styled-mq/src/__tests__/linearFeatures.js

import { values } from 'ramda';
import camelcase from 'camelcase';
import { LINEAR_FEATURES } from '../features';
import featureValues from './featureValues';
import { mqWithValidBreakpointsForRange } from './data';
import cssSerialiser from './helpers/cssSerialiser';

expect.addSnapshotSerializer(cssSerialiser);

describe('linear features', () => {
  const testLinearFeature = (
    name,
    validValuesMap,
    invalidValues,
    { allowNoArgument = false } = {}
  ) => {
    const validValues = values(validValuesMap);
    const methodName = camelcase(name);
    describe(`${methodName}()`, () => {
      describe('linear feature', () => {
        if (allowNoArgument) {
          it("doesn't throw if no argument is supplied", () => {
            expect(() =>
              mqWithValidBreakpointsForRange('width')[methodName]()
            ).not.toThrow();
          });

          it(`returns a valueless ${name}`, () => {
            expect(
              mqWithValidBreakpointsForRange('width')[methodName]()
            ).toMatchSnapshot();
          });
        } else {
          it('throws if no argument is supplied', () => {
            expect(() =>
              mqWithValidBreakpointsForRange('width')[methodName]()
            ).toThrowErrorMatchingSnapshot();
          });
        }

        for (const value of invalidValues) {
          it(`throws if argument is '${value}'`, () => {
            expect(() =>
              mqWithValidBreakpointsForRange('width')[methodName](value)
            ).toThrowErrorMatchingSnapshot();
          });
        }
        for (const value of validValues) {
          it(`returns the supplied ${name} for '${value}'`, () => {
            expect(
              mqWithValidBreakpointsForRange('width')[methodName](value)
            ).toMatchSnapshot();
          });
        }
      });
    });
  };

  for (const feature of LINEAR_FEATURES) {
    const { name, validValues, allowNoArgument } = feature;
    const { invalidValues } = featureValues(camelcase(name));
    testLinearFeature(name, validValues, invalidValues, { allowNoArgument });
  }
});