dropbox: remove datastore - Fixes #55 #84

This means that dropbox no longer stores MD5SUMs and modified times.

Fixup the tests so that blank MD5SUMs are ignored, and that if
Precision is set to a fs.ModTimeNotSupported, ModTimes can be ignored too.

This opens the door for other FSs which don't support metadata easily.

fstest/fstest.go

@@ -30,10 +30,19 @@ type Item struct {
 	Size    int64
 }
 
+// Checks the times are equal within the precision, returns the delta and a flag
+func CheckTimeEqualWithPrecision(t0, t1 time.Time, precision time.Duration) (time.Duration, bool) {
+	dt := t0.Sub(t1)
+	if dt >= precision || dt <= -precision {
+		return dt, false
+	}
+	return dt, true
+}
+
 // check the mod time to the given precision
 func (i *Item) CheckModTime(t *testing.T, obj fs.Object, modTime time.Time, precision time.Duration) {
-	dt := modTime.Sub(i.ModTime)
-	if dt >= precision || dt <= -precision {
+	dt, ok := CheckTimeEqualWithPrecision(modTime, i.ModTime, precision)
+	if !ok {
 		t.Errorf("%s: Modification time difference too big |%s| > %s (%s vs %s) (precision %s)", obj.Remote(), dt, precision, modTime, i.ModTime, precision)
 	}
 }
@@ -47,7 +56,7 @@ func (i *Item) Check(t *testing.T, obj fs.Object, precision time.Duration) {
 	if err != nil {
 		t.Fatalf("Failed to read md5sum for %q: %v", obj.Remote(), err)
 	}
-	if i.Md5sum != Md5sum {
+	if !fs.Md5sumsEqual(i.Md5sum, Md5sum) {
 		t.Errorf("%s: Md5sum incorrect - expecting %q got %q", obj.Remote(), i.Md5sum, Md5sum)
 	}
 	if i.Size != obj.Size() {

fstest/fstests/fstests.go

@@ -258,6 +258,9 @@ func TestFsRmdirFull(t *testing.T) {
 func TestFsPrecision(t *testing.T) {
 	skipIfNotOk(t)
 	precision := remote.Precision()
+	if precision == fs.ModTimeNotSupported {
+		return
+	}
 	if precision > time.Second || precision < 0 {
 		t.Fatalf("Precision out of range %v", precision)
 	}
@@ -301,7 +304,7 @@ func TestObjectMd5sum(t *testing.T) {
 	if err != nil {
 		t.Errorf("Error in Md5sum: %v", err)
 	}
-	if Md5sum != file1.Md5sum {
+	if !fs.Md5sumsEqual(Md5sum, file1.Md5sum) {
 		t.Errorf("Md5sum is wrong %v != %v", Md5sum, file1.Md5sum)
 	}
 }
@@ -351,7 +354,7 @@ func TestObjectOpen(t *testing.T) {
 		t.Fatalf("in.Close() return error: %v", err)
 	}
 	Md5sum := hex.EncodeToString(hash.Sum(nil))
-	if Md5sum != file1.Md5sum {
+	if !fs.Md5sumsEqual(Md5sum, file1.Md5sum) {
 		t.Errorf("Md5sum is wrong %v != %v", Md5sum, file1.Md5sum)
 	}
 }