Write web3.pm.get_local_package()

tests/conftest.py

@@ -11,8 +11,6 @@
     get_open_port,
 )
 
-pytest_plugins = ["pytest_ethereum.plugins"]
-
 
 @pytest.fixture(scope="module", params=[lambda x: to_bytes(hexstr=x), identity])
 def address_conversion_func(request):

tests/core/pm-module/test_pm_init.py

@@ -1,3 +1,4 @@
+import json
 import pytest
 
 from eth_utils import (
@@ -13,6 +14,10 @@
     get_manifest as get_ethpm_manifest,
 )
 
+from web3.exceptions import (
+    PMError,
+)
+
 
 def test_pm_init_with_minimal_manifest(w3):
     owned_manifest = get_ethpm_manifest('owned', '1.0.1.json')
@@ -89,3 +94,34 @@ def test_pm_init_with_manifest_uri(w3, monkeypatch):
     pkg = w3.pm.get_package_from_uri(dummy_standard_token_uri)
     assert isinstance(pkg, Package)
     assert pkg.name == "standard-token"
+
+
+@pytest.fixture
+def tmp_ethpmdir(tmp_path):
+    owned_manifest = get_ethpm_manifest("owned", "1.0.0.json")
+    ethpmdir = tmp_path / '_ethpm_packages'
+    ethpmdir.mkdir()
+    owned_dir = ethpmdir / 'owned'
+    owned_dir.mkdir()
+    manifest = owned_dir / 'manifest.json'
+    manifest.touch()
+    manifest.write_text(json.dumps(owned_manifest, sort_keys=True, separators=(",", ":")))
+    return ethpmdir
+
+
+def test_get_local_package(w3, tmp_ethpmdir):
+    pkg = w3.pm.get_local_package("owned", tmp_ethpmdir)
+    assert isinstance(pkg, Package)
+    assert pkg.name == "owned"
+
+
+def test_get_local_package_with_invalid_ethpmdir(w3, tmp_path):
+    invalid_ethpmdir = tmp_path / 'invalid'
+    invalid_ethpmdir.mkdir()
+    with pytest.raises(PMError, match="not a valid ethPM packages directory."):
+        w3.pm.get_local_package("owned", invalid_ethpmdir)
+
+
+def test_get_local_package_with_uninstalled_package(w3, tmp_ethpmdir):
+    with pytest.raises(PMError, match="Package: safe-math not found in "):
+        w3.pm.get_local_package("safe-math", tmp_ethpmdir)

web3/pm.py

@@ -3,6 +3,9 @@
     abstractmethod,
 )
 import json
+from pathlib import (
+    Path,
+)
 from typing import (
     Any,
     Dict,
@@ -421,6 +424,33 @@ def get_package_from_uri(self, manifest_uri: URI) -> Package:
         """
         return Package.from_uri(manifest_uri, self.web3)
 
+    def get_local_package(self, package_name: str, ethpm_dir: Path = None) -> Package:
+        """
+        Returns a `Package <https://github.com/ethpm/py-ethpm/blob/master/ethpm/package.py>`__
+        instance built with the Manifest found at the package name in your local ethpm_dir.
+
+        * Parameters:
+            * ``package_name``: Must be the name of a package installed locally.
+            * ``ethpm_dir``: Path pointing to the target ethpm directory (optional).
+        """
+        if not ethpm_dir:
+            ethpm_dir = Path.cwd() / '_ethpm_packages'
+
+        if not ethpm_dir.name == "_ethpm_packages" or not ethpm_dir.is_dir():
+            raise PMError(f"{ethpm_dir} is not a valid ethPM packages directory.")
+
+        local_packages = [pkg.name for pkg in ethpm_dir.iterdir() if pkg.is_dir()]
+        if package_name not in local_packages:
+            raise PMError(
+                f"Package: {package_name} not found in {ethpm_dir}. "
+                f"Available packages include: {local_packages}."
+            )
+
+        target_manifest = json.loads(
+            (ethpm_dir / package_name / "manifest.json").read_text()
+        )
+        return self.get_package_from_manifest(target_manifest)
+
     def set_registry(self, address: Address) -> None:
         """
         Sets the current registry used in ``web3.pm`` functions that read/write to an on-chain
@@ -488,13 +518,13 @@ def release_package(
         validate_raw_manifest_format(raw_manifest)
         manifest = json.loads(raw_manifest)
         validate_manifest_against_schema(manifest)
-        if package_name != manifest['package_name']:
+        if package_name != manifest["package_name"]:
             raise ManifestValidationError(
                 f"Provided package name: {package_name} does not match the package name "
                 f"found in the manifest: {manifest['package_name']}."
             )
 
-        if version != manifest['version']:
+        if version != manifest["version"]:
             raise ManifestValidationError(
                 f"Provided package version: {version} does not match the package version "
                 f"found in the manifest: {manifest['version']}."