Fix tests and downloads from GitHub (#47)

* Fix broken tests.

`TestBase16Render` needed the third argument - the app name.

Update `TestBase16ColorschemeList_GetBase16Colorscheme` to not rely on
network downloads. Instead, imbed the content of the file from github to
test the parsing.

* Treat non-200 HTTP codes as errors.

GitHub appears to now return a 404 when no GithubToken is specified.
Instead of failing to retrieve and having empty templates or repo lists,
return an error message to the user by propagating the HTTP error code.

* Permit ".yml" YAML files in scheme repositories.

Some schemes, like "vice", use the three-letter file extension.

colorscheme_test.go

@@ -102,7 +102,25 @@ func TestBase16ColorschemeList_GetBase16Colorscheme(t *testing.T) {
 }
 
 func TestNewBase16Colorscheme(t *testing.T) {
-	data1, _ := DownloadFileToString("https://raw.githubusercontent.com/atelierbram/base16-atelier-schemes/master/atelier-forest.yaml")
+	data1 := `scheme: "Atelier Forest"
+author: "Bram de Haan (http://atelierbramdehaan.nl)"
+base00: "1b1918"
+base01: "2c2421"
+base02: "68615e"
+base03: "766e6b"
+base04: "9c9491"
+base05: "a8a19f"
+base06: "e6e2e0"
+base07: "f1efee"
+base08: "f22c40"
+base09: "df5320"
+base0A: "c38418"
+base0B: "7b9726"
+base0C: "3d97b8"
+base0D: "407ee7"
+base0E: "6666ea"
+base0F: "c33ff3"`
+
 	want1 := Base16Colorscheme{
 		Name:       "Atelier Forest",
 		Author:     "Bram de Haan (http://atelierbramdehaan.nl)",

helpers.go

@@ -38,6 +38,8 @@ func DownloadFileToString(url string) (string, error) {
 			return "", err
 		}
 		return string(bodyBytes), nil
+	} else if err == nil {
+		err = fmt.Errorf("HTTP code %v", resp.StatusCode)
 	}
 	return "", err
 }
@@ -79,7 +81,7 @@ func findYAMLinRepo(repoURL string) []GitHubFile {
 	// Create a list of .yaml files
 	var colorSchemes []GitHubFile
 	for _, v := range keys {
-		re := regexp.MustCompile(".*yaml")
+		re := regexp.MustCompile(".*ya?ml")
 		if re.MatchString(v.Name) {
 			colorSchemes = append(colorSchemes, v)
 		}

main_test.go

@@ -21,6 +21,7 @@ func TestBase16Render(t *testing.T) {
 	type args struct {
 		templ  Base16Template
 		scheme Base16Colorscheme
+		app string
 	}
 	tests := []struct {
 		name string
@@ -30,7 +31,7 @@ func TestBase16Render(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			Base16Render(tt.args.templ, tt.args.scheme)
+			Base16Render(tt.args.templ, tt.args.scheme, tt.args.app)
 		})
 	}
 }