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Package for aiding the development of JavaScript code to be provided as part of Python packages through integration with Node.js development tools into a Python environment via the Calmjs framework.

Project description

Package for aiding the development of JavaScript code to be provided as part of Python packages through integration with Node.js development tools into a Python environment via the Calmjs framework.


Python packages can contain arbitrary resource files, which can include JavaScript sources. This situation is commonly found in packages that provide frontend functionalities that enhance user experience that require interactions with a related backend Python code running on the server provided by the given package. In order to facilitate the testing of those JavaScript code from those Python packages, commonly Node.js packages and frameworks are often used to achieve this.

Typically, for the management of this dependency, this often require two or more separate package management systems that are not properly aware of each other, resulting in often cumbersome linkage or needless duplication of packages installed on a given system. Moreover, the configurations files for the Node.js/JavaScript package dependencies, along with the building of artifacts and testing of the JavaScript provided by those Python packages are very specific to the given project and generally not portable. If multiple such packages are required for a downstream Python project, the scripts and definition files for building of artifacts and testing generally have to be manually modified, which is often a very aggravating and error-prone process.

The Calmjs framework, however, provides the means for Python packages to declare the JavaScript modules they are to export, and this package,, provides the means to consume those information such that the JavaScript tests declared within those Python packages can be executed without having to manually construct and verify the paths to the source and tests files, no matter where they are within the environment, provided they are properly declared through the Calmjs framework. The tests can then run either against the JavaScript sources provided by the Python package through the artifact generation framework, or against prebuilt artifacts that contain those functionalities. Naturally, the support for the artifact generation framework requires integration with the Calmjs framework. Currently, generation of AMD artifacts is supported using the calmjs.rjs, and the generation of webpack artifacts supported through the calmjs.webpack package.


  • Provides a set of commonly used development tools that are commonly used for testing JavaScript code. In brief, these include:


    Test runner for running tests included with packages against the JavaScript code contained there.


    A JavaScript test framework for writing unit tests for node.js or the browser.


    A headless webkit with JavaScript API capable of interfacing with karma; this enables the running of integration JavaScript tests.


    A set of spies, stubs and mocks for JavaScript, for working with unit testing frameworks.

    Plus other integration packages that get them to work with each other, namely the various karma-* packages for integration with karma. For full details on the environment that will be installed through the calmjs framework, the command calmjs npm can be invoked to view the package.json once this package is installed into a Python environment. For installation, please refer to the following section.

  • Through the use of the calmjs module registry system, Python packages can declare JavaScript sources that can be passed through specific toolchains that build them into deployable artifacts. The package provide a common framework for the generation of configuration files for the execution of tests through the karma test runner.

    The usage of this is typically through the calmjs runtime system.


As the goal of is to integrate Node.js development tools into a Python environment, both Node.js and npm are required to be available within the target installation environment; if they are not installed please follow the installation steps for Node.js appropriate for the target operating system/environment/platform.

Naturally, since this is achieved through calmjs, it will need to be available in the target installation environment; however, this is achieved simply by installing through pip from PyPI.

$ pip install

Alternative installation methods (for developers, advanced users)

Development is still ongoing with, for the latest features and bug fixes, the development version may be desirable. However, in order for the source installation to function correctly, the calmjs package must be available in the current environment for all the package metadata be correctly generated. With recent versions of pip and setuptools that correctly support the setup_requires keyword, the following command should ensure that calmjs be available before pip attempts to set up this package. The latest development version of this package may be installed using:

$ pip install git+

Or alternatively, clone the git repository manually and run the command manually, e.g.:

$ git clone
$ cd
$ pip install -e .

Failing to have calmjs be available before the source installation of will result in the critical Node.js dependencies not being defined correctly for this package. This may be corrected by regenerating them using the following at the root of this source based installation:

$ python egg_info

If no error message that indicate the failure to usage of certain keywords, run the tests (documented in the next section) to be sure that the package is functioning correctly.

Installation of Node.js external dependencies

As this package integrates a number of Node.js packages to achieve the intended functionality of integration with that environment, Node.js packages required by this package can be installed into the current working directory through the calmjs executable with the included npm command:

$ calmjs npm --install

Testing the installation

Finally, to verify for the successful installation of, the included tests may be executed through this command:

$ python -m unittest

However, if the steps to install external Node.js dependencies to the current directory was followed, the current directory may be specified as the CALMJS_TEST_ENV environment variable. Under POSIX compatible shells this may be executed instead from within that directory:

$ CALMJS_TEST_ENV=. python -m unittest

Do note a number of failures during execution of Karma may appear; this is normal as these are tests that involve the simulation of failures to ensure proper error handling on real test failures.


This package provides features that may be used as part of the calmjs runtime, be used in conjunction with toolchains that already provide integration with the underlying toolchain for this package (which also implies that toolchain developers are provided the ability build these integration), and finally, a way for package developers to make use of these features to quickly set up their package for testing of their JavaScript sources in conjunction with these toolchains.

