b2: factor version handling into lib/version

Standardizes the filename version tagging so that it can be used by any
backend.

lib/version/version_test.go

@@ -0,0 +1,73 @@
+package version_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/rclone/rclone/fstest"
+	"github.com/rclone/rclone/lib/version"
+	"github.com/stretchr/testify/assert"
+)
+
+var (
+	emptyT time.Time
+	t0     = fstest.Time("1970-01-01T01:01:01.123456789Z")
+	t0r    = fstest.Time("1970-01-01T01:01:01.123000000Z")
+	t1     = fstest.Time("2001-02-03T04:05:06.123000000Z")
+)
+
+func TestVersionAdd(t *testing.T) {
+	for _, test := range []struct {
+		t        time.Time
+		in       string
+		expected string
+	}{
+		{t0, "potato.txt", "potato-v1970-01-01-010101-123.txt"},
+		{t0, "potato-v2001-02-03-040506-123.txt", "potato-v2001-02-03-040506-123-v1970-01-01-010101-123.txt"},
+		{t0, "123.!!lipps", "123-v1970-01-01-010101-123.!!lipps"},
+		{t1, "potato", "potato-v2001-02-03-040506-123"},
+		{t1, "", "-v2001-02-03-040506-123"},
+	} {
+		actual := version.Add(test.in, test.t)
+		assert.Equal(t, test.expected, actual, test.in)
+	}
+}
+
+func TestVersionRemove(t *testing.T) {
+	for _, test := range []struct {
+		in             string
+		expectedT      time.Time
+		expectedRemote string
+	}{
+		{"potato.txt", emptyT, "potato.txt"},
+		{"potato-v1970-01-01-010101-123.txt", t0r, "potato.txt"},
+		{"potato-v2001-02-03-040506-123-v1970-01-01-010101-123.txt", t0r, "potato-v2001-02-03-040506-123.txt"},
+		{"potato-v2001-02-03-040506-123", t1, "potato"},
+		{"-v2001-02-03-040506-123", t1, ""},
+		{"potato-v2A01-02-03-040506-123", emptyT, "potato-v2A01-02-03-040506-123"},
+		{"potato-v2001-02-03-040506=123", emptyT, "potato-v2001-02-03-040506=123"},
+	} {
+		actualT, actualRemote := version.Remove(test.in)
+		assert.Equal(t, test.expectedT, actualT, test.in)
+		assert.Equal(t, test.expectedRemote, actualRemote, test.in)
+	}
+}
+
+func TestVersionMatch(t *testing.T) {
+	for _, test := range []struct {
+		in       string
+		expected bool
+	}{
+		{"potato.txt", false},
+		{"potato", false},
+		{"", false},
+		{"potato-v1970-01-01-010101-123.txt", true},
+		{"potato-v2001-02-03-040506-123-v1970-01-01-010101-123.txt", true},
+		{"potato-v2001-02-03-040506-123", true},
+		{"-v2001-02-03-040506-123", true},
+		{"-v9999-99-99-999999-999", true},
+	} {
+		actual := version.Match(test.in)
+		assert.Equal(t, test.expected, actual, test.in)
+	}
+}