diff --git a/.travis.yml b/.travis.yml
index 83d257a..5cbb4fb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,7 +14,7 @@ before_install:
   - pip install pytest-cov
 
 install:
-  - pip install -e .
+  - pip install -e .[tests]
 
 script:
   - pytest --cov-report=xml --cov=datetransform tests/
diff --git a/datetransform/transform.py b/datetransform/transform.py
index fd7c8cf..5ecbb04 100644
--- a/datetransform/transform.py
+++ b/datetransform/transform.py
@@ -1,7 +1,9 @@
 import numpy as np
 import pandas as pd
 
-def add_date_features(df: pd.DataFrame, date_field_name: str, time=True):
+def add_date_features(df: pd.DataFrame, date_field_name: str, time=True, inplace=False):
+    if not inplace:
+        df = df.copy()
     make_date(df, date_field_name)
     field = df[date_field_name]
     attr = ['Year', 'Month', 'Week', 'Day', 'DayOfWeek', 'DayOfYear', 'Is_Month_End', 'Is_Month_Start',
diff --git a/setup.py b/setup.py
index 8d60e55..8696544 100644
--- a/setup.py
+++ b/setup.py
@@ -8,15 +8,15 @@ with open(path.join(this_directory, 'README.md'), encoding='utf-8') as f:
 
 
 test_requirements = [
-    'pytest'
+    'pytest>=5.4.1'
 ]
 
 setup(
     name='datetransform',
-    version='0.1.1',
+    version='0.2.0',
     packages=find_packages(),
     url='https://www.github.com/brandonschabell/datetransform',
-    download_url='https://github.com/brandonschabell/datetransform/archive/v0.1.1.tar.gz',
+    download_url='https://github.com/brandonschabell/datetransform/archive/v0.2.0.tar.gz',
     license='MIT',
     author='Brandon Schabell',
     author_email='brandonschabell@gmail.com',

Make "inplace" optional
Currently the dataframe is edited inplace. Make this an optional argument that defaults to False so a copy of the dataframe is updated.
diff --git a/tests/test_transform.py b/tests/test_transform.py
index d70f7b0..4fc4620 100644
--- a/tests/test_transform.py
+++ b/tests/test_transform.py
@@ -4,7 +4,6 @@ from datetransform import transform
 
 
 def test_add_date_features():
-
     df = pd.DataFrame({'dateCol': ['2019-08-09 16:39:47']})
     df = transform.add_date_features(df, 'dateCol')
     assert df.columns.tolist() == ['dateCol',
@@ -23,3 +22,30 @@ def test_add_date_features():
                                    'dateColHour',
                                    'dateColMinute',
                                    'dateColSecond']
+
+
+def test_inplace_transform():
+    df = pd.DataFrame({'dateCol': ['2019-08-09 16:39:47']})
+    transform.add_date_features(df, 'dateCol', inplace=True)
+    assert df.columns.tolist() == ['dateCol',
+                                   'dateColYear',
+                                   'dateColMonth',
+                                   'dateColWeek',
+                                   'dateColDay',
+                                   'dateColDayOfWeek',
+                                   'dateColDayOfYear',
+                                   'dateColIsMonthEnd',
+                                   'dateColIsMonthStart',
+                                   'dateColIsQuarterEnd',
+                                   'dateColIsQuarterStart',
+                                   'dateColIsYearEnd',
+                                   'dateColIsYearStart',
+                                   'dateColHour',
+                                   'dateColMinute',
+                                   'dateColSecond']
+
+
+def test_not_inplace_transform():
+    df = pd.DataFrame({'dateCol': ['2019-08-09 16:39:47']})
+    transform.add_date_features(df, 'dateCol')
+    assert df.columns.tolist() == ['dateCol']
\ No newline at end of file

pip install -e .[dev]
parse_log_pytest
pytest
numpy>=1.16.0 pandas>=1.0.0 pytest
apt-get update apt-get install -y gcc
3.7
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
attrs @ file:///croot/attrs_1668696182826/work
certifi @ file:///croot/certifi_1671487769961/work/certifi
-e git+https://github.com/brandonschabell/datetransform.git@33b75b1948cad92aa4edf91850887f27562b0632#egg=datetransform
flit_core @ file:///opt/conda/conda-bld/flit-core_1644941570762/work/source/flit_core
importlib-metadata @ file:///tmp/build/80754af9/importlib-metadata_1648562407465/work
iniconfig @ file:///home/linux1/recipes/ci/iniconfig_1610983019677/work
numpy==1.21.6
packaging @ file:///croot/packaging_1671697413597/work
pandas==1.3.5
pluggy @ file:///tmp/build/80754af9/pluggy_1648042572264/work
py @ file:///opt/conda/conda-bld/py_1644396412707/work
pytest==7.1.2
python-dateutil==2.9.0.post0
pytz==2025.2
six==1.17.0
tomli @ file:///opt/conda/conda-bld/tomli_1657175507142/work
typing_extensions @ file:///croot/typing_extensions_1669924550328/work
zipp @ file:///croot/zipp_1672387121353/work

name: datetransform
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - attrs=22.1.0=py37h06a4308_0
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2022.12.7=py37h06a4308_0
  - flit-core=3.6.0=pyhd3eb1b0_0
  - importlib-metadata=4.11.3=py37h06a4308_0
  - importlib_metadata=4.11.3=hd3eb1b0_0
  - iniconfig=1.1.1=pyhd3eb1b0_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - packaging=22.0=py37h06a4308_0
  - pip=22.3.1=py37h06a4308_0
  - pluggy=1.0.0=py37h06a4308_1
  - py=1.11.0=pyhd3eb1b0_0
  - pytest=7.1.2=py37h06a4308_0
  - python=3.7.16=h7a1cb2a_0
  - readline=8.2=h5eee18b_0
  - setuptools=65.6.3=py37h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - tomli=2.0.1=py37h06a4308_0
  - typing_extensions=4.4.0=py37h06a4308_0
  - wheel=0.38.4=py37h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zipp=3.11.0=py37h06a4308_0
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - numpy==1.21.6
      - pandas==1.3.5
      - python-dateutil==2.9.0.post0
      - pytz==2025.2
      - six==1.17.0
prefix: /opt/conda/envs/datetransform

tests/test_transform.py::test_inplace_transform tests/test_transform.py::test_not_inplace_transform
tests/test_transform.py::test_add_date_features
datetransform/transform.py .travis.yml setup.py
datetransform/transform.py .travis.yml setup.py