The default tool is meant to provide a calmjs runtime that is injected before a calmjs toolchain runtime that is responsible for the generation of deployable artifacts, such as AMD bundles (through RequireJS) or webpack bundles (through webpack). Typically, this package is used in conjunction with the respective integration packages (e.g. calmjs.rjs and calmjs.webpack). Those specific packages will have additional instructions on how they make use of this package, such as the instructions on how to create the entry points to support the testing of artifacts using the calmjs artifact karma command that is provided by this package.

With RequireJS

For instance, a developer might execute the r.js tool through calmjs.rjs for creation of an AMD bundle from their Python project using a command such as:

$ calmjs rjs example.package

The above command would package all the JavaScript code provided by the Python package example.package into an AMD bundle artifact through r.js. As the example.package may also provide tests for its JavaScript code (naturally written in JavaScript), it may be executed through the karma test runner provided by the selected package. The command is as simple as adding karma before the toolchain runtime, like:

$ calmjs karma rjs example.package

This would apply a test advice to the rjs toolchain runtime and invoke it. Normally, before the bundling is done, the tests will be executed against the transpiled sources in the build directory. Note that the test advice is also implemented by calmjs.rjs to ensure that this testing workflow is properly integrated.

With webpack

Likewise for calmjs.webpack, where its support for webpack is also provided through a similar mechanism such that the following command will execute the tests for the package through the typical webpack method of karma invocation:

$ calmjs karma webpack example.package

Skip artifact building

If the generation of the artifact or bundle file after testing concludes (whether success or failure) is not desired, the -T or the --only-test flag may be applied to the karma command like so:

$ calmjs karma -T webpack example.package
$ calmjs karma --only-test rjs example.package

Easily test the generated bundle artifact using existing tests

To run tests against pre-generated artifact files, provides a surrogate toolchain runtime specific for the karma command that may be used to achieve this purpose. For example, given an artifact file (e.g. bundle.js), it is possible to test whether it correctly included JavaScript code generated/provided by example.package using tests provided by the same package with the following command:

$ calmjs karma run \
    --artifact=bundle.js \

However, for more complicated toolchains and packages this will probably not work, as the generation of these artifacts typically involve extra optional advices that have been added. To address that, one may apply the --toolchain-package flag which serves a similar purpose as the --optional-advice flag for certain toolchains. For calmjs.rjs, this is necessary. The full command may be like so:

$ calmjs karma run \
    --artifact=bundle.js \
    --test-with-package=example.package \

Likewise for webpack; if the selected artifact file is generated through calmjs webpack, it may be tested using the following:

$ calmjs karma run \
    --artifact=bundle.js \
    --test-with-package=example.package \

As with all calmjs tools, more help can be acquired by appending -h or --help to each of the runtime commands, i.e. calmjs karma -h or calmjs karma run -h. Replacing the -h flag with -V will report the version information for the underlying packages associated with the respective runtime used.

More on testing in conjunction with artifacts

The --artifact flag can also be specified directly on the karma runner; this has the consequence of enabling the testing of limited or explicitly mapped JavaScript sources exported by specific Python modules. What this means is that instead of building and testing all the dependency modules along with a given module, all those dependencies can be applied to the test environment as a separate, complete artifact. This has the effect of removing the dependency sources from the build directory such that coverage report no longer shows up, with the bonus of also testing the artifact whether or not the it is compatible with the sources being tested. An example with the nunja.stock package which requires nunja:

$ calmjs rjs nunja
$ calmjs karma --coverage --artifact=nunja.js --cover-test \
    rjs nunja.stock --sourcepath-method=explicit

The first command produces the artifact file nunja.js, which is then immediately used by the subsequent command which explicitly filters out all other sources not specified. Otherwise, the standard way is that the dependencies will also be included into the test and the resulting artifact file. The --cover-test flag denotes that the test coverage reporting should be extended to the tests provided. Similarly, enabling the --cover-artifact flag will extend coverage reporting to the artifacts included for the test run.

Testing of prebuilt artifacts defined for packages

Package level artifacts defined and generated through the tools that make use of the calmjs.artifacts registry system may be tested using the calmjs artifact karma tool if the artifact entry in the calmjs.artifacts registry also has a corresponding entry in the calmjs.artifacts.tests registry. Typically, the module that the entry point references for the artifact entry will be documented by the toolchain package that supplied the builder entry. If the artifacts in the package to be tested are created and the package has well-defined entries suitable for testing purpose, the following command may be executed to test the defined and generated artifacts:

$ calmjs artifact karma example.package

There are cases where the test execution may require sourcing tests from other packages; this use case is especially valid for dependent packages where their developer want to ensure that the changes they may have made to their dependencies through the extensions they developed and provided by their packages have no negative impact to existing functionality. This functionality is implemented by the --test-with-package flag, which may be used to specify which package the artifact should source the tests from.

$ calmjs artifact karma example.package \
    --test-with-package example.dependent

The above command will use karma to execute tests provided by the example.dependent package against the artifacts defined for example.package. If the artifacts were correctly built, with no new code breaking existing functionality that was provided by the example.dependent package, all tests should pass.

