Add test for sending content to STDERR as well

src/carbon_txt/cli.py

@@ -24,6 +24,8 @@
     help="Validate carbon.txt files, either online, or locally.",
 )
 
+err_console = rich.console.Console(stderr=True)
+
 
 file_finder = finders.FileFinder()
 parser = parsers_toml.CarbonTxtParser()
@@ -103,8 +105,6 @@ def validate_file(
         _log_validated_carbon_txt_object(validation_results)
         return 1
 
-    return parsed_result
-
 
 @app.command()
 def schema():
@@ -113,8 +113,13 @@ def schema():
     """
     schema = CarbonTxtFile.model_json_schema()
 
-    rich.print(json.dumps(schema, indent=2))
-    return schema
+    err_console.print("JSON Schema for a carbon.txt file: \n")
+
+    if sys.stdout.isatty():
+        rich.print(json.dumps(schema, indent=2))
+    else:
+        print(json.dumps(schema, indent=2))
+    return 0
 
 
 def configure_django(

tests/test_cli.py

@@ -4,7 +4,7 @@
 
 from carbon_txt.cli import app
 
-runner = CliRunner()
+runner = CliRunner(mix_stderr=False)
 
 
 class TestCLI:
@@ -46,5 +46,6 @@ def test_schema(self):
         parsed_schema = json.loads(result.stdout)
 
         assert result.exit_code == 0
+        assert "JSON Schema for a carbon.txt file" in result.stderr
         assert "CarbonTxtFile" in parsed_schema.get("title")
         assert "$defs" in parsed_schema.keys()