[refactor] Migrate from Mocha+Chai to Jest (#6079)

* [refactor] Migrate from Mocha+Chai to Jest

This change migrates all the existing unit tests
- to Jest's global expect and matchers from chai's imported expect, asserts and matchers.
- to Jest's describe/test from mocha's describe/it

The majority of the mechanical changes to tests are achieved through running jest-codemods. The only two note-worthy manual tweaks:
1. Setting a testURL of http://localhost in jest config and adjusting a few tests to leverage this value instead of relying on about:blank.
2. Re-enabling ExploreChartPanel_spec which was previously commented out as we cannot have empty tests with nothing in it with Jest. :)

This change also removes dependencies to Mocha and Chai.

* Remove the test:one command as it now does the same thing as test.

* Fixing lint errors. The diff looks large but is large done through `yarn run lint --fix`

The only noteworthy change is the one in eslintrc for tests. The env has been updated from mocha to jest.

* Adding eslint-plugin-jest and further modify tests.

- One small fix in sqllab's Timer Spec for a test that is not using the spy it created for testing.
- Deletion of a duplicated test caught by eslint-plugin-jest.

* - Make istanbul coverage work with Jest.

- Remove dependency on stand-alone istanbul and babel-istanbul as they're built-into jest. Yes!

* Attempt to fix dynamic imports in tests.

* run sequentially and log heap usage

* - tweaking maxworkers for travis and specifying coverageDirectory for codecov

- remove dynamic import in shim.js now that it is set in babelrc for tests only.

superset/assets/spec/javascripts/utils/common_spec.jsx

@@ -1,52 +1,51 @@
-import { expect } from 'chai';
 import { isTruthy, optionFromValue } from '../../../src/utils/common';
 
 describe('utils/common', () => {
   describe('isTruthy', () => {
     it('evals false-looking strings properly', () => {
-      expect(isTruthy('f')).to.equal(false);
-      expect(isTruthy('false')).to.equal(false);
-      expect(isTruthy('no')).to.equal(false);
-      expect(isTruthy('n')).to.equal(false);
-      expect(isTruthy('F')).to.equal(false);
-      expect(isTruthy('False')).to.equal(false);
-      expect(isTruthy('NO')).to.equal(false);
-      expect(isTruthy('N')).to.equal(false);
+      expect(isTruthy('f')).toBe(false);
+      expect(isTruthy('false')).toBe(false);
+      expect(isTruthy('no')).toBe(false);
+      expect(isTruthy('n')).toBe(false);
+      expect(isTruthy('F')).toBe(false);
+      expect(isTruthy('False')).toBe(false);
+      expect(isTruthy('NO')).toBe(false);
+      expect(isTruthy('N')).toBe(false);
     });
     it('evals true-looking strings properly', () => {
-      expect(isTruthy('t')).to.equal(true);
-      expect(isTruthy('true')).to.equal(true);
-      expect(isTruthy('yes')).to.equal(true);
-      expect(isTruthy('y')).to.equal(true);
-      expect(isTruthy('Y')).to.equal(true);
-      expect(isTruthy('True')).to.equal(true);
-      expect(isTruthy('Yes')).to.equal(true);
-      expect(isTruthy('YES')).to.equal(true);
+      expect(isTruthy('t')).toBe(true);
+      expect(isTruthy('true')).toBe(true);
+      expect(isTruthy('yes')).toBe(true);
+      expect(isTruthy('y')).toBe(true);
+      expect(isTruthy('Y')).toBe(true);
+      expect(isTruthy('True')).toBe(true);
+      expect(isTruthy('Yes')).toBe(true);
+      expect(isTruthy('YES')).toBe(true);
     });
     it('evals bools properly', () => {
-      expect(isTruthy(false)).to.equal(false);
-      expect(isTruthy(true)).to.equal(true);
+      expect(isTruthy(false)).toBe(false);
+      expect(isTruthy(true)).toBe(true);
     });
     it('evals ints properly', () => {
-      expect(isTruthy(0)).to.equal(false);
-      expect(isTruthy(1)).to.equal(true);
+      expect(isTruthy(0)).toBe(false);
+      expect(isTruthy(1)).toBe(true);
     });
     it('evals constants properly', () => {
-      expect(isTruthy(null)).to.equal(false);
-      expect(isTruthy(undefined)).to.equal(false);
+      expect(isTruthy(null)).toBe(false);
+      expect(isTruthy(undefined)).toBe(false);
     });
     it('string auto is false', () => {
-      expect(isTruthy('false')).to.equal(false);
+      expect(isTruthy('false')).toBe(false);
     });
   });
   describe('optionFromValue', () => {
     it('converts values as expected', () => {
-      expect(optionFromValue(false)).to.deep.equal({ value: false, label: '<false>' });
-      expect(optionFromValue(true)).to.deep.equal({ value: true, label: '<true>' });
-      expect(optionFromValue(null)).to.deep.equal({ value: '<NULL>', label: '<NULL>' });
-      expect(optionFromValue('')).to.deep.equal({ value: '', label: '<empty string>' });
-      expect(optionFromValue('foo')).to.deep.equal({ value: 'foo', label: 'foo' });
-      expect(optionFromValue(5)).to.deep.equal({ value: 5, label: '5' });
+      expect(optionFromValue(false)).toEqual({ value: false, label: '<false>' });
+      expect(optionFromValue(true)).toEqual({ value: true, label: '<true>' });
+      expect(optionFromValue(null)).toEqual({ value: '<NULL>', label: '<NULL>' });
+      expect(optionFromValue('')).toEqual({ value: '', label: '<empty string>' });
+      expect(optionFromValue('foo')).toEqual({ value: 'foo', label: 'foo' });
+      expect(optionFromValue(5)).toEqual({ value: 5, label: '5' });
     });
   });
 });

