Add SSH SFTP backend support

internal/adapters/ssh/options_test.go

@@ -0,0 +1,118 @@
+package ssh
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/distributor/internal/storage"
+	"github.com/pkg/sftp"
+)
+
+func TestOptionsNormalizeDefaultsUserPortAndHostKeyPolicy(t *testing.T) {
+	options, err := (Options{
+		Host: "example.com",
+		Root: "/reports",
+	}).normalized()
+	if err != nil {
+		t.Fatalf("normalized() error = %v", err)
+	}
+	if options.User == "" {
+		t.Fatal("normalized user is empty")
+	}
+	if options.Port != 22 {
+		t.Fatalf("port = %d, want 22", options.Port)
+	}
+	if options.HostKeyPolicy != HostKeyPolicyAcceptNew {
+		t.Fatalf("host key policy = %q, want accept-new", options.HostKeyPolicy)
+	}
+}
+
+func TestOptionsNormalizeRejectsInvalidFields(t *testing.T) {
+	tests := map[string]Options{
+		"host": {Root: "/reports"},
+		"port": {
+			Host: "example.com",
+			Port: 70000,
+			Root: "/reports",
+		},
+		"path": {
+			Host: "example.com",
+		},
+		"host key policy": {
+			Host:          "example.com",
+			Root:          "/reports",
+			HostKeyPolicy: "prompt",
+		},
+	}
+	for name, options := range tests {
+		t.Run(name, func(t *testing.T) {
+			if _, err := options.normalized(); err == nil {
+				t.Fatal("normalized() error = nil, want error")
+			}
+		})
+	}
+}
+
+func TestNativePathEnforcesLogicalPathRules(t *testing.T) {
+	backend := &Backend{root: "/srv/reports"}
+	tests := map[string]string{
+		"bundle/report.md": "/srv/reports/bundle/report.md",
+		"":                 "/srv/reports",
+	}
+	for logicalPath, want := range tests {
+		t.Run(logicalPath, func(t *testing.T) {
+			got, err := backend.nativePath(logicalPath, true)
+			if err != nil {
+				t.Fatalf("nativePath() error = %v", err)
+			}
+			if got != want {
+				t.Fatalf("nativePath() = %q, want %q", got, want)
+			}
+		})
+	}
+
+	for _, logicalPath := range []string{"/absolute", "../escape", "a/../b", `a\b`} {
+		t.Run("reject "+logicalPath, func(t *testing.T) {
+			_, err := backend.nativePath(logicalPath, true)
+			if err == nil || !storage.IsInvalidPath(err) {
+				t.Fatalf("nativePath() error = %v, want invalid path", err)
+			}
+		})
+	}
+}
+
+func TestNewRejectsMissingAuthBeforeDial(t *testing.T) {
+	t.Setenv("SSH_AUTH_SOCK", "")
+	_, err := New(context.Background(), Options{
+		Host:          "example.com",
+		User:          "reports",
+		Root:          "/reports",
+		HostKeyPolicy: HostKeyPolicyOff,
+	})
+	if err == nil || !strings.Contains(err.Error(), "no SSH auth methods configured") {
+		t.Fatalf("New() error = %v, want missing auth", err)
+	}
+}
+
+func TestTranslateErrorMapsSFTPStatusCodes(t *testing.T) {
+	backend := &Backend{}
+	tests := []struct {
+		name string
+		err  error
+		want storage.ErrorKind
+	}{
+		{name: "not found", err: sftp.ErrSSHFxNoSuchFile, want: storage.ErrNotFound},
+		{name: "permission", err: sftp.ErrSSHFxPermissionDenied, want: storage.ErrPermission},
+		{name: "unsupported", err: sftp.ErrSSHFxOpUnsupported, want: storage.ErrUnsupported},
+		{name: "temporary", err: sftp.ErrSSHFxConnectionLost, want: storage.ErrTemporary},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := backend.translateError(storage.OpStat, "report.md", tt.err)
+			if !storage.IsKind(err, tt.want) {
+				t.Fatalf("translateError() = %v, want kind %s", err, tt.want)
+			}
+		})
+	}
+}