...

it('should do something', () => {
  expect(true).toBeTruthy();
  expect(false).toBeTruthy;
});
...

...

it('should do something', () => {
  expect(true).toBeTruthy();
  expect(false).toBeTruthy;
});
...

describe('<MyComponent />', () => {

  it('should render component', () => {
    expect(
      mount(<MyComponent />)
    )
    .toHaveLength(1);
  });



  it('should render component with given test', () => {
    expect(
      mount(<MyComponent myText="My example"/>).text()
    )
    .toEqual('My example');
  });
});

import React, { Component } from 'react'

import {
    FeatureToggleProvider
} from 'reactor-feature-toggle'

import { MyAmazingAplication } from 'some-package'

const AppWrapper = () => {
  const featureToggleData = {
    enableMainContent: true,
    enableSecondContent: false
  };

  return (
    <FeatureToggleProvider
      featureToggleService={featureToggleData}
    >
      <MyAmazingAplication />
    </FeatureToggleProvider>
  );
};

export default AppWrapper;

import React, { Component } from 'react'

import {
    FeatureToggle
} from 'reactor-feature-toggle'

const MyAmazingApplication = () => {
  return (
    <FeatureToggle featureName={'enableMainContent'} >
      <div className="content">
        <p>This content is enabled</p>
        <FeatureToggle featureName={'enableSecondContent'} >
          <p>This content is disabled</p>
        </FeatureToggle>
      </div>
    </FeatureToggle>
  );
};

export default MyAmazingApplication;

describe('<FeatureToggle />', () => {
  const aChildComponent = <div>Yay I am a child</div>;

  it('should render children if is enabled', () => {
    expect(shallow(
      <FeatureToggle
        featureName={featureNames.thisOneIsEnabled}
      >
        {aChildComponent}
      </FeatureToggle>
    )).contains(aChildComponent)).toEqual(true);
  });

  it('should NOT render children if is NOT enabled', () => {
    expect(shallow(
      <FeatureToggle
        featureName={featureNames.thisOneIsDisabled}
      >
        {aChildComponent}
      </FeatureToggle>
    )).contains(aChildComponent)).toEqual(false);
  });
});

# Running tests in parallel
# using Makefile

...
PATH      := $(PATH):node_modules/.bin
SHELL     := bash -eu -o pipefail -c
CPUS      ?= $(
    shell node -p "require('os').cpus().length" 2> /dev/null \
    || echo 1
)
MAKEFLAGS += --warn-undefined-variables --no-builtin-rules \
  --output-sync
MAKEFLAGS += --jobs $(CPUS)
...

# Running test in different 
# threads using Makefile

# Running test in different 
# threads using Jest

jest --coverage --maxWorkers=4