error if no files

Author: rmorshea

src/idom/_console/update_html_usages.py

@@ -15,6 +15,7 @@
 import click
 
 from idom import html
+from idom._console.utils import error
 
 
 CAMEL_CASE_SUB_PATTERN = re.compile(r"(?<!^)(?=[A-Z])")
@@ -53,12 +54,19 @@ def update_html_usages(directories: list[str]) -> None:
     """
     if sys.version_info < (3, 9):  # pragma: no cover
         raise RuntimeError("This command requires Python>=3.9")
+
+    at_leat_one_file = False
     for d in directories:
         for file in Path(d).rglob("*.py"):
+            at_leat_one_file = True
             result = generate_rewrite(file=file, source=file.read_text())
             if result is not None:
                 file.write_text(result)
 
+    if not at_leat_one_file:
+        error("Found no Python files in the given directories.")
+        sys.exit(1)
+
 
 def generate_rewrite(file: Path, source: str) -> str | None:
     tree = ast.parse(source)

src/idom/_console/utils.py

@@ -0,0 +1,5 @@
+import click
+
+
+def error(text: str) -> None:
+    click.echo(f"{click.style('Error', fg='red')}: {text}")

tests/test__console/test_update_html_usages.py

@@ -27,6 +27,14 @@ def test_update_html_usages(tmp_path):
     assert tempfile.read_text() == "html.div(class_name=test)"
 
 
+def test_update_html_usages_no_files(tmp_path):
+    runner = CliRunner()
+
+    result = runner.invoke(update_html_usages, "directory-does-no-exist")
+    assert result.exit_code == 1
+    assert "Found no Python files" in result.stdout
+
+
 @pytest.mark.parametrize(
     "source, expected",
     [