Add a function with the policy for deciding if we are in local vs. CDN mode.

Author: pauleveritt

src/psc/resources.py

@@ -4,23 +4,22 @@
 """
 from dataclasses import dataclass
 from dataclasses import field
-from pathlib import PurePath
+from pathlib import PurePath, Path
 from typing import cast
 
 import frontmatter
 from bs4 import BeautifulSoup
 from bs4 import Tag
 from markdown_it import MarkdownIt
 
-from psc.here import HERE
-
+from psc.here import HERE, PYODIDE
 
 EXCLUSIONS = ("pyscript.css", "pyscript.js", "favicon.png")
 
 
 def tag_filter(
-    tag: Tag,
-    exclusions: tuple[str, ...] = EXCLUSIONS,
+        tag: Tag,
+        exclusions: tuple[str, ...] = EXCLUSIONS,
 ) -> bool:
     """Filter nodes from example that should not get included."""
     attr = "href" if tag.name == "link" else "src"
@@ -46,6 +45,12 @@ def get_head_nodes(s: BeautifulSoup) -> str:
     return ""
 
 
+def is_local(test_path: Path | None = PYODIDE) -> bool:
+    """Use a policy to decide local vs. CDN mode."""
+
+    return test_path.exists()
+
+
 def get_body_content(s: BeautifulSoup) -> str:
     """Get the body node but raise an exception if not present."""
     body_element = s.select_one("body")

tests/test_resources.py

@@ -1,10 +1,10 @@
 """Construct the various kinds of resources: example, page, contributor."""
-from pathlib import PurePath
+from pathlib import PurePath, Path
 
 import pytest
 from bs4 import BeautifulSoup
 
-from psc.resources import Example
+from psc.resources import Example, is_local
 from psc.resources import Page
 from psc.resources import get_body_content
 from psc.resources import get_head_nodes
@@ -72,8 +72,8 @@ def test_example() -> None:
     this_example = Example(path=PurePath("hello_world"))
     assert this_example.title == "Hello World"
     assert (
-        this_example.subtitle
-        == "The classic hello world, but in Python -- in a browser!"
+            this_example.subtitle
+            == "The classic hello world, but in Python -- in a browser!"
     )
     assert "hello_world.css" in this_example.extra_head
     assert "<h1>Hello ...</h1>" in this_example.body
@@ -117,12 +117,25 @@ def test_get_resources() -> None:
     hello_world = resources.examples[hello_world_path]
     assert hello_world.title == "Hello World"
     assert (
-        hello_world.subtitle
-        == "The classic hello world, but in Python -- in a browser!"
+            hello_world.subtitle
+            == "The classic hello world, but in Python -- in a browser!"
     )
 
     # Page
     about_path = PurePath("about")
     about = resources.pages[about_path]
     assert about.title == "About the PyScript Collective"
     assert "<h1>Helping" in about.body
+
+
+def test_is_local_no_path() -> None:
+    """Test the local case where a directory exists."""
+    actual = is_local()
+    assert actual
+
+
+def test_is_local_broken_path() -> None:
+    """Test the local case where a directory will not exist."""
+    test_path = Path("/xxxxxx")
+    actual = is_local(test_path)
+    assert not actual