def test_push():
operation_stack = OperationStack(MagicMock())
operation_stack.changed.emit = MagicMock()
test_operation = GroupedOperation()
test_operation_2 = GroupedOperation()
operation_stack.push(test_operation)
operation_stack.push(test_operation_2)
# Since we added two operations that can be merged, we should end up with one operation!
assert len(operation_stack.getOperations()) == 1
test_operation_3 = GroupedOperation()
# Fake call to notify the operation stack that the tool has stopped doing something
operation_stack._onToolOperationStopped(None)
# Pretend like another operation was added but with a lot of time in between.
test_operation_3._timestamp = time.time() + 2000000
operation_stack.push(test_operation_3)
assert len(operation_stack.getOperations()) == 2
operation_stack.undo()
# The count should be at 4, since we added 3 operations and then undid the last one.
assert operation_stack.changed.emit.call_count == 4
operation_stack.undo()
assert operation_stack.changed.emit.call_count == 5
# There is nothing to undo!
assert not operation_stack.canUndo()
operation_stack.undo()
assert operation_stack.changed.emit.call_count == 5
operation_stack.redo()
assert operation_stack.changed.emit.call_count == 6
operation_stack.redo()
assert operation_stack.changed.emit.call_count == 7
assert not operation_stack.canRedo()
