Some fixes and updates to README instructions

Author: vidartf

README.md

@@ -41,8 +41,20 @@ information:
   be used for both the "back-end" and "front-end" packages.
 
 After this, you will have a directory containing files used for creating a
-custom Jupyter widget. You will now be able to easily package and distribute
-your custom Jupyter widget.
+custom Jupyter widget. To check that eveything is set up as it should be,
+you should run the tests:
+
+```bash
+# First install the python package. This will also build the JS packages.
+pip install -e .
+
+# Run the python tests. This should only give you TODO errors:
+py.test
+
+# Run the JS tests. This should again, only give TODO errors (Expected 'Value' to equal 'Expected value'):
+cd ts
+npm test
+```
 
 
 ## Releasing your initial packages:
@@ -55,6 +67,9 @@ your custom Jupyter widget.
   npm login
   cd ts
   npm publish
+  # Now, you need to update the entry in /<your python package>/jlextension/package.json
+  # from "file:../../ts" to "^<the version of the NPM packge you just released>
+  # After this, run:
   cd ../<your python package>/jlextension
   npm publish
   ```

{{cookiecutter.github_project_name}}/examples/introduction.ipynb

@@ -33,7 +33,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "raise Error('TODO: Add example usage of your widget.')"
+    "raise ValueError('TODO: Add example usage of your widget.')"
    ]
   }
  ],

{{cookiecutter.github_project_name}}/setup.py

@@ -67,7 +67,7 @@
 
 setup_args = dict(
     name            = name,
-    description     = {{ cookiecutter.project_short_description }},
+    description     = '{{ cookiecutter.project_short_description }}',
     version         = version_ns['__version__'],
     scripts         = glob(pjoin('scripts', '*')),
     cmdclass        = cmdclass,

{{cookiecutter.github_project_name}}/ts/src/example.ts

@@ -50,6 +50,3 @@ class ExampleView extends DOMWidgetView {
     this.el.textContent = this.model.get('value');
   }
 }
-
-// Remove me:
-throw new Error('Implement your code');

{{cookiecutter.github_project_name}}/{{cookiecutter.python_package_name}}/__init__.py

@@ -4,7 +4,6 @@
 # Copyright (c) {{ cookiecutter.author_name }}.
 # Distributed under the terms of the Modified BSD License.
 
-from .ndarray import *
 from .example import ExampleWidget
 from ._version import *
 

{{cookiecutter.github_project_name}}/{{cookiecutter.python_package_name}}/jlextension/package.json

@@ -8,7 +8,7 @@
     "@jupyterlab/application": "~0.9.0",
     "@phosphor/coreutils": "~1.3.0",
     "@jupyter-widgets/jupyterlab-manager": "~0.25.11",
-    "{{ cookiecutter.npm_package_name }}": "^{{ cookiecutter.npm_package_version }}"
+    "{{ cookiecutter.npm_package_name }}": "file:../../ts"
   },
   "devDependencies": {
     "rimraf": "^2.6.1",