Note that --test-with-package flag overrides the list of source packages that will provide the tests to be tested against the artifact.

If additional artifacts are required before the inclusion of the package artifact into the test runner (e.g. testing for possible conflicts that artifacts may introduce to the package artifact), they may be specified using the --artifact flag; specified artifacts will be prepended to the list of artifacts provided by the builder for the test execution.


The following may be some issues that may be encountered with standard or typical usage of

Error: No provider for “framework:mocha”! (Resolving: framework:mocha)

The most likely cause of this error is that the npm dependencies specified for this package is not available for the current Node.js environment. Please ensure that is installed before trying again. One method is to prepend to the calmjs npm install command, e.g:

$ calmjs npm --install ...

Alternatively, package developers can have extras that requires this package, and instruct downstream users interested in the development of that package to install and use the package with that extras flag enabled. For instance, nunja has the support for that:

$ calmjs npm --install nunja[dev]

ERROR [plugin]: “karma-…” plugin: …

A message specific to some plugin may result in the test runner not being able to execute any test. This is typically caused by certain versions of karma test runner not being able to cleanly deal with misbehaving plugins that is available in the node_modules directory. If the plugin shown inside the quote (starting with karma-) is unnecessary for the execution of tests, it should be removed and the test command should be executed again.

UserWarning: Unknown distribution option: ‘package_json’

Installation using the development method will show the above message if calmjs was not already installed into the current environment. Please either reinstall, or regenerate the metadata by running:

$ python egg_info

In the root of the source directory to ensure correct behavior of this package.


2.3.0 (2019-05-28)

  • Provide the -T or --test-only flag to the karma runtime to allow toolchain execution be terminated after the tests are executed regardless of outcome. This would generally allow the test to run without forcing the toolchain to build the artifact. [ #11 ]

2.2.2 (2018-08-17)

  • Configuration writers that write out karma configuration scripts that import other Node.js modules that are present within the environment that the karma binary reside in should no longer encounter a Error: Cannot find module message. [ #10 ]
  • Permit the use of other karma_conf dict/mapping types in the spec. [ #9 ]

2.2.1 (2018-08-01)

  • Allow the karma configuration writer to be specified in the spec, such that it may be overridden by framework integration packages. [ #8 ]

2.2.0 (2018-07-24)

  • Support the correct resolution of test child module registries, which was introduced in calmjs-3.3.0. [ #6 ]
  • Ensure that a missing karma binary is also correctly dealt with by the same set of exception and flags. [ #7 ]

2.1.0 (2018-05-28)

  • Ensure the exit code indicates failure if the artifact test entry point references an import that cannot be resolved (failure to set up the test must result in a failure). [ #3 ]
  • Make use of the corrected semantics provided by calmjs-3.1.0 for the deferred export location verification, which also silences the calmjs-4.0.0 deprecation warning. [ #5 ]

2.0.0 (2018-01-10)

  • Migration to the calmjs-3.0.0 API.
  • Bumped a number of dependencies on Node.js packages.
  • The paths that are covered by the test coverage report are now recorded in the Spec as part of the test execution workflow through the KarmaDriver.
  • Provide framework and command for testing of predefined artifacts generated for packages defined through the calmjs.artifacts registry; calmjs.artifacts.tests registry was created such that toolchain packages may declare the test compliment builder functions to facilitate testing for their dependent packages.
  • Implemented --cover-report-type flag to support the specification of multiple coverage report types to be generated, and ensured that the defined report types actually work (a karma/istanbul bug was found and a workaround was implemented).
  • A number of internal code refactor, i.e. a number of internal API changes have happened.
  • Deprecated --coverage-type flag, as it is inconsistently named and that features provided by --cover-report-type superseded this.
  • Deprecated --test-package flag in favor of --test-with-package for more clarity about the intention of that flag.

1.1.0 (2017-08-10)

  • Tests are now automatically wrapped by a default template when served by karma to better limit the scope of the variables defined within each file. This can be disabled using --no-wrap-tests flag on the karma runtime.

1.0.3 (2017-05-22)

  • Move the --artifact and --cover-artifact flag up to the main karma runtime to permit wider and more flexible usage for all runners.
  • Correctly report the path of missing specified artifacts in the logs.

1.0.2 (2017-01-27)

  • Provide test prefix key and constant.

1.0.1 (2016-11-30)

  • Correct the inability to launch standard graphical browsers directly via the runner under Windows.

1.0.0 (2016-11-18)

  • Initial release of the development support for the calmjs framework.
  • Include karma test runner integration as a calmjs runtime that can accept calmjs toolchain runtimes to facilitate testing.
  • Generation of test coverage reports of JavaScript sources executed.
  • Leverage the toolchain advice system for adding the test runner and also permit the modification of test configurations by toolchain implementations that require specific instructions for a successful execution of tests.
  • Permit integration with other packages for testing artifacts generated by other systems.

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