Relax command name format (#29)

acmd.go

@@ -39,7 +39,7 @@ type Command struct {
 	// Do will be invoked.
 	Do func(ctx context.Context, args []string) error
 
-	// subcommands of the command.
+	// Subcommands of the command.
 	Subcommands []Command
 
 	// IsHidden reports whether command should not be show in help. Default false.
@@ -241,7 +241,7 @@ func isStringValid(s string) bool {
 	}
 	for _, c := range s {
 		if !(('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z') ||
-			('0' <= c && c <= '9') || c == '-' || c == '_') {
+			('0' <= c && c <= '9') || c == '-' || c == '_' || c == ':') {
 			return false
 		}
 	}

acmd_test.go

@@ -204,6 +204,10 @@ func TestRunnerInit(t *testing.T) {
 		cfg        Config
 		wantErrStr string
 	}{
+		{
+			cmds:       []Command{{Name: "app:create", Do: nopFunc}},
+			wantErrStr: ``,
+		},
 		{
 			cmds:       []Command{{Name: "", Do: nopFunc}},
 			wantErrStr: `command "" must contains only letters, digits, - and _`,
@@ -276,7 +280,7 @@ func TestRunnerInit(t *testing.T) {
 	for _, tc := range testCases {
 		err := RunnerOf(tc.cmds, tc.cfg).Run()
 
-		if got := err.Error(); !strings.Contains(got, tc.wantErrStr) {
+		if got := err.Error(); tc.wantErrStr != "" && !strings.Contains(got, tc.wantErrStr) {
 			t.Fatalf("want %q got %q", tc.wantErrStr, got)
 		}
 	}