Simplify LabConfig

and increase the coverage

src/jupytext_config/jupytext_config.py

@@ -23,17 +23,12 @@ def main(self, args):
         """
         return 0 if all goes well
         """
-        print(
-            f"{self.__class__.__name__}: redefine main() to implement this subcommand"
-        )
-        return 1
+        raise NotImplementedError()  # pragma: no cover
 
 
 class ListDefaultViewer(SubCommand):
     def __init__(self):
-        super().__init__(
-            "list-default-viewer", "Display current settings in labconfig/"
-        )
+        super().__init__("list-default-viewer", "Display current settings in labconfig")
 
     def main(self, args):
         LabConfig(settings_file=args.settings_file).read().list_default_viewer()

src/jupytext_config/labconfig.py

@@ -5,11 +5,8 @@
 notebook will cause jupyterlab to open it in an editor, i.e. as a text file
 """
 
-import copy
 import json
 import logging
-
-# import pprint
 from pathlib import Path
 
 DEFAULT_SETTINGS_FILE = (
@@ -28,38 +25,36 @@ class LabConfig:
         "r",
     ]
 
-    def __init__(self, logger=None, settings_file=DEFAULT_SETTINGS_FILE):
+    def __init__(self, *, settings_file, logger=None):
+        self.settings_file = Path(settings_file)
         self.logger = logger or logging.getLogger(__name__)
         self.config = {}
-        # the state before any changes
-        self._prior_config = {}
-        self.settings_file = Path(settings_file)
 
     def read(self):
         """
         read the labconfig settings file
         """
-        try:
-            if self.settings_file.exists():
-                with self.settings_file.open() as fid:
-                    self.config = json.load(fid)
-        except OSError as exc:
-            self.logger.error(f"Could not read {self.settings_file}", exc)
-            return False
-        # store for further comparison
-        self._prior_config = copy.deepcopy(self.config)
+        if self.settings_file.exists():
+            with self.settings_file.open() as fid:
+                self.config = json.load(fid)
+        else:
+            self.logger.info(f"Could not read from {self.settings_file} (not found)")
+
         return self
 
+    def get_viewers(self):
+        return self.config.setdefault(
+            "@jupyterlab/docmanager-extension:plugin", {}
+        ).setdefault("defaultViewers", {})
+
     def list_default_viewer(self):
         """
         list the current labconfig settings
         """
         self.logger.debug(
             f"Current @jupyterlab/docmanager-extension:plugin in {self.settings_file}"
         )
-        docmanager = self.config.get("@jupyterlab/docmanager-extension:plugin", {})
-        viewers = docmanager.get("defaultViewers", {})
-        for key, value in viewers.items():
+        for key, value in self.get_viewers().items():
             print(f"{key}: {value}")
 
     def set_default_viewers(self, doctypes=None):
@@ -70,18 +65,7 @@ def set_default_viewers(self, doctypes=None):
         return self
 
     def set_default_viewer(self, doctype):
-        if "@jupyterlab/docmanager-extension:plugin" not in self.config:
-            self.config["@jupyterlab/docmanager-extension:plugin"] = {}
-        if (
-            "defaultViewers"
-            not in self.config["@jupyterlab/docmanager-extension:plugin"]
-        ):
-            self.config["@jupyterlab/docmanager-extension:plugin"][
-                "defaultViewers"
-            ] = {}
-        viewers = self.config["@jupyterlab/docmanager-extension:plugin"][
-            "defaultViewers"
-        ]
+        viewers = self.get_viewers()
         if doctype not in viewers:
             viewers[doctype] = "Jupytext Notebook"
 
@@ -93,30 +77,14 @@ def unset_default_viewers(self, doctypes=None):
         return self
 
     def unset_default_viewer(self, doctype):
-        viewers = self.config.get("@jupyterlab/docmanager-extension:plugin", {}).get(
-            "defaultViewers", {}
-        )
-        if doctype not in viewers:
-            return
-        del viewers[doctype]
+        viewers = self.get_viewers()
+        if doctype in viewers:
+            del viewers[doctype]
 
-    def write(self) -> bool:
+    def write(self):
         """
         write the labconfig settings file
         """
-        # compare - avoid changing the file if nothing changed
-        if self.config == self._prior_config:
-            self.logger.info(f"Nothing to do for {self.settings_file}")
-            return True
-
-        # save
-        try:
-            self.settings_file.parent.mkdir(parents=True, exist_ok=True)
-            with self.settings_file.open("w") as fid:
-                json.dump(self.config, fid, indent=2)
-            # useful in case of successive write's
-            self._prior_config = copy.deepcopy(self.config)
-            return True
-        except OSError as exc:
-            self.logger.error(f"Could not write {self.settings_file}", exc)
-            return False
+        self.settings_file.parent.mkdir(parents=True, exist_ok=True)
+        with self.settings_file.open("w") as fid:
+            json.dump(self.config, fid, indent=2)

tests/integration/jupytext_config/test_jupytext_config.py

@@ -16,3 +16,15 @@ def test_jupytext_config_cli(tmp_path):
     assert "markdown" in system(
         "jupytext-config", "--settings-file", settings_file, "list-default-viewer"
     )
+    system(
+        "jupytext-config",
+        "--settings-file",
+        str(settings_file),
+        "unset-default-viewer",
+        "markdown",
+    )
+    list_viewers = system(
+        "jupytext-config", "--settings-file", settings_file, "list-default-viewer"
+    )
+    assert "python" in list_viewers
+    assert "markdown" not in list_viewers

tests/unit/test_labconfig.py

@@ -6,7 +6,7 @@
 
 
 @pytest.fixture()
-def sample_lab_config():
+def sample_viewer_config():
     return {
         "@jupyterlab/docmanager-extension:plugin": {
             "defaultViewers": {
@@ -22,25 +22,34 @@ def sample_lab_config():
     }
 
 
+@pytest.fixture()
+def sample_empty_viewer_config():
+    return {"@jupyterlab/docmanager-extension:plugin": {"defaultViewers": {}}}
+
+
 @pytest.fixture()
 def settings_file(tmp_path):
     return tmp_path / "default_setting_overrides.json"
 
 
-def test_read_config(settings_file, sample_lab_config):
-    (settings_file).write_text(json.dumps(sample_lab_config))
+def test_read_config(settings_file, sample_viewer_config):
+    (settings_file).write_text(json.dumps(sample_viewer_config))
     labconfig = LabConfig(settings_file=settings_file).read()
-    assert labconfig.config == sample_lab_config
+    assert labconfig.config == sample_viewer_config
 
 
-def test_set_default_viewers(settings_file, sample_lab_config):
+def test_set_unset_default_viewers(
+    settings_file, sample_viewer_config, sample_empty_viewer_config
+):
     labconfig = LabConfig(settings_file=settings_file)
     labconfig.set_default_viewers()
-    assert labconfig.config == sample_lab_config
+    assert labconfig.config == sample_viewer_config
+    labconfig.unset_default_viewers()
+    assert labconfig.config == sample_empty_viewer_config
 
 
-def test_write_config(settings_file, sample_lab_config):
+def test_write_config(settings_file, sample_viewer_config):
     labconfig = LabConfig(settings_file=settings_file)
     labconfig.set_default_viewers()
     labconfig.write()
-    assert json.loads(settings_file.read_text()) == sample_lab_config
+    assert json.loads(settings_file.read_text()) == sample_viewer_config