BClipboard(const char *name, bool transient = false)
case 1:	name is NULL =>
	(Note: R5 segfaults)
        create system clipboard
	Name() returns "system"
case 2: name points to valid string =>
	Name() returns a copy of name

status_t Clear(void)
case 1: BClipboard not locked =>
	return B_ERROR (R5 segfaults)
case 2: BClipboard is locked =>
	return B_OK
	Data() returns an empty message

status_t Commit(void)
case 1: BClipboard not locked =>
	return B_ERROR (R5 segfaults)
case 2: BClipboard is locked =>
	return B_OK
	data is uploaded to system

status_t Revert(void)
case 1: BClipboard not locked =>
	return B_ERROR (R5 segfaults)
case 2: BClipboard is locked =>
	return B_OK
	message returned by Data() is reset to value acquired on Lock()

BMessage *Data(void) const
case 1: BClipboard not locked =>
	return NULL (R5 segfaults)
case 2: BClipboard is locked =>
	returns a BMessage containing correct data

BMessenger DataSource(void) const
case 1: clipboard has never been written =>
	returns an invalid BMessenger
case 2: BClipboard has never been locked =>
	returns an invalid BMessenger
case 3: BClipboard has been locked at some point =>
  	returns BMessenger that wrote the data acquired in the last Lock()

uint32 LocalCount(void) const
case 1: BClipboard has not been read or written =>
	return 0
case 2: BClipboard "A" writes once, no other BClipboards write =>
	return 1
case 3: BClipboard "B" writes once, BClipboard "A" reads =>
	return 1 for both BClipboards
case 4: BClipboard "B" writes, BClipboard "A" reads, BClipboard "B" writes =>
	return 1 for BClipboard "A", return 2 for BClipboard "B"
case 5: BClipboard "A" writes, BClipboard "B" writes =>
	return 1 for BClipboard "A", return 2 for BClipboard "B"
case 6: BClipboard "A" writes to system clipboard "A", BClipboard "B" reads from system clipboard "B" =>
	return 1 for BClipboard "A", return 0 for BClipboard "B"

uint32 SystemCount(void) const
case 1: clipboard has never been written by any BClipboards =>
	return 0
case 2: BClipboard "A" writes, BClipboard "B" neither reads nor writes =>
	return 1 for both
case 3: BClipboard "A" writes to system clipboard "A", BClipboard "B" is attached to system clipboard "B" =>
	return 1 for BClipboard "A", return 0 for BClipboard "B"

bool Lock(void)
case 1: BClipboard is not locked by any threads =>
	return true
	data is downloaded from system
case 2: BClipboard is deleted while Lock() is blocked =>
	return false

bool IsLocked(void)
case 1: BClipboard is not locked =>
	return false
case 2: BClipboard is locked =>
	return true

void Lock(void)
case 1: BClipboard is locked =>
	unlocks clipboard (IsLocked returns false)

const char *Name(void) const
covered by constructor test cases

status_t StartWatching(BMessenger target)
case 1: =>
	return B_OK, target is notified when clipboard is written

status_t StopWatching(BMessenger target)
case 1: target is watching the BClipboard =>
	return B_OK
case 2: target is not watching the BClipboard =>
	return B_BAD_VALUE