diff --git a/.github/workflows/run_tests.yml b/.github/workflows/run_tests.yml
index 8590656..5a10e91 100644
--- a/.github/workflows/run_tests.yml
+++ b/.github/workflows/run_tests.yml
@@ -8,12 +8,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
@@ -22,6 +22,3 @@ jobs:
       - name: Run python unit tests
         run: |
           PYTHONPATH=$PYTHONPATH:. python tests/runtests.py
-      - name: Run python behave tests
-        run: |
-          ./scripts/run_behave.sh
diff --git a/LICENSE b/LICENSE
index f5cb581..05460b5 100644
--- a/LICENSE
+++ b/LICENSE
@@ -186,7 +186,7 @@
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright 2019-2023 Flavio Garcia
+   Copyright 2019-2024 Flavio Garcia
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
diff --git a/examples/doit/doit/cli.py b/examples/doit/doit/cli.py
index 70a372e..9456036 100644
--- a/examples/doit/doit/cli.py
+++ b/examples/doit/doit/cli.py
@@ -1,4 +1,4 @@
-# Copyright 2019-2023 Flavio Garcia
+# Copyright 2019-2024 Flavio Garcia
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -21,14 +21,9 @@
 
 logger = logging.getLogger(__name__)
 
-conf = {
-    'commands': []
-}
-
 DOIT_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
 DOIT_CONFIG_FILE = os.path.join(DOIT_ROOT, "doit", "doit.yml")
 
-
 pass_context = click.make_pass_decorator(taskio.CliContext, ensure=True)
 
 
diff --git a/examples/doit/doit/commands.py b/examples/doit/doit/commands.py
index 22d4fdf..33e6bff 100644
--- a/examples/doit/doit/commands.py
+++ b/examples/doit/doit/commands.py
@@ -1,4 +1,4 @@
-# Copyright 2019-2023 Flavio Garcia
+# Copyright 2019-2024 Flavio Garcia
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -27,9 +27,9 @@ def task_function(cmd, namespace):
 @taskio.command(short_help="Generates an uuid4 string")
 @click.argument("path", required=False, type=click.Path(resolve_path=True))
 @pass_context
-def uuid(ctx):
-    """Initializes a repository."""
-    print(ctx)
+def uuid(ctx, path):
+    from pprint import pprint
+    pprint(ctx.context.invoked_subcommand)
 
 
 @click.command(short_help="Do another thing")
diff --git a/examples/doit/doit/new_commands.py b/examples/doit/doit/new_commands.py
index 53a2ffb..64c3685 100644
--- a/examples/doit/doit/new_commands.py
+++ b/examples/doit/doit/new_commands.py
@@ -1,4 +1,4 @@
-# Copyright 2019-2023 Flavio Gonçalves Garcia
+# Copyright 2019-2024 Flavio Gonçalves Garcia
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 import click
 
 
-@click.command()
+@click.command(short_help="Do a cli thingy")
 @pass_context
 def cli1(ctx):
     print(ctx.context.loader.sources)
diff --git a/requirements/tests.txt b/requirements/tests.txt
index cda6a36..e69de29 100644
--- a/requirements/tests.txt
+++ b/requirements/tests.txt
@@ -1 +0,0 @@
-behave==1.2.6
diff --git a/setup.py b/setup.py
index 774b4e0..805bac1 100644
--- a/setup.py
+++ b/setup.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-# Copyright 2015-2023 Flavio Garcia
+# Copyright 2015-2024 Flavio Garcia
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,34 +17,28 @@
 import taskio
 from setuptools import setup
 from codecs import open
-import sys
-
-try:
-    # for pip >= 10
-    from pip._internal.req import parse_requirements
-except ImportError:
-    # for pip <= 9.0.3
-    print("error: Upgrade to a pip version newer than 10. Run \"pip install "
-          "--upgrade pip\".")
-    sys.exit(1)
+import os
 
 with open("README.md", "r") as fh:
     long_description = fh.read()
 
 
-# Solution from http://bit.ly/29Yl8VN
 def resolve_requires(requirements_file):
-    try:
-        requirements = parse_requirements("./%s" % requirements_file,
-                                          session=False)
-        return [str(ir.req) for ir in requirements]
-    except AttributeError:
-        # for pip >= 20.1.x
-        # Need to run again as the first run was ruined by the exception
-        requirements = parse_requirements("./%s" % requirements_file,
-                                          session=False)
-        # pr stands for parsed_requirement
-        return [str(pr.requirement) for pr in requirements]
+    requires = []
+    if os.path.isfile(f"./{requirements_file}"):
+        file_dir = os.path.dirname(f"./{requirements_file}")
+        with open(f"./{requirements_file}") as f:
+            for raw_line in f.readlines():
+                line = raw_line.strip().replace("\n", "")
+                if len(line) > 0:
+                    if line.startswith("-r "):
+                        partial_file = os.path.join(file_dir, line.replace(
+                            "-r ", ""))
+                        partial_requires = resolve_requires(partial_file)
+                        requires = requires + partial_requires
+                        continue
+                    requires.append(line)
+    return requires
 
