settings: Add OutputFormat enum

This prepares for refactoring how we determine output format

fawltydeps/main.py

@@ -27,7 +27,7 @@
 from fawltydeps import extract_imports
 from fawltydeps.check import compare_imports_to_dependencies
 from fawltydeps.extract_declared_dependencies import extract_declared_dependencies
-from fawltydeps.settings import Action, Settings
+from fawltydeps.settings import Action, OutputFormat, Settings
 from fawltydeps.types import (
     ArgParseError,
     DeclaredDependency,
@@ -177,7 +177,7 @@ def main() -> int:
     except ArgParseError as exc:
         return parser.error(exc.msg)  # exit code 2
 
-    if settings.json_output:
+    if settings.output_format == OutputFormat.JSON:
         analysis.print_json(sys.stdout)
     else:
         analysis.print_human_readable(sys.stdout, details=settings.verbosity > 0)

fawltydeps/settings.py

@@ -67,6 +67,13 @@ class Action(OrderedEnum):
     REPORT_UNUSED = "check_unused"
 
 
+class OutputFormat(OrderedEnum):
+    """Output formats provided by the FawltyDeps application."""
+
+    HUMAN_READABLE = "human_readable"
+    JSON = "json"
+
+
 def parse_path_or_stdin(arg: str) -> PathOrSpecial:
     """Convert --code argument into Path or "<stdin>"."""
     if arg == "-":
@@ -91,7 +98,7 @@ class Settings(BaseSettings):  # type: ignore
     actions: Set[Action] = {Action.REPORT_UNDECLARED, Action.REPORT_UNUSED}
     code: PathOrSpecial = Path(".")
     deps: Path = Path(".")
-    json_output: bool = False
+    output_format: OutputFormat = OutputFormat.HUMAN_READABLE
     ignore_undeclared: Set[str] = set()
     ignore_unused: Set[str] = set()
     verbosity: int = 0
@@ -216,8 +223,9 @@ def populate_parser_options(cls, parser: argparse._ActionsContainer) -> None:
         )
         parser.add_argument(
             "--json",
-            dest="json_output",
-            action="store_true",
+            dest="output_format",
+            action="store_const",
+            const="json",
             help="Generate JSON output instead of a human-readable report",
         )
         parser.add_argument(

tests/test_cmdline.py

@@ -155,7 +155,7 @@ def test_list_imports_json__from_py_file__prints_imports_from_file(write_tmp_fil
             "actions": ["list_imports"],
             "code": f"{tmp_path}/myfile.py",
             "deps": ".",
-            "json_output": True,
+            "output_format": "json",
             "ignore_undeclared": [],
             "ignore_unused": [],
             "verbosity": 0,
@@ -295,7 +295,7 @@ def test_list_deps_json__dir__prints_deps_from_requirements_txt(
             "actions": ["list_deps"],
             "code": ".",
             "deps": f"{tmp_path}",
-            "json_output": True,
+            "output_format": "json",
             "ignore_undeclared": [],
             "ignore_unused": [],
             "verbosity": 0,
@@ -472,7 +472,7 @@ def test_check_json__simple_project__can_report_both_undeclared_and_unused(
             "actions": ["check_undeclared", "check_unused"],
             "code": f"{tmp_path}",
             "deps": f"{tmp_path}",
-            "json_output": True,
+            "output_format": "json",
             "ignore_undeclared": [],
             "ignore_unused": [],
             "verbosity": 0,

tests/test_settings.py

@@ -8,7 +8,7 @@
 from pydantic import ValidationError
 from pydantic.env_settings import SettingsError  # pylint: disable=no-name-in-module
 
-from fawltydeps.settings import Action, Settings
+from fawltydeps.settings import Action, OutputFormat, Settings
 
 if sys.version_info >= (3, 11):
     from tomllib import TOMLDecodeError  # pylint: disable=no-member
@@ -19,7 +19,7 @@
     actions={Action.REPORT_UNDECLARED, Action.REPORT_UNUSED},
     code=Path("."),
     deps=Path("."),
-    json_output=False,
+    output_format=OutputFormat.HUMAN_READABLE,
     ignore_undeclared=set(),
     ignore_unused=set(),
     verbosity=0,