Adds tests for the current state of the project when using TOML

setup.py

@@ -83,6 +83,7 @@ def launch_http_server(directory):
 tests_require = [
     "black",
     "mock",
+    "toml",
     "PyYAML",
     "pytest",
     "pytest-cov",

tests/test_configargparse.py

@@ -9,8 +9,9 @@
 import types
 import unittest
 from unittest import mock
+import textwrap
 
-from io import StringIO
+from io import BytesIO, StringIO
 
 if sys.version_info >= (3, 10):
     OPTIONAL_ARGS_STRING = "options"
@@ -60,7 +61,6 @@ def captured_output():
 
 
 class TestCase(unittest.TestCase):
-
     def initParser(self, *args, **kwargs):
         p = configargparse.ArgParser(*args, **kwargs)
         self.parser = replace_error_method(p)
@@ -1749,6 +1749,177 @@ def testYAMLConfigFileParser_w_ArgumentParser_parsed_values(self):
         assert args.level == 35
 
 
+class TestTomlConfigParser(unittest.TestCase):
+    def write_toml_file(self, content, obj=StringIO):
+        f = obj()
+        dedent = lambda x: x
+        if isinstance(content, str):
+            dedent = textwrap.dedent
+        f.write(dedent(content))
+        f.seek(0)
+        return f
+
+    def test_section(self):
+        f = self.write_toml_file(
+            """
+            [section]
+            key1 = 'toml1'
+            key2 = 'toml2'
+            """
+        )
+        parser = configargparse.TomlConfigParser(["section"])
+        self.assertEqual(parser.parse(f), {"key1": "toml1", "key2": "toml2"})
+
+    def test_no_sections(self):
+        f = self.write_toml_file(
+            """
+            [section]
+            key1 = 'toml1'
+            key2 = 'toml2'
+            """
+        )
+        parser = configargparse.TomlConfigParser([])
+        self.assertEqual(parser.parse(f), {})
+
+    def test_empty_section(self):
+        f = self.write_toml_file("[section]")
+        parser = configargparse.TomlConfigParser(["section"])
+        self.assertEqual(parser.parse(f), {})
+
+    def test_empty_file(self):
+        f = self.write_toml_file("")
+        parser = configargparse.TomlConfigParser(["section"])
+        self.assertEqual(parser.parse(f), {})
+
+    @unittest.expectedFailure  # Ints should be strings
+    def test_advanced(self):
+        f = self.write_toml_file(
+            """
+            [tool.section]
+            key1 = "toml1"
+            key2 = [1, 2, 3]
+            """
+        )
+        parser = configargparse.TomlConfigParser(["tool.section"])
+        self.assertEqual(parser.parse(f), {"key1": "toml1", "key2": ["1", "2", "3"]})
+
+    def test_fails_binary_read(self):
+        f = self.write_toml_file(
+            b"""[tool.section]\nkey1 = "toml1"
+            """,
+            obj=BytesIO,
+        )
+        parser = configargparse.TomlConfigParser(["tool.section"])
+        with self.assertRaises(configargparse.ConfigFileParserException):
+            parser.parse(f)
+
+
+class TestCompositeConfigParser(unittest.TestCase):
+    def setUp(self):
+        self.tmpdir = tempfile.TemporaryDirectory()
+        self.old_cwd = os.getcwd()
+        os.chdir(self.tmpdir.name)
+        self.parser = configargparse.ArgParser(
+            description="test",
+            default_config_files=["config.yaml", "config.toml", "config.ini"],
+            config_file_parser_class=configargparse.CompositeConfigParser(
+                [
+                    configargparse.IniConfigParser(["section"], False),
+                    configargparse.TomlConfigParser(["section"]),
+                    configargparse.YAMLConfigFileParser,
+                ]
+            ),
+        )
+        self.parser.add_argument("--config", is_config_file=True)
+        self.parser.add_argument("--key1", type=str)
+        self.parser.add_argument("--key2", type=str)
+
+    def tearDown(self):
+        os.chdir(self.old_cwd)
+        self.tmpdir.cleanup()
+
+    def write_yaml_file(self, content="[section]\nkey1: yaml1\nkey2: yaml2"):
+        with open("config.yaml", "w") as f:
+            f.write(content)
+
+    def write_ini_file(
+        self, content="[section]\nkey1=ini1\nkey2=ini2\n; this is an ini comment"
+    ):
+        with open("config.ini", "w") as f:
+            f.write(content)
+
+    def write_toml_file(
+        self,
+        content="[section]\nkey1 = 'toml1'\nkey2 = 'toml2'\nspecial.key = { a = 1 }\n# this is a toml comment",
+    ):
+        with open("config.toml", "w") as f:
+            f.write(content)
+
+    def write_toml_file_extra(self):
+        self.write_toml_file()
+        with open("config.toml", "a") as f:
+            f.write("\nkey3 = 'toml3'\nkey4 = 'toml4'")
+
+    def test_plain(self):
+        self.assertEqual(
+            vars(self.parser.parse_args([])),
+            {"config": None, "key1": None, "key2": None},
+        )
+
+    @unittest.expectedFailure  # unknown fields should be ignored
+    def test_with_all_configs(self):
+        self.write_yaml_file()
+        self.write_ini_file()
+        self.write_toml_file()
+        self.assertEqual(
+            vars(self.parser.parse_args([])),
+            {"config": None, "key1": "ini1", "key2": "ini2"},
+        )
+
+    @unittest.expectedFailure  # unknown fields should be ignored
+    def test_with_all_configs_override(self):
+        self.write_yaml_file()
+        self.write_ini_file()
+        self.write_toml_file()
+        self.assertEqual(
+            vars(self.parser.parse_args(["--key1", "val1"])),
+            {"config": None, "key1": "val1", "key2": "ini2"},
+        )
+
+    def test_missing_primary_config(self):
+        self.write_yaml_file()
+        self.assertEqual(
+            vars(self.parser.parse_args([])),
+            {"config": None, "key1": "yaml1", "key2": "yaml2"},
+        )
+
+    @unittest.expectedFailure  # unknown fields should be ignored
+    def test_toml(self):
+        self.write_yaml_file()
+        self.write_toml_file()
+        self.assertEqual(
+            vars(self.parser.parse_args([])),
+            {"config": None, "key1": "toml1", "key2": "toml2"},
+        )
+
+    @unittest.expectedFailure  # unknown fields should be ignored
+    def test_override_primary_config(self):
+        self.write_yaml_file()
+        self.write_ini_file()
+        self.write_toml_file()
+        self.assertEqual(
+            vars(self.parser.parse_args(["--config", "config.yaml"])),
+            {"config": "config.yaml", "key1": "yaml1", "key2": "yaml2"},
+        )
+
+    def test_toml_extra(self):
+        self.write_yaml_file()
+        self.write_ini_file()
+        self.write_toml_file_extra()
+        with self.assertRaises(SystemExit):
+            self.parser.parse_args([])
+
+
 ################################################################################
 # since configargparse should work as a drop-in replacement for argparse
 # in all situations, run argparse unittests on configargparse by modifying