Minor adjustments from pr comments

docs/web3.pm.rst

@@ -5,6 +5,7 @@ Package Manager API
 The ``web3.pm`` object exposes methods to interact with Packages as defined by `ERC 1123 <https://github.com/ethereum/EIPs/issues/1123>`_.
 
 To learn more about the EthPM spec, visit the `documentation <http://ethpm.github.io/ethpm-spec/>`__.
+To learn more about the Py-EthPM library used in this module, visit the `documentation <https://py-ethpm.readthedocs.io/en/latest/>`__.
 
 
 Attaching

tests/core/pm-module/conftest.py

@@ -54,7 +54,7 @@
 logging.basicConfig(stream=sys.stdout, level=logging.INFO, format="%(message)s")
 
 
-def w3():
+def setup_w3():
     genesis_overrides = {"gas_limit": 5500000}
     custom_genesis_params = PyEVMBackend._generate_genesis_params(
         overrides=genesis_overrides
@@ -219,7 +219,10 @@ def release_packages(registry):
     return registry
 
 
-W3 = w3()
+# Module-level variables used here for efficiency
+# Tests are written against the sample packages released in `release_packages()` above, if more 
+# tests are needed, they should take into account the releases that exist on a "loaded registry".
+W3 = setup_w3()
 FRESH_VY_REGISTRY = vy_registry(W3)
 FRESH_SOL_REGISTRY = sol_registry(W3)
 LOADED_VY_REGISTRY = release_packages(vy_registry(W3))

tests/core/pm-module/test_ens_integration.py

@@ -1,14 +1,14 @@
 import pytest
 
 from eth_utils import (
+    to_bytes,
     to_canonical_address,
 )
 from ethpm import (
     ASSETS_DIR,
 )
 
 from ens import ENS
-from web3 import Web3
 from web3.exceptions import (
     InvalidAddress,
 )
@@ -20,13 +20,10 @@
 
 def bytes32(val):
     if isinstance(val, int):
-        result = Web3.toBytes(val)
+        result = to_bytes(val)
     else:
         raise TypeError('val %r could not be converted to bytes')
-    if len(result) < 32:
-        return result.rjust(32, b'\0')
-    else:
-        return result
+    return result.rjust(32, b'\0')
 
 
 pytest_plugins = ["pytest_ethereum.plugins"]
@@ -46,6 +43,8 @@ def ens_setup(solc_deployer):
     ens_key = accounts.pop()
 
     # create ENS contract
+    # values borrowed from:
+    # https://github.com/ethereum/web3.py/blob/master/tests/ens/conftest.py#L109
     eth_labelhash = w3.keccak(text='eth')
     eth_namehash = bytes32(0x93cdeb708b7545dc668eb9280176169d1c33cfd8ed6f04690a0bcc88a93fc4ae)
     resolver_namehash = bytes32(0xfdd5d5de6dd63db72bbc2d487944ba13bf775b50a80805fe6fcaba9b0fba88f5)