diff --git a/kloudbuster/kloudbuster.py b/kloudbuster/kloudbuster.py
index db68e69..e9bf0f5 100755
--- a/kloudbuster/kloudbuster.py
+++ b/kloudbuster/kloudbuster.py
@@ -902,8 +902,7 @@ def generate_charts(json_results, html_file_name, is_config):
                     is_config)
     return 0
 
-
-def main():
+def process_cli_args(args):
     cli_opts = [
         cfg.StrOpt("config",
                    short="c",
@@ -987,7 +986,10 @@ def main():
                    metavar="<source json file>"),
     ]
     CONF.register_cli_opts(cli_opts)
-    CONF(sys.argv[1:], project="kloudbuster", version=__version__)
+    CONF(args, project="kloudbuster", version=__version__)
+
+def main():
+    process_cli_args(sys.argv[1:])
     logging.setup("kloudbuster")
 
     if CONF.rc and not CONF.tested_rc:
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..6e37de9
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,93 @@
+"""
+This module is used to define shared pytest fixtures.
+Because this module is placed under tests, all fixtures defined here can be used
+by all test cases below tests
+"""
+import os
+import shutil
+
+import pytest
+
+def stage_file(dirname, filename, content=None):
+    # we cannot use a os.path.join because we want to support
+    # multi-parts in the filename
+    if dirname.endswith('/') and filename.startswith('/'):
+        pathname = dirname + filename[1:]
+    elif filename.startswith('/') or dirname.endswith('/'):
+        pathname = dirname + filename
+    else:
+        pathname = dirname + '/' + filename
+    print('Staging file: ', pathname)
+    os.makedirs(os.path.dirname(pathname), exist_ok=True)
+    if content is None:
+        content = pathname
+    with open(pathname, 'w') as ff:
+        ff.write(content)
+
+
+@pytest.fixture
+def stage_fs():
+    """
+    This fixture can be used to stage a complete file system below a given root.
+
+    This is a fixture factory and each test function can call stage_fs with the root of the
+    file system to stage and with a configuration.
+    The entire root_fs will be deleted when the fixture terminates unless skip_clean=True
+
+    Example of files_config:
+    {
+        'file1.yaml': 'any content',
+        'folder1': {
+            'file_with_arbitrary_content.yaml': None,
+            'empty_file.txt': '',
+            'nested_empty_folder: {}
+        }
+        'folder1/file2.txt': None
+    }
+    if '/tmp/pico' is passed as fs_root, this fixture will stage the following files:
+
+    /tmp/pico/file1.yaml (containing 'any content')
+    /tmp/pico/folder1/file_with_arbitrary_content.yaml (containing arbitary text)
+    /tmp/pico/folder1/empty_file.txt (empty)
+    /tmp/pico/folder1/nested_empty_folder/ (empty directory)
+    /tmp/pico/folder1/file2.txt (any content)
+
+
+    To use this fixture, simply add "stage_fs" as argument to your test function, then
+    call stage_fs() with arguments described in below _stage_fs function.
+    Also see the unit test code (test_fixtures.py)
+    """
+    saved_fs_root = []
+    def _stage_fs(fs_root, files_config, skip_clean=False):
+        """
+        fs_root: pathname of the root under which all all the files defined in files_config must be staged
+        files_config: a dict of file content reflecting the desired staged file system
+        skip_clean: set to True if you do not want the staged directory to be cleaned on exit (for troubleshooting only)
+        """
+        if not saved_fs_root:
+            if skip_clean:
+                # for troubleshooting, it is possible to preserve
+                # the stage_fs directory after the test finishes
+                saved_fs_root.append(None)
+            else:
+                saved_fs_root.append(fs_root)
+            # remove the stage_fs root directory at start
+            # so we're sure we start with a clean directory
+            shutil.rmtree(fs_root, ignore_errors=True)
+            os.makedirs(fs_root, exist_ok=True)
+
+        for file, content in files_config.items():
+            if isinstance(content, dict):
+                # remove any "/" at start
+                if file[0] == '/':
+                    file = file[1:]
+                new_fs_root = os.path.join(fs_root, file)
+                os.makedirs(new_fs_root, exist_ok=True)
+                _stage_fs(new_fs_root, content)
+            else:
+                stage_file(fs_root, file, content)
+    yield _stage_fs
+    if saved_fs_root:
+        if saved_fs_root[0]:
+            # remove the stage_fs directory when the fixture terminates
+            shutil.rmtree(saved_fs_root[0], ignore_errors=True)
diff --git a/tests/test_kloudbuster.py b/tests/test_kloudbuster.py
index a002cc6..714b1b6 100644
--- a/tests/test_kloudbuster.py
+++ b/tests/test_kloudbuster.py
@@ -19,7 +19,43 @@ test_kloudbuster
 Tests for `kloudbuster` module.
 """
 from kloudbuster.kb_config import KBConfig
+from kloudbuster.kloudbuster import process_cli_args
 
-def test_config():
-    cfg = KBConfig()
-    cfg.update_configs()
+def test_kbconfig_default():
+    # verify that we load the defaulgt config properly
+    kbcfg = KBConfig()
+    kbcfg.update_configs()
+    cfg = kbcfg.config_scale
+    assert cfg.openrc_file is None
+    assert cfg.vm_creation_concurrency == 5
+    assert cfg.client.flavor.vcpus == 1
+
+config_yaml = """
+client:
+    flavor:
+        vcpus: 100
+        ram: 2048
+        disk: 0
+        extra_specs:
+            "hw:cpu_policy": dedicated
+    storage_stage_configs:
+        vm_count: 1
+        target: 'volume'
+        disk_size: 10
+        io_file_size: 55
+"""
+def test_kbconfig_overide(stage_fs):
+    config_fs = {
+        'config.yaml': config_yaml
+    }
+    stage_fs('/tmp/kbtest', config_fs)
+    # verify that config override is working
+    args = ['-c', '/tmp/kbtest/config.yaml']
+    process_cli_args(args)
+    kbcfg = KBConfig()
+    kbcfg.init_with_cli()
+    kbcfg.update_configs()
+    cfg = kbcfg.config_scale
+    print(cfg.client.storage_stage_configs)
+    assert cfg.client.flavor.vcpus == 100
+    assert cfg.client.storage_stage_configs.io_file_size == 55