Merge branch 'main' into id

common/testing/testing.v

@@ -8,30 +8,15 @@ import regex
 // so that they can be used as more specific errors,
 // in place of `return error(message)`
 struct DidNotFailError implements IError {
-	Error
-	msg string
-}
-
-pub fn (err DidNotFailError) msg() string {
-	return err.msg()
+	MessageError
 }
 
 struct DoesNotWorkError implements IError {
-	Error
-	msg string
-}
-
-pub fn (err DoesNotWorkError) msg() string {
-	return err.msg()
+	MessageError
 }
 
 struct ExitCodesDifferError implements IError {
-	Error
-	msg string
-}
-
-pub fn (err ExitCodesDifferError) msg() string {
-	return err.msg()
+	MessageError
 }
 
 // CommandPair remembers what original command we are trying to test against
@@ -61,6 +46,34 @@ pub fn (p CommandPair) same_results(options string) bool {
 	return same_results('${p.original} ${options}', '${p.deputy} ${options}')
 }
 
+// expected_failure - given some options, execute both the original
+// and the deputy commands with them, and ensure that they both fail
+// with the same exit_code
+pub fn (p CommandPair) expected_failure(options string) !os.Result {
+	ores := os.execute('${p.original} ${options}')
+	if ores.exit_code == 0 {
+		return DidNotFailError{
+			msg:  '${p.original} ${options}'
+			code: 1
+		}
+	}
+	dres := os.execute('${p.deputy} ${options}')
+	if dres.exit_code == 0 {
+		return DidNotFailError{
+			msg:  '${p.deputy} ${options}'
+			code: 2
+		}
+	}
+	if ores.exit_code != dres.exit_code {
+		return ExitCodesDifferError{
+			msg:  'original.exit_code: ${ores.exit_code} != deputy.exit_code: dres.exit_code'
+			code: 1
+		}
+	}
+	assert true
+	return dres
+}
+
 pub fn (p CommandPair) ensure_help_and_version_options_work() ! {
 	// For now, assume that the original has --version and --help
 	// and that they already work correctly.