[Test] Account package - test case set

[rianhughes]

Fix tests in the contracts folder

[rianhughes]

https://github.com/NethermindEth/starknet.go/tree/FixContractTest

[rianhughes]

Should we just absorb this into the accounts package, by making the contract-methods methods of the accounts pkg?

[stranger80]

Let's rename this one, and assume this includes creating a "sensible" test case set for account package. Recommended to include a sample of Cairo 2.x contract code and operate on that contract code sample to prove it works with Starknet.go.

This test suite shall include:

• Declare Cairo contract to the network
• Unit test for methods moved from "contracts" folder (eg WaitForTransaction())

Note: it may be sensible to have a single set of Cairo code "Assets"/artifacts, and refer to them from test cases, as well as library examples (in /examples folder).

[cicr99]

Adrressed by:

• New account #302
• Test declare txn #386
• Implement Wait For Transaction Receipt in accounts #389