Add addition guides

[iamonuwa]

What was wrong?

Added additional code examples to the docs

Related to Issue #
#1170

How was it fixed?

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[stefanmendoza]

Just an idea, but would it be better to just have the following in the example

from web3.auto import w3
import json

# Example call...

and have it use the default provider instead of assuming Infura and having to add an example key?

See: https://web3py.readthedocs.io/en/stable/providers.html#automatic-provider-detection

[iamonuwa]

@stefanmendoza understood. I'll make changes and update

[pipermerriam]

This is a great start. One thing I'd like to see is this to be doctested more thoroughly as well as removing some of the duplication in the process.

1: add a setup

You can use the .. testsetup directive to do some pre-setup that won't be rendered in the final docs to setup the w3 instance and/or parse the ABI.

99e14b3#diff-0c4e706274c9fa7b8006416f2043fb46R187

2: change to use doctest

All of the .. code-block:: python block can be converted to `.. doctest::`` directives:

99e14b3#diff-0c4e706274c9fa7b8006416f2043fb46R149

3: Convert to REPL style code blocks

If the code blocks are done as follows (as if the code was being typed into a python REPL, then the code will doctest a bit better as well as allowing you to actually test the print statements.

.. code-block:: python

    import sys
    print(sys.version)

This would become:

.. doctest

    >>> import sys
    >>> print(sys.version)
    '3.6.5 (default, Aug 27 2018, 12:56:57) \n[GCC 7.3.0]'

The result is that in our CI environment the code blocks will be run and confirmed against their outupt.

4: switch to use the eth-tester backed provider

Instead of using Infura which ends up querying live data, we should instead use the EthereumTesterProvider

from web3 import Web3
w3 = Web3(Web3.EthereumTesterProvider())

This will give you an in-memory web3 instance. You'll have to do the work in the .. testsetup directives to create and deploy the contracts you interact with.

[iamonuwa]

@pipermerriam thanks for the review. I'll update it

[pipermerriam]

We still need to get rid of the infura usage. See my comment on how to do this. Also, you can test these locally using tox -e doctest. Currently there are a number of failures you can see here: https://circleci.com/gh/ethereum/web3.py/41261?utm_campaign=vcs-integration-link&utm_medium=referral&utm_source=github-build-link

[iamonuwa]

@pipermerriam PTAL.

[pipermerriam]

@iamonuwa I'm sorry for the multiple iterations on this, these should be the last. Good work.

[pipermerriam]

@iamonuwa I ended up re-working a lot of this to remove any use of infura from the docs and to clean up your examples a bit. Just wanted to point it out to you so you can see it with a slightly cleaner structure.