superset/assets/spec/javascripts/utils/convertKeysToCamelCase_spec.js

@@ -1,13 +1,11 @@
-import { it, describe } from 'mocha';
-import { expect } from 'chai';
 import convertKeysToCamelCase from '../../../src/utils/convertKeysToCamelCase';
 
 describe('convertKeysToCamelCase(object)', () => {
   it('returns undefined for undefined input', () => {
-    expect(convertKeysToCamelCase(undefined)).to.equal(undefined);
+    expect(convertKeysToCamelCase(undefined)).toBeUndefined();
   });
   it('returns null for null input', () => {
-    expect(convertKeysToCamelCase(null)).to.equal(null);
+    expect(convertKeysToCamelCase(null)).toBeNull();
   });
   it('returns a new object that has all keys in camelCase', () => {
     const input = {
@@ -15,15 +13,15 @@ describe('convertKeysToCamelCase(object)', () => {
       'is-angry': false,
       isHungry: false,
     };
-    expect(convertKeysToCamelCase(input)).to.deep.equal({
+    expect(convertKeysToCamelCase(input)).toEqual({
       isHappy: true,
       isAngry: false,
       isHungry: false,
     });
   });
   it('throws error if input is not a plain object', () => {
-    expect(() => { convertKeysToCamelCase({}); }).to.not.throw();
-    expect(() => { convertKeysToCamelCase(''); }).to.throw();
-    expect(() => { convertKeysToCamelCase(new Map()); }).to.throw();
+    expect(() => { convertKeysToCamelCase({}); }).not.toThrowError();
+    expect(() => { convertKeysToCamelCase(''); }).toThrowError();
+    expect(() => { convertKeysToCamelCase(new Map()); }).toThrowError();
   });
 });

superset/assets/spec/javascripts/utils/isDefined_spec.js

@@ -1,22 +1,20 @@
-import { it, describe } from 'mocha';
-import { expect } from 'chai';
 import isDefined from '../../../src/utils/isDefined';
 
