Add Black formatting check to CI

.travis.yml

@@ -24,27 +24,31 @@ env:
 
 matrix:
   include:
-  - env: PYTHON_VERSION=3.6
+  - name: "Python 3.6 - osx"
+    env: PYTHON_VERSION=3.6
     os: osx
-  - env: PYTHON_VERSION=3.6
+  - name: "Python 3.6 - linux"
+    env: PYTHON_VERSION=3.6
     os: linux
-  - env: PYTHON_VERSION=3.7
+  - name: "Python 3.7 - osx"
+    env: PYTHON_VERSION=3.7
     os: osx
-  - env: PYTHON_VERSION=3.7
+  - name: "Python 3.7 - linux"
+    env: PYTHON_VERSION=3.7
     os: linux
+  - name: "Lint"
+    env: PYTHON_VERSION=3.7
+    os: linux
+    script:
+    - black . --diff --check
 
 before_install:
-- if [[ "$PYTHON_VERSION" == "2.7" ]]; then
-      PY_MAJOR=2 ;
-  else
-      PY_MAJOR=3 ;
-  fi ;
-  if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
+- if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
       OS=Linux ;
   else
       OS=MacOSX ;
   fi ;
-  wget https://repo.continuum.io/miniconda/Miniconda$PY_MAJOR-latest-$OS-x86_64.sh -O miniconda.sh
+  wget https://repo.anaconda.com/miniconda/Miniconda3-latest-$OS-x86_64.sh -O miniconda.sh
 - bash miniconda.sh -b -p $HOME/miniconda;
 - export PATH="$HOME/miniconda/bin:$HOME/miniconda/lib:$PATH";
 - conda config --set always_yes yes --set changeps1 no;
@@ -67,4 +71,4 @@ after_success:
 
 after_failure:
 - ls /cores/core.*
-- lldb --core `ls /cores/core.*` --batch --one-line "bt"
+- lldb --core `ls /cores/core.*` --batch --one-line "bt"

README.md

@@ -123,6 +123,38 @@ You do not need to be a software developer to have a big impact on this project.
 
 It is asked that all contributions to this project be made in a respectful and considerate way. Please use the [Python Community Code of Conduct's](https://www.python.org/psf/codeofconduct/) guidelines as a reference.
 
+### Contributing code
+
+If you are going to contribute code, make sure to follow this steps:
+
+- Consider opening an issue first to discuss what you have in mind
+- Try to keep it as short and simple as possible (if you want to change several
+  things, start with just one!)
+- Fork the CadQuery repository, clone your fork and create a new branch to
+  start working on your changes
+- Start with the tests! How should CadQuery behave after your changes? Make
+  sure to add some tests to the test suite to ensure proper behavior
+- Make sure your tests have assertions checking all the expected results
+- Add a nice docstring to the test indicating what the test is doing; if there
+  is too much to explain, consider splitting the test in two!
+- Go ahead and implement the changes
+- Add a nice docstring to the functions/methods/classes you implement
+  describing what they do, what the expected parameters are and what it returns
+  (if anything)
+- Update the documentation if there is any change to the public API
+- Consider adding an example to the documentation showing your cool new
+  feature!
+- Make sure nothing is broken (run the complete test suite with `pytest`)
+- Run `black` to autoformat your code and make sure your code style complies
+  with CadQuery's
+- Push the changes to your fork and open a pull-request upstream
+- Keep an eye on the automated feedback you will receive from the CI pipelines;
+  if there is a test failing or some code is not properly formatted, you will
+  be notified without human intervention
+- Be prepared for constructive feedback and criticism!
+- Be patient and respectful, remember that those reviewing your code are also
+  working hard (sometimes reviewing changes is harder than implementing them!)
+
 ### How to Report a Bug
 When filing a bug report [issue](https://github.com/CadQuery/cadquery/issues), please be sure to answer these questions:
 

cadquery/__init__.py

@@ -1,25 +1,65 @@
 # these items point to the OCC implementation
 from .occ_impl.geom import Plane, BoundBox, Vector, Matrix
-from .occ_impl.shapes import (Shape, Vertex, Edge, Face, Wire, Solid, Shell, 
-    Compound, sortWiresByBuildOrder)
+from .occ_impl.shapes import (
+    Shape,
+    Vertex,
+    Edge,
+    Face,
+    Wire,
+    Solid,
+    Shell,
+    Compound,
+    sortWiresByBuildOrder,
+)
 from .occ_impl import exporters
 from .occ_impl import importers
 
 # these items are the common implementation
 
 # the order of these matter
-from .selectors import (NearestToPointSelector, ParallelDirSelector, 
-    DirectionSelector, PerpendicularDirSelector, TypeSelector, 
-    DirectionMinMaxSelector, StringSyntaxSelector, Selector)
+from .selectors import (
+    NearestToPointSelector,
+    ParallelDirSelector,
+    DirectionSelector,
+    PerpendicularDirSelector,
+    TypeSelector,
+    DirectionMinMaxSelector,
+    StringSyntaxSelector,
+    Selector,
+)
 from .cq import CQ, Workplane, selectors
 from . import plugins
 
 
 __all__ = [
-    'CQ', 'Workplane', 'plugins', 'selectors', 'Plane', 'BoundBox', 'Matrix', 'Vector', 'sortWiresByBuildOrder',
-    'Shape', 'Vertex', 'Edge', 'Wire', 'Face', 'Solid', 'Shell', 'Compound', 'exporters', 'importers',
-    'NearestToPointSelector', 'ParallelDirSelector', 'DirectionSelector', 'PerpendicularDirSelector',
-    'TypeSelector', 'DirectionMinMaxSelector', 'StringSyntaxSelector', 'Selector', 'plugins'
+    "CQ",
+    "Workplane",
+    "plugins",
+    "selectors",
+    "Plane",
+    "BoundBox",
+    "Matrix",
+    "Vector",
+    "sortWiresByBuildOrder",
+    "Shape",
+    "Vertex",
+    "Edge",
+    "Wire",
+    "Face",
+    "Solid",
+    "Shell",
+    "Compound",
+    "exporters",
+    "importers",
+    "NearestToPointSelector",
+    "ParallelDirSelector",
+    "DirectionSelector",
+    "PerpendicularDirSelector",
+    "TypeSelector",
+    "DirectionMinMaxSelector",
+    "StringSyntaxSelector",
+    "Selector",
+    "plugins",
 ]
 
 __version__ = "2.0.0dev"