reactComponentExpect.js

/**
 * Copyright 2013-2014, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule reactComponentExpect
 * @nolint
 */

"use strict";

var ReactTestUtils = require('ReactTestUtils');

var assign = require('Object.assign');

function reactComponentExpect(instance) {
  if (instance instanceof reactComponentExpect) {
    return instance;
  }

  if (!(this instanceof reactComponentExpect)) {
    return new reactComponentExpect(instance);
  }

  this._instance = instance;
  expect(typeof instance).toBe('object');
  expect(typeof instance.constructor).toBe('function');
  expect(ReactTestUtils.isElement(instance)).toBe(false);
}

assign(reactComponentExpect.prototype, {
  // Getters -------------------------------------------------------------------

  /**
   * @instance: Retrieves the backing instance.
   */
  instance: function() {
    return this._instance;
  },

  /**
   * There are two types of components in the world.
   * - A component created via React.createClass() - Has a single child
   *   subComponent - the return value from the .render() function. This
   *   function @subComponent expects that this._instance is component created
   *   with React.createClass().
   * - A primitive DOM component - which has many renderedChildren, each of
   *   which may have a name that is unique with respect to its siblings. This
   *   method will fail if this._instance is a primitive component.
   *
   * TL;DR: An instance may have a subComponent (this._renderedComponent) or
   * renderedChildren, but never both. Neither will actually show up until you
   * render the component (simply instantiating is not enough).
   */
  expectRenderedChild: function() {
    this.toBeCompositeComponent();
    return new reactComponentExpect(this.instance()._renderedComponent);
  },

  /**
   * The nth child of a DOMish component instance that is not falsy.
   */
  expectRenderedChildAt: function(childIndex) {
    // Currently only dom components have arrays of children, but that will
    // change soon.
    this.toBeDOMComponent();
    var renderedChildren = this.instance()._renderedChildren || {};
    for (var name in renderedChildren) {
      if (!renderedChildren.hasOwnProperty(name)) {
        continue;
      }
      if (renderedChildren[name]) {
        if (renderedChildren[name]._mountIndex === childIndex) {
          return new reactComponentExpect(renderedChildren[name]);
        }
      }
    }
    throw new Error('Child:' + childIndex + ' is not found');
  },

  toBeDOMComponentWithChildCount: function(n) {
    this.toBeDOMComponent();
    expect(this.instance()._renderedChildren).toBeTruthy();
    var len = Object.keys(this.instance()._renderedChildren).length;
    expect(len).toBe(n);
    return this;
  },

  toBeDOMComponentWithNoChildren: function() {
    this.toBeDOMComponent();
    expect(this.instance()._renderedChildren).toBeFalsy();
    return this;
  },

  // Matchers ------------------------------------------------------------------

  toBeComponentOfType: function(convenienceConstructor) {
    var type = typeof convenienceConstructor === 'string' ?
               convenienceConstructor :
               convenienceConstructor.type;
    expect(
      this.instance()._currentElement.type === type
    ).toBe(true);
    return this;
  },

  /**
   * A component that is created with React.createClass. Just duck typing
   * here.
   */
  toBeCompositeComponent: function() {
    expect(
      typeof this.instance().render === 'function' &&
      typeof this.instance().setState === 'function'
    ).toBe(true);
    return this;
  },

  toBeCompositeComponentWithType: function(convenienceConstructor) {
    this.toBeCompositeComponent();
    expect(
      this.instance()._currentElement.type === convenienceConstructor.type
    ).toBe(true);
    return this;
  },

  toBeTextComponent: function() {
    expect(ReactTestUtils.isTextComponent(this.instance())).toBe(true);
    return this;
  },

  toBePresent: function() {
    expect(this.instance()).toBeTruthy();
    return this;
  },

  /**
   * A terminal type of component representing some virtual dom node. Just duck
   * typing here.
   */
  toBeDOMComponent: function() {
    expect(ReactTestUtils.isDOMComponent(this.instance())).toBe(true);
    return this;
  },

  /**
   * @deprecated
   * @see toBeComponentOfType
   */
  toBeDOMComponentWithTag: function(tag) {
    this.toBeDOMComponent();
    expect(this.instance().tagName).toBe(tag.toUpperCase());
    return this;
  },

  /**
   * Check that internal state values are equal to a state of expected values.
   */
  scalarStateEqual: function(stateNameToExpectedValue) {
    expect(this.instance()).toBeTruthy();
    for (var stateName in stateNameToExpectedValue) {
      if (!stateNameToExpectedValue.hasOwnProperty(stateName)) {
        continue;
      }
      expect(this.instance().state[stateName])
        .toEqual(stateNameToExpectedValue[stateName]);
    }
    return this;
  },

  /**
   * Check a set of props are equal to a set of expected values - only works
   * with scalars.
   */
  scalarPropsEqual: function(propNameToExpectedValue) {
    expect(this.instance()).toBeTruthy();
    for (var propName in propNameToExpectedValue) {
      if (!propNameToExpectedValue.hasOwnProperty(propName)) {
        continue;
      }
      expect(this.instance().props[propName])
        .toEqual(propNameToExpectedValue[propName]);
    }
    return this;
  },

  /**
   * Check a set of props are equal to a set of expected values - only works
   * with scalars.
   */
  scalarContextEqual: function(contextNameToExpectedValue) {
    expect(this.instance()).toBeTruthy();
    for (var contextName in contextNameToExpectedValue) {
      if (!contextNameToExpectedValue.hasOwnProperty(contextName)) {
        continue;
      }
      expect(this.instance().context[contextName])
        .toEqual(contextNameToExpectedValue[contextName]);
    }
    return this;
  }
});

module.exports = reactComponentExpect;