move Backend interface to backend package

internal/backend/file_test.go

@@ -0,0 +1,36 @@
+package backend
+
+import (
+	"testing"
+
+	rtest "github.com/restic/restic/internal/test"
+)
+
+func TestHandleString(t *testing.T) {
+	rtest.Equals(t, "<data/foobar>", Handle{Type: PackFile, Name: "foobar"}.String())
+	rtest.Equals(t, "<lock/1>", Handle{Type: LockFile, Name: "1"}.String())
+}
+
+func TestHandleValid(t *testing.T) {
+	var handleTests = []struct {
+		h     Handle
+		valid bool
+	}{
+		{Handle{Name: "foo"}, false},
+		{Handle{Type: 0}, false},
+		{Handle{Type: ConfigFile, Name: ""}, true},
+		{Handle{Type: PackFile, Name: ""}, false},
+		{Handle{Type: LockFile, Name: "010203040506"}, true},
+	}
+
+	for i, test := range handleTests {
+		err := test.h.Valid()
+		if err != nil && test.valid {
+			t.Errorf("test %v failed: error returned for valid handle: %v", i, err)
+		}
+
+		if !test.valid && err == nil {
+			t.Errorf("test %v failed: expected error for invalid handle not found", i)
+		}
+	}
+}