Lazily import YAML libraries

Took 37 minutes

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = seddy
-version = 0.2.0a0.dev2
+version = 0.2.0a0.dev3
 url = https://github.com/EpicWink/seddy
 project_urls =
     Documentation = https://seddy.readthedocs.io/en/latest/

src/seddy/_util.py

@@ -9,14 +9,6 @@
 
 import boto3
 
-try:
-    import yaml
-except ImportError as e:  # pragma: no cover
-    try:
-        from ruamel import yaml
-    except ImportError:
-        yaml = e
-
 from . import decisions as seddy_decisions
 
 logger = lg.getLogger(__package__)
@@ -174,7 +166,12 @@ def load_workflows(workflows_file: pathlib.Path) -> t.Dict[str, t.Any]:
     if workflows_file.suffix == ".json":
         return json.loads(workflows_text)
     elif workflows_file.suffix in (".yml", ".yaml"):
-        if isinstance(yaml, Exception):
-            raise yaml
+        try:
+            import yaml
+        except ImportError as e:
+            try:
+                from ruamel import yaml
+            except ImportError as er:
+                raise e from er
         return yaml.safe_load(workflows_text)
     raise ValueError("Unknown extension: %s" % workflows_file.suffix)

tests/test_util.py

@@ -1,5 +1,6 @@
 """Test ``seddy._util``."""
 
+import sys
 import json
 from unittest import mock
 
@@ -75,17 +76,15 @@ def test_load_workflows_yaml(tmp_path, workflows_spec):
 def test_load_workflows_yaml_raises(tmp_path, workflows_spec):
     """Test workflows specs loading from YAML raises when unavailable."""
     # Setup environment
-    yaml_exc = ModuleNotFoundError("yaml")
-    yaml_patch = mock.patch.object(seddy_util, "yaml", yaml_exc)
+    yaml_patch = mock.patch.dict(sys.modules, {"yaml": None, "ruamel.yaml": None})
 
     # Build input
     workflows_file = tmp_path / "workflows.yml"
     workflows_file.write_text(yaml.safe_dump(workflows_spec))
 
     # Run function
-    with pytest.raises(ModuleNotFoundError) as e, yaml_patch:
+    with pytest.raises(ModuleNotFoundError), yaml_patch:
         seddy_util.load_workflows(workflows_file)
-    assert e.value == yaml_exc
 
 
 def test_load_workflows_with_incorrect_suffix(tmp_path, workflows_spec):