errors.New("Invalid path, contained no period-separated content-type")
+	path = filepath.Base(path)
+	ext := filepath.Ext(path)
+	fn := strings.TrimSuffix(path, ext)
+
+	if ext == "" || fn == "" {
+		return "", errors.New("Invalid file path")
 	}
 
-	switch fileType {
-	case "html":
+	switch ext {
+	case ".html":
 		contentType = "text/html"
-	case "css":
+	case ".css":
 		contentType = "text/css"
-	case "js":
+	case ".js":
 		contentType = "text/javascript"
-	case "png":
+	case ".png":
 		contentType = "image/png"
-	case "jpg":
+	case ".jpg":
 		fallthrough
-	case "jpeg":
+	case ".jpeg":
 		contentType = "image/jpeg"
 	default:
 		contentType = "text/plain"

pkg/routing/content_types_test.go

@@ -0,0 +1,36 @@
+package routing
+
+import (
+	"testing"
+)
+
+func TestContentType(t *testing.T) {
+	cases := []struct {
+		input string
+		mime  string
+		ok    bool
+	}{
+		{"/path/to/index.html", "text/html", true},
+		{"somepath/file.css", "text/css", true},
+		{"test.js", "text/javascript", true},
+		{"asdf.png", "image/png", true},
+		{"asdfpng", "", false},
+		{"/something.jpg", "image/jpeg", true},
+		{"/something.jpeg", "image/jpeg", true},
+		{"this/should/fail/.png", "", false},
+	}
+
+	for _, tc := range cases {
+		mime, err := GetContentType(tc.input)
+		if err != nil && tc.ok == true {
+			t.Fatalf("\nGetContentType(%s): Got an error, expected OK.", tc.input)
+		}
+		if err == nil && tc.ok == false {
+			t.Fatalf("\nGetContentType(%s): Expected error, got: %s", tc.input, tc.mime)
+		}
+		if mime != tc.mime {
+			t.Fatalf("\nGetContentType(%s):\nWant: %s\nGot: %s", tc.input, tc.mime, mime)
+		}
+	}
+
+}