 describe('isDefined(value)', () => {
   it('returns true if value is not null and not undefined', () => {
-    expect(isDefined(0)).to.equal(true);
-    expect(isDefined(1)).to.equal(true);
-    expect(isDefined('')).to.equal(true);
-    expect(isDefined('a')).to.equal(true);
-    expect(isDefined([])).to.equal(true);
-    expect(isDefined([0])).to.equal(true);
-    expect(isDefined([1])).to.equal(true);
-    expect(isDefined({})).to.equal(true);
-    expect(isDefined({ a: 1 })).to.equal(true);
-    expect(isDefined([{}])).to.equal(true);
+    expect(isDefined(0)).toBe(true);
+    expect(isDefined(1)).toBe(true);
+    expect(isDefined('')).toBe(true);
+    expect(isDefined('a')).toBe(true);
+    expect(isDefined([])).toBe(true);
+    expect(isDefined([0])).toBe(true);
+    expect(isDefined([1])).toBe(true);
+    expect(isDefined({})).toBe(true);
+    expect(isDefined({ a: 1 })).toBe(true);
+    expect(isDefined([{}])).toBe(true);
   });
   it('returns false otherwise', () => {
-    expect(isDefined(null)).to.equal(false);
-    expect(isDefined(undefined)).to.equal(false);
+    expect(isDefined(null)).toBe(false);
+    expect(isDefined(undefined)).toBe(false);
   });
 });

superset/assets/spec/javascripts/utils/isRequired_spec.js

@@ -1,9 +1,7 @@
-import { it, describe } from 'mocha';
-import { expect } from 'chai';
 import isRequired from '../../../src/utils/isRequired';
 
 describe('isRequired(field)', () => {
   it('should throw error with the given field in the message', () => {
-    expect(() => isRequired('myField')).to.throw(Error, 'myField is required.');
+    expect(() => isRequired('myField')).toThrowError(Error);
   });
 });

superset/assets/spec/javascripts/utils/makeSingleton_spec.js

@@ -1,5 +1,3 @@
-import { describe, it } from 'mocha';
-import { expect } from 'chai';
 import makeSingleton from '../../../src/utils/makeSingleton';
 
 describe('makeSingleton()', () => {
@@ -14,24 +12,30 @@ describe('makeSingleton()', () => {
   describe('makeSingleton(BaseClass)', () => {
     const getInstance = makeSingleton(Dog);
 
-    it('returns a function for getting singleton instance of a given base class', () => {
-      expect(getInstance).to.be.a('Function');
-      expect(getInstance()).to.be.instanceOf(Dog);
-    });
+    it(
+      'returns a function for getting singleton instance of a given base class',
+      () => {
+        expect(typeof getInstance).toBe('function');
+        expect(getInstance()).toBeInstanceOf(Dog);
+      },
+    );
     it('returned function returns same instance across all calls', () => {
-      expect(getInstance()).to.equal(getInstance());
+      expect(getInstance()).toBe(getInstance());
     });
   });
   describe('makeSingleton(BaseClass, ...args)', () => {
     const getInstance = makeSingleton(Dog, 'Doug');
 
-    it('returns a function for getting singleton instance of a given base class constructed with the given arguments', () => {
-      expect(getInstance).to.be.a('Function');
-      expect(getInstance()).to.be.instanceOf(Dog);
-      expect(getInstance().name).to.equal('Doug');
-    });
+    it(
+      'returns a function for getting singleton instance of a given base class constructed with the given arguments',
+      () => {
+        expect(typeof getInstance).toBe('function');
+        expect(getInstance()).toBeInstanceOf(Dog);
+        expect(getInstance().name).toBe('Doug');
+      },
+    );
     it('returned function returns same instance across all calls', () => {
-      expect(getInstance()).to.equal(getInstance());
+      expect(getInstance()).toBe(getInstance());
     });
   });