Test for every built-in dict methods

Set and test all these methods behavior which come with `dict` instance.
Some should be disabled since it's not go along with library concept
`clear()`
`get(<key>[, <default>])`
`items()`
`keys()`
`values()`
`pop(<key>[, <default>])` -> should be disabled
`popitem()` -> should be disabled
`update(<obj>)`