Integrated chai-subset and added assert-based negation to containSu…

…bset

lib/chai/core/assertions.js

@@ -8,6 +8,7 @@
 import {Assertion} from '../assertion.js';
 import {AssertionError} from 'assertion-error';
 import * as _ from '../utils/index.js';
+import {config} from '../config.js';
 
 const {flag} = _;
 
@@ -4061,3 +4062,89 @@ Assertion.addProperty('finite', function (msg) {
     'expected #{this} to not be a finite number'
   );
 });
+
+/**
+ * A subset-aware compare function
+ *
+ * @param {unknown} expected
+ * @param {unknown} actual
+ * @returns {void}
+ */
+function compareSubset(expected, actual) {
+  if (expected === actual) {
+    return true;
+  }
+  if (typeof actual !== typeof expected) {
+    return false;
+  }
+  if (typeof expected !== 'object' || expected === null) {
+    return expected === actual;
+  }
+  if (!!expected && !actual) {
+    return false;
+  }
+
+  if (Array.isArray(expected)) {
+    if (typeof actual.length !== 'number') {
+      return false;
+    }
+    var aa = Array.prototype.slice.call(actual);
+    return expected.every(function (exp) {
+      return aa.some(function (act) {
+        return compareSubset(exp, act);
+      });
+    });
+  }
+
+  if (expected instanceof Date) {
+    if (actual instanceof Date) {
+      return expected.getTime() === actual.getTime();
+    } else {
+      return false;
+    }
+  }
+
+  return Object.keys(expected).every(function (key) {
+    var eo = expected[key];
+    var ao = actual[key];
+    if (typeof eo === 'object' && eo !== null && ao !== null) {
+      return compareSubset(eo, ao);
+    }
+    if (typeof eo === 'function') {
+      return eo(ao);
+    }
+    return ao === eo;
+  });
+}
+
+/**
+ * ### .containSubset
+ *
+ * Asserts that the target primitive/object/array structure deeply contains all provided fields
+ * at the same key/depth as the provided structure.
+ *
+ * When comparing arrays, the target must contain the subset of at least one of each object/value in the subset array.
+ * Order does not matter.
+ *
+ *     expect({name: {first: "John", last: "Smith"}}).to.containSubset({name: {first: "John"}});
+ *
+ * Add `.not` earlier in the chain to negate the assertion. This will cause the assertion to fail
+ * only if the target DOES contains the provided data at the expected keys/depths.
+ *
+ * @name containSubset
+ * @namespace BDD
+ * @public
+ */
+Assertion.addMethod('containSubset', function (expected) {
+  const actual = _.flag(this, 'object');
+  const showDiff = config.showDiff;
+
+  this.assert(
+    compareSubset(expected, actual),
+    'expected #{act} to contain subset #{exp}',
+    'expected #{act} to not contain subset #{exp}',
+    expected,
+    actual,
+    showDiff
+  );
+});

lib/chai/interface/assert.js

@@ -3157,6 +3157,48 @@ assert.isNotEmpty = function (val, msg) {
   new Assertion(val, msg, assert.isNotEmpty, true).to.not.be.empty;
 };
 
+/**
+ * ### .containsSubset(target, subset)
+ *
+ * Asserts that the target primitive/object/array structure deeply contains all provided fields
+ * at the same key/depth as the provided structure.
+ *
+ * When comparing arrays, the target must contain the subset of at least one of each object/value in the subset array.
+ * Order does not matter.
+ *
+ *     assert.containsSubset(
+ *         [{name: {first: "John", last: "Smith"}}, {name: {first: "Jane", last: "Doe"}}],
+ *         [{name: {first: "Jane"}}]
+ *     );
+ *
+ * @name containsSubset
+ * @alias containSubset
+ * @param {unknown} val
+ * @param {unknown} exp
+ * @param {string} msg _optional_
+ * @namespace Assert
+ * @public
+ */
+assert.containsSubset = function (val, exp, msg) {
+  new Assertion(val, msg).to.containSubset(exp);
+};
+
+/**
+ * ### .doesNotContainSubset(target, subset)
+ *
+ * The negation of assert.containsSubset.
+ *
+ * @name doesNotContainSubset
+ * @param {unknown} val
+ * @param {unknown} exp
+ * @param {string} msg _optional_
+ * @namespace Assert
+ * @public
+ */
+assert.doesNotContainSubset = function (val, exp, msg) {
+  new Assertion(val, msg).to.not.containSubset(exp);
+};
+
 /**
  * Aliases.
  *
@@ -3176,4 +3218,7 @@ assert.isNotEmpty = function (val, msg) {
 )('isFrozen', 'frozen')('isNotFrozen', 'notFrozen')('isEmpty', 'empty')(
   'isNotEmpty',
   'notEmpty'
-)('isCallable', 'isFunction')('isNotCallable', 'isNotFunction');
+)('isCallable', 'isFunction')('isNotCallable', 'isNotFunction')(
+  'containsSubset',
+  'containSubset'
+);

