test: validate that schemas are up to date in unit testing

Also:
 - fix the schemas output so it's stable under our pre-commit hooks
 - docs: help the dev do the right thing when schemas are out of date

everyvoice/cli.py

@@ -287,10 +287,13 @@ def update_schemas(
     for filename, schema in SCHEMAS_TO_OUTPUT.items():
         if (schema_dir_path / filename).exists():
             raise FileExistsError(
-                f"Sorry a schema already exists for version {filename}. Please bump the minor version number and generate the schema again."
+                f"Sorry a schema already exists for version {filename}.\n"
+                "If it's already been published to the schema store, please bump the EveryVoice minor version number and generate the schemas again.\n"
+                "If the current minor version is still in development, just delete the schema files and try again."
             )
         with open(schema_dir_path / filename, "w") as f:
             json.dump(schema.model_json_schema(), f, indent=2)
+            f.write("\n")
 
 
 CLICK_APP = typer.main.get_group(app)

everyvoice/tests/test_cli.py

@@ -198,6 +198,17 @@ def test_update_schema(self):
                     )
                 )
 
+            for filename in SCHEMAS_TO_OUTPUT:
+                with open(Path(tmpdir) / filename, encoding="utf8") as f:
+                    new_schema = f.read()
+                with open(EV_DIR / ".schema" / filename, encoding="utf8") as f:
+                    saved_schema = f.read()
+                self.assertEqual(
+                    saved_schema,
+                    new_schema,
+                    'Schemas are out of date, please run "everyvoice update-schemas".',
+                )
+
     def test_inspect_checkpoint_help(self):
         result = self.runner.invoke(app, ["inspect-checkpoint", "--help"])
         self.assertIn("inspect-checkpoint [OPTIONS] MODEL_PATH", result.stdout)