restore: print JSON versions of errors in --json mode

Previously, they were printed as freeform text.

This also adds a ui.Terminal interface to make writing
tests easier and also adds a few tests.

internal/ui/backup/json.go

@@ -7,14 +7,13 @@ import (
 	"github.com/restic/restic/internal/archiver"
 	"github.com/restic/restic/internal/restic"
 	"github.com/restic/restic/internal/ui"
-	"github.com/restic/restic/internal/ui/termstatus"
 )
 
 // JSONProgress reports progress for the `backup` command in JSON.
 type JSONProgress struct {
 	*ui.Message
 
-	term *termstatus.Terminal
+	term ui.Terminal
 	v    uint
 }
 
@@ -22,7 +21,7 @@ type JSONProgress struct {
 var _ ProgressPrinter = &JSONProgress{}
 
 // NewJSONProgress returns a new backup progress reporter.
-func NewJSONProgress(term *termstatus.Terminal, verbosity uint) *JSONProgress {
+func NewJSONProgress(term ui.Terminal, verbosity uint) *JSONProgress {
 	return &JSONProgress{
 		Message: ui.NewMessage(term, verbosity),
 		term:    term,

internal/ui/backup/json_test.go

@@ -0,0 +1,27 @@
+package backup
+
+import (
+	"testing"
+
+	"github.com/restic/restic/internal/errors"
+	"github.com/restic/restic/internal/test"
+	"github.com/restic/restic/internal/ui"
+)
+
+func createJSONProgress() (*ui.MockTerminal, ProgressPrinter) {
+	term := &ui.MockTerminal{}
+	printer := NewJSONProgress(term, 3)
+	return term, printer
+}
+
+func TestJSONError(t *testing.T) {
+	term, printer := createJSONProgress()
+	test.Equals(t, printer.Error("/path", errors.New("error \"message\"")), nil)
+	test.Equals(t, []string{"{\"message_type\":\"error\",\"error\":\"error \\\"message\\\"\",\"during\":\"archival\",\"item\":\"/path\"}\n"}, term.Errors)
+}
+
+func TestJSONScannerError(t *testing.T) {
+	term, printer := createJSONProgress()
+	test.Equals(t, printer.ScannerError("/path", errors.New("error \"message\"")), nil)
+	test.Equals(t, []string{"{\"message_type\":\"error\",\"error\":\"error \\\"message\\\"\",\"during\":\"scan\",\"item\":\"/path\"}\n"}, term.Errors)
+}

internal/ui/backup/text.go

@@ -15,7 +15,7 @@ import (
 type TextProgress struct {
 	*ui.Message
 
-	term      *termstatus.Terminal
+	term      ui.Terminal
 	verbosity uint
 }
 
@@ -23,7 +23,7 @@ type TextProgress struct {
 var _ ProgressPrinter = &TextProgress{}
 
 // NewTextProgress returns a new backup progress reporter.
-func NewTextProgress(term *termstatus.Terminal, verbosity uint) *TextProgress {
+func NewTextProgress(term ui.Terminal, verbosity uint) *TextProgress {
 	return &TextProgress{
 		Message:   ui.NewMessage(term, verbosity),
 		term:      term,

internal/ui/backup/text_test.go

@@ -0,0 +1,27 @@
+package backup
+
+import (
+	"testing"
+
+	"github.com/restic/restic/internal/errors"
+	"github.com/restic/restic/internal/test"
+	"github.com/restic/restic/internal/ui"
+)
+
+func createTextProgress() (*ui.MockTerminal, ProgressPrinter) {
+	term := &ui.MockTerminal{}
+	printer := NewTextProgress(term, 3)
+	return term, printer
+}
+
+func TestError(t *testing.T) {
+	term, printer := createTextProgress()
+	test.Equals(t, printer.Error("/path", errors.New("error \"message\"")), nil)
+	test.Equals(t, []string{"error: error \"message\"\n"}, term.Errors)
+}
+
+func TestScannerError(t *testing.T) {
+	term, printer := createTextProgress()
+	test.Equals(t, printer.ScannerError("/path", errors.New("error \"message\"")), nil)
+	test.Equals(t, []string{"scan: error \"message\"\n"}, term.Errors)
+}