test/subset.js

@@ -0,0 +1,206 @@
+import {assert, expect} from '../index.js';
+
+describe('plain object', function () {
+  var testedObject = {
+    a: 'b',
+    c: 'd'
+  };
+
+  it('should pass for smaller object', function () {
+    expect(testedObject).to.containSubset({
+      a: 'b'
+    });
+  });
+
+  it('should pass for same object', function () {
+    expect(testedObject).to.containSubset({
+      a: 'b',
+      c: 'd'
+    });
+  });
+
+  it('should pass for similar, but not the same object', function () {
+    expect(testedObject).to.not.containSubset({
+      a: 'notB',
+      c: 'd'
+    });
+  });
+});
+
+describe('complex object', function () {
+  var testedObject = {
+    a: 'b',
+    c: 'd',
+    e: {
+      foo: 'bar',
+      baz: {
+        qux: 'quux'
+      }
+    }
+  };
+
+  it('should pass for smaller object', function () {
+    expect(testedObject).to.containSubset({
+      a: 'b',
+      e: {
+        foo: 'bar'
+      }
+    });
+  });
+
+  it('should pass for smaller object', function () {
+    expect(testedObject).to.containSubset({
+      e: {
+        foo: 'bar',
+        baz: {
+          qux: 'quux'
+        }
+      }
+    });
+  });
+
+  it('should pass for same object', function () {
+    expect(testedObject).to.containSubset({
+      a: 'b',
+      c: 'd',
+      e: {
+        foo: 'bar',
+        baz: {
+          qux: 'quux'
+        }
+      }
+    });
+  });
+
+  it('should pass for similar, but not the same object', function () {
+    expect(testedObject).to.not.containSubset({
+      e: {
+        foo: 'bar',
+        baz: {
+          qux: 'notAQuux'
+        }
+      }
+    });
+  });
+
+  it('should fail if comparing when comparing objects to dates', function () {
+    expect(testedObject).to.not.containSubset({
+      e: new Date()
+    });
+  });
+});
+
+describe('circular objects', function () {
+  var object = {};
+
+  before(function () {
+    object.arr = [object, object];
+    object.arr.push(object.arr);
+    object.obj = object;
+  });
+
+  it('should contain subdocument', function () {
+    expect(object).to.containSubset({
+      arr: [{arr: []}, {arr: []}, [{arr: []}, {arr: []}]]
+    });
+  });
+
+  it('should not contain similar object', function () {
+    expect(object).to.not.containSubset({
+      arr: [{arr: ['just random field']}, {arr: []}, [{arr: []}, {arr: []}]]
+    });
+  });
+});
+
+describe('object with compare function', function () {
+  it('should pass when function returns true', function () {
+    expect({a: 5}).to.containSubset({a: (a) => a});
+  });
+
+  it('should fail when function returns false', function () {
+    expect({a: 5}).to.not.containSubset({a: (a) => !a});
+  });
+
+  it('should pass for function with no arguments', function () {
+    expect({a: 5}).to.containSubset({a: () => true});
+  });
+});
+
+describe('comparison of non objects', function () {
+  it('should fail if actual subset is null', function () {
+    expect(null).to.not.containSubset({a: 1});
+  });
+
+  it('should fail if expected subset is not a object', function () {
+    expect({a: 1}).to.not.containSubset(null);
+  });
+
+  it('should not fail for same non-object (string) variables', function () {
+    expect('string').to.containSubset('string');
+  });
+});
+
+describe('assert style of test', function () {
+  it('should find subset', function () {
+    assert.containsSubset({a: 1, b: 2}, {a: 1});
+    assert.containSubset({a: 1, b: 2}, {a: 1});
+  });
+
+  it('negated assert style should function', function () {
+    assert.doesNotContainSubset({a: 1, b: 2}, {a: 3});
+  });
+});
+
+describe('comparison of dates', function () {
+  it('should pass for the same date', function () {
+    expect(new Date('2015-11-30')).to.containSubset(new Date('2015-11-30'));
+  });
+
+  it('should pass for the same date if nested', function () {
+    expect({a: new Date('2015-11-30')}).to.containSubset({
+      a: new Date('2015-11-30')
+    });
+  });
+
+  it('should fail for a different date', function () {
+    expect(new Date('2015-11-30')).to.not.containSubset(new Date('2012-02-22'));
+  });
+
+  it('should fail for a different date if nested', function () {
+    expect({a: new Date('2015-11-30')}).to.not.containSubset({
+      a: new Date('2012-02-22')
+    });
+  });
+
+  it('should fail for invalid expected date', function () {
+    expect(new Date('2015-11-30')).to.not.containSubset(
+      new Date('not valid date')
+    );
+  });
+
+  it('should fail for invalid actual date', function () {
+    expect(new Date('not valid actual date')).to.not.containSubset(
+      new Date('not valid expected date')
+    );
+  });
+});
+
+describe('cyclic objects', () => {
+  it('should pass', () => {
+    const child = {};
+    const parent = {
+      children: [child]
+    };
+    child.parent = parent;
+
+    const myObject = {
+      a: 1,
+      b: 'two',
+      c: parent
+    };
+    expect(myObject).to.containSubset({
+      a: 1,
+      c: parent
+    });
+  });
+});