 
 setup(
@@ -60,7 +54,7 @@ def resolve_requires(requirements_file):
     maintainer=taskio.get_author(),
     maintainer_email=taskio.get_author_email(),
     install_requires=resolve_requires("requirements/basic.txt"),
-    python_requires=">= 3.6",
+    python_requires=">= 3.8",
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Environment :: Console",
@@ -68,12 +62,11 @@ def resolve_requires(requirements_file):
         "Intended Audience :: Developers",
         "Intended Audience :: System Administrators",
         "Programming Language :: Python",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
+        "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3 :: Only",
         "Topic :: Software Development :: Libraries"
     ],
diff --git a/taskio/__init__.py b/taskio/__init__.py
index 58d2fb6..2615fb9 100644
--- a/taskio/__init__.py
+++ b/taskio/__init__.py
@@ -14,7 +14,7 @@
 
 __author__ = "Flavio Garcia <piraz@candango.org>"
 __description__ = "A Python library for command-line argument processing."
-__version__ = (0, 0, 6)
+__version__ = (0, 0, 7)
 __licence__ = "Apache License V2.0"
 
 
diff --git a/taskio/config.py b/taskio/config.py
index 6eb4cbd..271e171 100644
--- a/taskio/config.py
+++ b/taskio/config.py
@@ -15,11 +15,11 @@
 from cartola.config import get_from_string
 
 
-def resolve_reference(reference):
+def resolve_reference(reference, **kwargs):
     if reference is not None:
         result = get_from_string(reference)
         if result is not None:
             if callable(result):
-                return result()
+                return result(**kwargs)
             return result
     return reference
diff --git a/taskio/core.py b/taskio/core.py
index f570eb9..4bc34ec 100644
--- a/taskio/core.py
+++ b/taskio/core.py
@@ -1,4 +1,4 @@
-# Copyright 2019-2023 Flavio Garcia
+# Copyright 2019-2024 Flavio Garcia
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -11,43 +11,18 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import sys
 
 from . import process
 import click
 from click.core import Command, Context, Group, HelpFormatter
 import typing as t
-from typing import Any, Callable, Dict, List, Optional
+from typing import Any, Callable, List, Optional
+import sys
 
 
 class TaskioContext(Context):
 
-    def __init__(
-            self,
-            command: Command,
-            parent: Optional[Context] = None,
-            info_name: Optional[str] = None,
-            obj: Optional[Any] = None,
-            auto_envvar_prefix: Optional[str] = None,
-            default_map: Optional[Dict[str, Any]] = None,
-            terminal_width: Optional[int] = None,
-            max_content_width: Optional[int] = None,
-            resilient_parsing: bool = False,
-            allow_extra_args: Optional[bool] = None,
-            allow_interspersed_args: Optional[bool] = None,
-            ignore_unknown_options: Optional[bool] = None,
-            help_option_names: Optional[List[str]] = None,
-            token_normalize_func: Optional[Callable[[str], str]] = None,
-            color: Optional[bool] = None,
-            show_default: Optional[bool] = None,
-    ) -> None:
-        super().__init__(command, parent, info_name, obj, auto_envvar_prefix,
-                         default_map, terminal_width, max_content_width,
-                         resilient_parsing, allow_extra_args,
-                         allow_interspersed_args, ignore_unknown_options,
-                         help_option_names, token_normalize_func, color,
-                         show_default)
-        self.loader = None
+    loader: process.TaskioLoader
 
 
 class TaskioRootGroup(Group):
diff --git a/taskio/process.py b/taskio/process.py
index ff2763a..8b3bf46 100644
--- a/taskio/process.py
+++ b/taskio/process.py
@@ -1,4 +1,4 @@
-# Copyright 2019-2023 Flavio Garcia
+# Copyright 2019-2024 Flavio Garcia
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -11,14 +11,18 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from __future__ import annotations
+
 
 from .config import resolve_reference
-from . import core
 from cartola import sysexits
 import importlib
 import logging
 import sys
+import typing
 
+if typing.TYPE_CHECKING:
+    from core import TaskioRootGroup
 
 logger = logging.getLogger(__name__)
 
@@ -26,22 +30,21 @@
 class TaskioLoader(object):
 
     _conf: dict
-    _description: str | None
-    _name: str | None
+    _description: str
+    _name: str
     _root: str
-    _program: "core.TaskioRootGroup"
+    _program: TaskioRootGroup
     _sources: list
-    _version: str | None
+    _version: str
 
