closes #743 - use filetype mode when choosing widget type

gooey/python_bindings/argparse_to_json.py

@@ -287,9 +287,12 @@ def categorize(actions, widget_dict, options):
         elif is_standard(action):
             yield action_to_json(action, _get_widget(action, 'TextField'), options)
         
-        elif is_file(action):
+        elif is_writemode_file(action):
             yield action_to_json(action, _get_widget(action, 'FileSaver'), options)
 
+        elif is_readmode_file(action):
+            yield action_to_json(action, _get_widget(action, 'FileChooser'), options)
+
         elif is_choice(action):
             yield action_to_json(action, _get_widget(action, 'Dropdown'), options)
 
@@ -355,6 +358,16 @@ def is_file(action):
     ''' action with FileType '''
     return isinstance(action.type, argparse.FileType)
 
+def is_readmode_file(action):
+    return is_file(action) and 'r' in action.type._mode
+
+def is_writemode_file(action):
+    # FileType uses the same modes as the builtin `open`
+    # as such, all modes that aren't explicitly `r` (which is
+    # also the default) are writable or read/writable, thus
+    # making a FileChooser a good choice.
+    return is_file(action) and 'r' not in action.type._mode
+
 def is_version(action):
     return isinstance(action, _VersionAction)
 

gooey/tests/test_argparse_to_json.py

@@ -1,12 +1,15 @@
 import argparse
 import sys
 import unittest
-from argparse import ArgumentParser
+from argparse import ArgumentParser, FileType
 
 from gooey import GooeyParser
 from gooey.python_bindings import argparse_to_json
 from gooey.util.functional import getin
 from gooey.tests import *
+from gui.components.options.options import FileChooser
+from gui.components.widgets import FileSaver
+
 
 class TestArgparse(unittest.TestCase):
 
@@ -259,3 +262,31 @@ class TestArgparse(unittest.TestCase):
             choices=["one", "two"],
             default="one",
         )
+
+
+    def test_filetype_chooses_good_widget(self):
+        """
+        #743 chose the picker type based on the FileType mode
+        when available.
+        """
+        cases = [
+            (FileType(), 'FileChooser'),
+            (FileType('r'), 'FileChooser'),
+            (FileType('rb'), 'FileChooser'),
+            (FileType('rt'), 'FileChooser'),
+            (FileType('w'), 'FileSaver'),
+            (FileType('wt'), 'FileSaver'),
+            (FileType('wb'), 'FileSaver'),
+            (FileType('a'), 'FileSaver'),
+            (FileType('x'), 'FileSaver'),
+            (FileType('+'), 'FileSaver'),
+        ]
+
+        for filetype, expected_widget in cases:
+            with self.subTest(f'expect {filetype} to produce {expected_widget})'):
+                parser = ArgumentParser()
+                parser.add_argument('foo', type=filetype)
+                action = [parser._actions[-1]]
+                result = next(argparse_to_json.categorize(action, {}, {}))
+                self.assertEqual(result['type'], expected_widget)
+