Storage change tests

[chfast]

In preparation for EIP-1087.

For a single SSTORE of a given key, we have following cases:

• z: 0 -> 0 (zero),
• a: 0 -> X (added),
• d: X -> 0 (deleted),
• m: X -> Y (modified).
• u: X -> X (unchanged).

Make sure we have proper tests for all cases (probably yes).

Now let's create a set of test cases where we combine each possibility into sequence of two SSTORES:

• zz: 0 -> 0 -> 0
• za: 0 -> 0 -> X
• ad: 0 -> X -> 0
• am: 0 -> X -> Y
• au: 0 -> X -> X
• dz: X -> 0 -> 0
• da: X -> 0 -> X
• da2: X -> 0 -> Y
• md: X -> Y -> 0
• mm: X -> Y -> Z
• mm2: X -> Y -> X
• mu: X -> Y -> Y
• ud: X -> X -> 0
• um: X -> X -> Y
• uu: X -> X -> X

[winsvega]

Added to the list
https://docs.google.com/spreadsheets/d/1xat7UI8GtB4ZGVdlK5_XQSHJZaMThi4SrlcL8XMZb5Q/edit?pli=1#gid=878289780

[sorpaas]

Two additional test cases for reset and set again:

• ada: 0 -> X -> 0 -> X
• dad: X -> 0 -> X -> 0

[chfast]

Can this be closed now?

[winsvega]

No. The cases have not been added to the repo yet.
In fact tests not written yet.

[winsvega]

https://docs.google.com/spreadsheets/d/1xat7UI8GtB4ZGVdlK5_XQSHJZaMThi4SrlcL8XMZb5Q/edit?userstoinvite=hugo@ethereum.org&ts=5be5af56&actionButton=1#gid=878289780