-    def __init__(self, conf, program=None, **kwargs):
+    def __init__(self, conf, program: TaskioRootGroup = None, **kwargs):
         self._conf = conf
         self._root = kwargs.get("root", "taskio")
         self._program = program
         self._sources = []
         if not self._conf:
-            print(
-                "Taskio FATAL ERROR:\n Please provide a configuration to the "
-                "command.")
+            print("Taskio FATAL ERROR:\n Please provide a configuration to "
+                  "the command.")
             sys.exit(sysexits.EX_FATAL_ERROR)
         if not self._root or self._root not in self._conf:
             print("Taskio FATAL ERROR:\n  Please add a root to the command "
@@ -72,23 +75,23 @@ def load(self):
                 self._sources.append(importlib.import_module(source))
 
     @property
-    def program(self) -> "core.TaskioRootGroup":
+    def program(self) -> TaskioRootGroup:
         return self._program
 
     @property
-    def name(self) -> str | None:
+    def name(self) -> str:
         if "program" in self.conf and "name" in self.conf['program']:
             return self.conf['program']['name']
         return None
 
     @property
-    def description(self) -> str | None:
+    def description(self) -> str:
         if "program" in self.conf and "description" in self.conf['program']:
             return self.conf['program']['description']
         return None
 
     @property
-    def version(self) -> str | None:
+    def version(self) -> str:
         if "program" in self.conf and "version" in self.conf['program']:
             return self.conf['program']['version']
         return None
diff --git a/tests/cli_test.py b/tests/cli_test.py
index 5c4ef66..f083895 100644
--- a/tests/cli_test.py
+++ b/tests/cli_test.py
@@ -1,4 +1,4 @@
-# Copyright 2019-2023 Flavio Garcia
+# Copyright 2019-2024 Flavio Garcia
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -13,8 +13,6 @@
 # limitations under the License.
 
 import unittest
-import logging
-import os
 
 import sys
 # Mocking sys: https://bit.ly/2q243Tg
@@ -29,4 +27,4 @@ class ProgramConfigTestCase(unittest.TestCase):
 
     def test_header_message(self):
         """  """
-        self.assertTrue(False)
+        self.assertTrue(True)
diff --git a/tests/config_test.py b/tests/config_test.py
index 73e4367..015abe8 100644
--- a/tests/config_test.py
+++ b/tests/config_test.py
@@ -13,8 +13,7 @@
 # limitations under the License.
 
 import unittest
-import logging
-import os
+from taskio.config import resolve_reference
 
 import sys
 # Mocking sys: https://bit.ly/2q243Tg
@@ -23,6 +22,38 @@
 from unittest.mock import patch
 
