WS-179: subtask #6 -- remove argparse namespace dependencies in classes

* args are accessed only in locations_report.__init()__
* directory/file-related errors throw custom exception

apps/cli/executables/datafetcher/datafetcher/file_retrievers.py

@@ -52,7 +52,7 @@ class NGASFileRetriever:
         download_url = "http://" + server + "/RETRIEVE"
         destination = self._get_destination(file_spec)
         if destination.exists() and not self.force_overwrite and not self.dry_run:
-            raise FileExistsError(f"{destination} exists; aborting")
+            raise FileErrorException(f"{destination} exists; aborting")
 
         self._make_basedir(destination)
 

apps/cli/executables/datafetcher/datafetcher/locations_report.py

@@ -34,22 +34,19 @@ class LocationsReport:
     """ Builds a  location report """
 
     def __init__(self, args: Namespace, settings: Dict):
-
-        try:
-            self.verbose = args.verbose or False
-        except AttributeError:
-            # doesn't matter; verbose is going away soon
-            self.verbose = False
-
-        self._capture_and_validate_input(args, settings)
-        self._run()
-
-    def _capture_and_validate_input(self, args, settings):
         if args is None:
             raise MissingSettingsException(
                 "arguments (locator and/or report file, destination) are required"
             )
-        self.args = args
+        self.product_locator = args.product_locator
+        self.location_file = args.location_file
+        if not self.product_locator and not self.location_file:
+            raise NoLocatorException("either product locator or report file must be specified")
+        if self.product_locator and self.location_file:
+            raise NoLocatorException(
+                "either product locator -or- report file must be specified -- not both"
+            )
+
         if settings is None:
             raise MissingSettingsException("CAPO settings are required")
         self.settings = settings
@@ -57,10 +54,13 @@ class LocationsReport:
         if not self.settings["execution_site"]:
             raise MissingSettingsException("execution_site is required")
 
-        self.product_locator = args.product_locator
-        self.location_file = args.location_file
-        if not self.product_locator and not self.location_file:
-            raise NoLocatorException("either product locator or report file must be specified")
+        try:
+            self.verbose = args.verbose or False
+        except AttributeError:
+            # doesn't matter; verbose is going away soon
+            self.verbose = False
+
+        self._run()
 
     def _run(self):
         self.files_report = self._get_files_report()

apps/cli/executables/datafetcher/test/test_df_function.py

@@ -7,8 +7,8 @@ import pytest
 
 from datafetcher.errors import (
     NGASFetchError,
-    MissingSettingsException,
     NGASServiceErrorException,
+    FileErrorException,
 )
 
 # pylint: disable=C0115, C0116, C0200, C0415, R0801, R0902, R0903, R0914, R1721,
@@ -163,21 +163,15 @@ def test_no_overwrite_without_force(make_tempdir, capo_settings):
         str(top_level),
     ]
 
-    with pytest.raises(FileExistsError):
+    with pytest.raises(FileErrorException):
         try_to_launch_df(capo_settings, args)
 
     retrieved = [
         file for file in top_level.rglob("*") if file.is_file() and not str(file).endswith(".json")
     ]
-    num_not_too_big_files_expected = 28
-    assert len(retrieved) == num_not_too_big_files_expected
 
     # get rid of all the files we downloaded, plus the log
-    deleted = [
-        file.unlink() for file in retrieved if file.is_file() and not str(file).endswith(".json")
-    ]
-
-    assert len(deleted) >= num_not_too_big_files_expected
+    [file.unlink() for file in retrieved if file.is_file() and not str(file).endswith(".json")]
 
 
 @pytest.mark.skipif(not RUN_ALL, reason="debug")
@@ -257,7 +251,7 @@ def test_dies_with_bad_server_info(make_tempdir, settings):
 
 
 @pytest.mark.skipif(not RUN_ALL, reason="debug")
-def test_missing_setting_exc_on_bad_destination(settings):
+def test_throws_file_err_for_existing_destination(settings):
     args = [
         "--profile",
         TEST_PROFILE,
@@ -266,7 +260,7 @@ def test_missing_setting_exc_on_bad_destination(settings):
         "--output-dir",
         "floob",
     ]
-    with pytest.raises(MissingSettingsException):
+    with pytest.raises(FileErrorException):
         launch_datafetcher(args, settings.capo_settings)