test: setup stryker mutation testing

[ChristianMurphy]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)
• If applicable, I’ve added docs and tests

Description of changes

Adds Stryker as a mutation testing tool, which tests the tests, by making breaking changes in the source code, and see if the tests still pass.

[ChristianMurphy]

initial results

All tests
  ✓ All tests (killed 306)

#10. [Survived] BooleanLiteral
lib/index.js:84:29
-       destination.data(extend(true, {}, namespace))
+       destination.data(extend(false, {}, namespace))
Ran all tests for this mutant.

#31. [Survived] StringLiteral
lib/index.js:109:22
-         assertUnfrozen('data', frozen)
+         assertUnfrozen("", frozen)
Ran all tests for this mutant.

#34. [Survived] ConditionalExpression
lib/index.js:120:9
-       if (frozen) {
+       if (false) {
Ran all tests for this mutant.

#35. [Survived] BlockStatement
lib/index.js:120:17
-       if (frozen) {
-         return processor
-       }
+       if (frozen) {}
Ran all tests for this mutant.

#46. [Survived] ConditionalExpression
lib/index.js:131:11
-         if (options[0] === true) {
+         if (true) {
Ran all tests for this mutant.

#47. [Survived] ConditionalExpression
lib/index.js:131:11
-         if (options[0] === true) {
+         if (false) {
Ran all tests for this mutant.

#48. [Survived] EqualityOperator
lib/index.js:131:11
-         if (options[0] === true) {
+         if (options[0] !== true) {
Ran all tests for this mutant.

#49. [Survived] BooleanLiteral
lib/index.js:131:26
-         if (options[0] === true) {
+         if (options[0] === false) {
Ran all tests for this mutant.

#50. [Survived] BlockStatement
lib/index.js:131:32
-         if (options[0] === true) {
-           options[1] = undefined
-         }
+         if (options[0] === true) {}
Ran all tests for this mutant.

#85. [Survived] ConditionalExpression
lib/index.js:174:9
-       if (settings) {
+       if (true) {
Ran all tests for this mutant.

#110. [Survived] ConditionalExpression
lib/index.js:206:11
-         if (result.settings) {
+         if (true) {
Ran all tests for this mutant.

#113. [Survived] ConditionalExpression
lib/index.js:207:34
-           settings = Object.assign(settings || {}, result.settings)
+           settings = Object.assign(true, result.settings)
Ran all tests for this mutant.

#114. [Survived] ConditionalExpression
lib/index.js:207:34
-           settings = Object.assign(settings || {}, result.settings)
+           settings = Object.assign(false, result.settings)
Ran all tests for this mutant.

#122. [Survived] ConditionalExpression
lib/index.js:218:11
-         if (plugins === null || plugins === undefined) {
+         if (false || plugins === undefined) {
Ran all tests for this mutant.

#156. [Survived] BooleanLiteral
lib/index.js:249:26
-             value = extend(true, entry[1], value)
+             value = extend(false, entry[1], value)
Ran all tests for this mutant.

#213. [Survived] LogicalOperator
lib/index.js:394:13
-           if (error || !tree || !file) {
+           if ((error || !tree) && !file) {
Ran all tests for this mutant.

#215. [Survived] ConditionalExpression
lib/index.js:394:13
-           if (error || !tree || !file) {
+           if (false || !file) {
Ran all tests for this mutant.

#216. [Survived] LogicalOperator
lib/index.js:394:13
-           if (error || !tree || !file) {
+           if (error && !tree || !file) {
Ran all tests for this mutant.

#223. [Survived] LogicalOperator
lib/index.js:400:15
-             if (result === undefined || result === null) {
+             if (result === undefined && result === null) {
Ran all tests for this mutant.

#222. [Survived] ConditionalExpression
lib/index.js:400:15
-             if (result === undefined || result === null) {
+             if (false) {
Ran all tests for this mutant.

#225. [Survived] ConditionalExpression
lib/index.js:400:15
-             if (result === undefined || result === null) {
+             if (false || result === null) {
Ran all tests for this mutant.

#228. [Survived] ConditionalExpression
lib/index.js:400:39
-             if (result === undefined || result === null) {
+             if (result === undefined || false) {
Ran all tests for this mutant.

#237. [Survived] LogicalOperator
lib/index.js:418:13
-           if (error || !file) {
+           if (error && !file) {
Ran all tests for this mutant.

#247. [Survived] StringLiteral
lib/index.js:443:16
-       assertDone('processSync', 'process', complete)
+       assertDone("", 'process', complete)
Ran all tests for this mutant.

#248. [Survived] StringLiteral
lib/index.js:443:31
-       assertDone('processSync', 'process', complete)
+       assertDone('processSync', "", complete)
Ran all tests for this mutant.

#258. [Survived] ConditionalExpression
lib/index.js:467:5
-       typeof value === 'function' &&
+       true &&
Ran all tests for this mutant.

#266. [Survived] BlockStatement
lib/index.js:489:22
-     for (key in value) {
-       if (own.call(value, key)) {
-         return true
-       }
-     }
+     for (key in value) {}
Ran all tests for this mutant.

#265. [Survived] BlockStatement
lib/index.js:485:22
-   function keys(value) {
-     /** @type {string} */
-     let key
-     for (key in value) {
-       if (own.call(value, key)) {
-         return true
-       }
-     }
-     return false
-   }
+   function keys(value) {}
Ran all tests for this mutant.

#267. [Survived] ConditionalExpression
lib/index.js:490:9
-       if (own.call(value, key)) {
+       if (true) {
Ran all tests for this mutant.

#268. [Survived] ConditionalExpression
lib/index.js:490:9
-       if (own.call(value, key)) {
+       if (false) {
Ran all tests for this mutant.

#269. [Survived] BlockStatement
lib/index.js:490:31
-       if (own.call(value, key)) {
-         return true
-       }
+       if (own.call(value, key)) {}
Ran all tests for this mutant.

#270. [Survived] BooleanLiteral
lib/index.js:491:14
-         return true
+         return false
Ran all tests for this mutant.

#300. [Survived] ConditionalExpression
lib/index.js:550:28
-     if (!isPlainObj(node) || typeof node.type !== 'string') {
+     if (!isPlainObj(node) || false) {
Ran all tests for this mutant.

Ran 1.00 tests per mutant on average.
----------|---------|----------|-----------|------------|----------|---------|
File      | % score | # killed | # timeout | # survived | # no cov | # error |
----------|---------|----------|-----------|------------|----------|---------|
All files |   90.27 |      306 |         0 |         33 |        0 |       0 |
 index.js |   90.27 |      306 |         0 |         33 |        0 |       0 |
----------|---------|----------|-----------|------------|----------|---------|
07:44:19 (344898) ERROR MutationTestReportHelper Final mutation score 90.27 under breaking threshold 100, setting exit code to 1 (failure).