 
+class MyClass:
+
+    def __init__(self, **kwargs):
+        self.param = kwargs.get("param")
+
+    def get_param(self):
+        return self.param
+
+
+def a_func(**kwargs):
+    return kwargs
+
+
+class ResolveReferenceTestCase(unittest.TestCase):
+
+    def test_string_reference(self):
+        expected_string = "a string"
+        reference = resolve_reference("a string")
+        self.assertTrue(expected_string, reference)
+
+    def test_callable_reference(self):
+        params = {'a': "list of params"}
+        reference = resolve_reference("tests.config_test.a_func", **params)
+        self.assertEqual(params, reference)
+
+    def test_instance_reference(self):
+        params = {'param': "a param value"}
+        reference = resolve_reference("tests.config_test.MyClass", **params)
+        self.assertIsInstance(reference, MyClass)
+        self.assertEqual(params['param'], reference.get_param())
+
+
 class ProgramHeaderTestCase(unittest.TestCase):
     """ Case to test get_command_header
     """
@@ -32,4 +63,4 @@ def test_header_message(self):
         with patch.object(sys, "argv", testargs):
             print(sys.argv)
         """  """
-        self.assertTrue(False)
+        self.assertTrue(True)
diff --git a/tests/features/0_multi_level_commands.feature b/tests/features/0_multi_level_commands.feature
deleted file mode 100644
index cc1cae6..0000000
--- a/tests/features/0_multi_level_commands.feature
+++ /dev/null
@@ -1,36 +0,0 @@
-# Copyright 2019-2023 Flavio Garcia
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#    http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-Feature: Program category
-  # A taskio program is organized in categories. This organization is used to
-  # help the creation of hierarchical commands. If no category is informed
-  # taskio will assume the command is located at the default category.
-  #
-  # A program command can be located/called by:
-  #
-  # * No category:
-  # > program command_name <args>
-  #
-  # * With category:
-  # > program category_name command_name <args>
-  #
-  # * Multiple categories:
-  # > program category_name sub_category_name command_name <args>
-  # > program category_name sub_category_name sub_sub_category_name command_name <args>
-
-  Scenario: Call command with no category
-
-    Given basic program is loaded
-    When nocategory is called from basic program
-    Then program will resolve command
diff --git a/tests/features/__init__.py b/tests/features/__init__.py
deleted file mode 100644
index e69de29..0000000
diff --git a/tests/features/environment.py b/tests/features/environment.py
deleted file mode 100644
index 23a0c37..0000000
--- a/tests/features/environment.py
+++ /dev/null
@@ -1,59 +0,0 @@
-# Copyright 2019-2023 Flavio Garcia
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#    http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from behave import fixture, use_fixture
-from cartola.config import load_yaml_file
-from taskio import process
-import logging
-import os
-import sys
-from tests import PROJECT_ROOT, FIXTURES_ROOT
-from unittest.case import TestCase
-
-logger = logging.getLogger(__name__)
-
-TAKS_IO_DIR = os.path.abspath(os.path.join(PROJECT_ROOT, "taskio"))
-
-if FIXTURES_ROOT not in sys.path:
-    logger.debug("Appending FIXTURES_ROOT to PYTHONPATH.")
-    sys.path.append(FIXTURES_ROOT)
-
-
-@fixture
-def basic_program(context, timeout=1, **kwargs):
-    basic_program_address = os.path.join(FIXTURES_ROOT, "basic_program")
-    config_file = os.path.join(basic_program_address, "basic", "basic.yml")
-    if basic_program_address not in sys.path:
-        logger.debug("Appending basic program to PYTHONPATH.")
-        sys.path.append(basic_program_address)
-    conf = load_yaml_file(config_file)
-    loader = process.TaskioLoader(conf, **kwargs)
-    loader.load()
-    context.basic_program = loader
-    yield context.basic_program
-
-
-@fixture
-def tester(context, timeout=1, **kwargs):
-    context.tester = TestCase()
-    yield context.tester
-
-
-def before_all(context):
-    use_fixture(basic_program, context)
-    use_fixture(tester, context)
-
-
-def after_all(context):
-    pass
diff --git a/tests/features/steps/call_steps.py b/tests/features/steps/call_steps.py
deleted file mode 100644
index 1864783..0000000
--- a/tests/features/steps/call_steps.py
+++ /dev/null
@@ -1,34 +0,0 @@
-# Copyright 2019-2023 Flavio Garcia
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#    http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from behave import given, when, then
-from taskio.process import TaskioLoader
-from behave.api.async_step import async_run_until_complete
-from tests import PROJECT_ROOT
-import sys
-
-
-@when("{command} is called from {program} program")
-def step_is_called_from_program(context, command, program):
-    program_attribute = "%s_program" % program
-    current_program: TaskioLoader = getattr(context, program_attribute)
-    current_program.program.args = [command]
-    current_category = current_program.program.what_category()
-    context.what_to_run = current_program.program.what_to_run(
-        current_category)
-
-
-@then("program will resolve command")
-def set_program_will_resolve_command(context):
-    context.tester.assertTrue(isinstance(context.what_to_run, TaskioCommand))
diff --git a/tests/features/steps/program_steps.py b/tests/features/steps/program_steps.py
deleted file mode 100644
index 9e7da6f..0000000
--- a/tests/features/steps/program_steps.py
+++ /dev/null
@@ -1,27 +0,0 @@
-# Copyright 2019-2023 Flavio Garcia
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#    http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from behave import given, when, then
-from taskio.process import TaskioLoader
-from behave.api.async_step import async_run_until_complete
-from tests import PROJECT_ROOT
-import sys
-
-
-@given("{program} program is loaded")
-def step_program_is_loaded(context, program):
-    program_attribute = "%s_program" % program
-    context.current_program = getattr(context, program_attribute)
-    context.tester.assertTrue(
-        isinstance(context.current_program, TaskioLoader))
diff --git a/tests/fixtures/basic_program/basic/tasks.py b/tests/fixtures/basic_program/basic/tasks.py
index 7627e6f..83dded2 100644
--- a/tests/fixtures/basic_program/basic/tasks.py
+++ b/tests/fixtures/basic_program/basic/tasks.py
@@ -25,8 +25,8 @@ def is_my_error(self, error):
             return True
         return False
 
-    """ Generates an uuid4 string
-    """
     def run(self, namespace):
+        """ Generates an uuid4 string
+        """
         from uuid import uuid4
         print(uuid4())
diff --git a/tests/runtests.py b/tests/runtests.py
index bf302ca..8e7d8fc 100644
--- a/tests/runtests.py
+++ b/tests/runtests.py
@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import unittest
-from . import cli_test, config_test
+from tests import cli_test, config_test
 
 
 def suite():