Updated README with development instructions

* Additionally the `setup.py` file is simplified.
* Tests automatically enforce `flake8` by using the `pytest-flake8`
plugin.

.gitignore

@@ -4,7 +4,7 @@
 *.so
 
 # Packages
-*.egg
+*.eggs
 *.egg-info
 dist
 build
@@ -18,6 +18,12 @@ develop-eggs
 lib
 lib64
 
+# Virtualenv
+env
+.env
+venv
+.venv
+
 # Installer logs
 pip-log.txt
 

.travis.yml

@@ -11,5 +11,4 @@ python:
 install: pip install -e .[yaml,toml,tests,xml]
 
 script:
-  - pytest -v
-  - flake8 jinja2cli tests
+  - pytest -vvv

README.md

@@ -43,6 +43,26 @@ If `xmltodict` is present, you can use XML as an input data source.
 
 `$ pip install jinja2-cli[xml]`
 
+## Development
+For local development install the package in develop mode with `tests` extras
+into a virtualenv:
+
+```console
+$ python -m venv env
+$ env/bin/activate
+(env) $ pip install -e ".[tests]"
+```
+
+### Code style
+The project uses `flake8` to check the code style.
+
+### Tests
+To invoke tests (and code style checks) run the `pytest` command:
+
+```console
+(env) $ pytest
+```
+
 ## TODO
  * Variable inheritance and overrides
   * Tests!

jinja2cli/cli.py

@@ -6,13 +6,11 @@
 """
 
 import warnings
-
-warnings.filterwarnings("ignore")
-
 import os
 import sys
 from optparse import Option, OptionParser
 
+warnings.filterwarnings("ignore")
 sys.path.insert(0, os.getcwd())
 
 PY3 = sys.version_info[0] == 3

setup.cfg

@@ -4,3 +4,8 @@ max-line-length = 100
 
 [bdist_wheel]
 universal = 1
+
+[tool:pytest]
+addopts = --flake8
+flake8-max-line-length = 100
+flake8-ignore = E402

setup.py

@@ -14,7 +14,7 @@
 from setuptools import find_packages, setup
 
 install_requires = ["jinja2"]
-tests_requires = ["pytest", "flake8"]
+tests_require = ["pytest", "flake8"]
 
 setup(
     name="jinja2-cli",
@@ -29,12 +29,11 @@
     license="BSD",
     install_requires=install_requires,
     extras_require={
-        "yaml": install_requires + ["pyyaml"],
-        "toml": install_requires + ["toml"],
-        "xml": install_requires + ["xmltodict"],
-        "tests": install_requires + tests_requires,
+        "yaml": ["pyyaml"],
+        "toml": ["toml"],
+        "xml": ["xmltodict"],
+        "tests": tests_require,
     },
-    tests_require=tests_requires,
     include_package_data=True,
     entry_points={"console_scripts": ["jinja2 = jinja2cli:main"]},
     classifiers=[