test: add support for doing snapshot testing

Snapshot testing is one of the idiomatic way of producing
tests while building a parser.

Our snapshot tests will be of two types
a.) Dehydrated ApiDOM snapshot testing

Best for keeping track of data and metadata encoded
within ApiDOM.

b.) S-expresssion representation of ApiDOM

Best for checking if semantics of ApiDOM Tree
are correct.

Closes #432

apidom/package.json

@@ -77,7 +77,8 @@
     "link-parent-bin": "=1.0.2",
     "lint-staged": "=10.2.7",
     "microtime": "=3.0.0",
-    "mocha": "=7.2.0",
+    "mocha": "=8.4.0",
+    "mocha-chai-jest-snapshot": "=1.1.2",
     "node-gyp": "=7.1.2",
     "npm-run-all": "=4.1.5",
     "prettier": "=2.0.5",

apidom/packages/apidom-ns-asyncapi-2-0/.mocharc.js

@@ -3,5 +3,5 @@
 module.exports = {
   recursive: true,
   spec: 'test/**/*.ts',
-  require: ['test/mocha-bootstrap.js'],
+  file: ['test/mocha-bootstrap.js'],
 };

apidom/packages/apidom-ns-asyncapi-2-0/package.json

@@ -16,6 +16,7 @@
     "lint:fix": "eslint ./ --fix",
     "clean": "rimraf ./es ./cjs ./dist ./types",
     "test": "cross-env BABEL_ENV=cjs mocha",
+    "test:update-snapshots": "cross-env UPDATE_SNAPSHOT=1 BABEL_ENV=cjs mocha",
     "perf": "cross-env BABEL_ENV=cjs node ./test/perf/index.js",
     "perf:visitor-shortcut": "cross-env BABEL_ENV=cjs node ./test/perf/visitor-shortcut.js",
     "typescript:check-types": "tsc --noEmit",

apidom/packages/apidom-ns-asyncapi-2-0/test/mocha-bootstrap.js

@@ -1 +1,11 @@
 require('@babel/register')({ extensions: ['.js', '.ts'], rootMode: 'upward' });
+
+const chai = require('chai');
+const { jestSnapshotPlugin, addSerializer } = require('mocha-chai-jest-snapshot');
+
+const jestApiDOMSerializer = require('../../../scripts/jest-serializer-apidom');
+const jestStringSerializer = require('../../../scripts/jest-serializer-string');
+
+chai.use(jestSnapshotPlugin());
+addSerializer(jestApiDOMSerializer);
+addSerializer(jestStringSerializer);

apidom/packages/apidom-ns-asyncapi-2-0/test/refractor/__snapshots__/index.ts.snap

@@ -0,0 +1,40 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`refractor given generic ApiDOM object in AsyncApi 2.0 shape should refract to AsyncApi 2.0 Element 1`] = `
+{
+  "element": "asyncApi2_0",
+  "meta": {
+    "classes": {
+      "element": "array",
+      "content": [
+        {
+          "element": "string",
+          "content": "api"
+        }
+      ]
+    }
+  },
+  "content": [
+    {
+      "element": "member",
+      "content": {
+        "key": {
+          "element": "string",
+          "content": "asyncapi"
+        },
+        "value": {
+          "element": "asyncApiVersion",
+          "content": "2.0.0"
+        }
+      }
+    }
+  ]
+}
+`;
+
+exports[`refractor given generic ApiDOM object in AsyncApi 2.0 shape should refract to semantic ApiDOM tree 1`] = `
+(AsyncApi2_0Element
+  (MemberElement
+    (StringElement)
+    (AsyncApiVersionElement)))
+`;

apidom/packages/apidom-ns-asyncapi-2-0/test/refractor/index.ts

@@ -1,20 +1,25 @@
-import { assert } from 'chai';
+import { assert, expect } from 'chai';
 import sinon from 'sinon';
 import { Namespace } from 'minim';
-import { ObjectElement, toValue } from 'apidom';
+import { ObjectElement, toValue, sexprs } from 'apidom';
 
 import * as predicates from '../../src/predicates';
 import { AsyncApi2_0Element, AsyncApiVersionElement, isAsyncApiVersionElement } from '../../src';
 
 describe('refractor', function () {
-  specify('should refract to AsyncApi 2.0 namespace', function () {
+  context('given generic ApiDOM object in AsyncApi 2.0 shape', function () {
     const genericObject = new ObjectElement({
       asyncapi: '2.0.0',
     });
     const asyncApiElement = AsyncApi2_0Element.refract(genericObject);
 
-    // console.log(toString(asyncApiElement));
-    assert.deepEqual(toValue(asyncApiElement), { asyncapi: '2.0.0' });
+    specify('should refract to semantic ApiDOM tree', function () {
+      expect(sexprs(asyncApiElement)).toMatchSnapshot();
+    });
+
+    specify('should refract to AsyncApi 2.0 Element', function () {
+      expect(asyncApiElement).toMatchSnapshot();
+    });
   });
 
   context('supports plugins', function () {

apidom/scripts/jest-serializer-apidom.js

@@ -0,0 +1,6 @@
+const { isElement, dehydrate } = require('../packages/apidom');
+
+module.exports = {
+  test: isElement,
+  print: (val) => JSON.stringify(dehydrate(val), null, 2),
+};

apidom/scripts/jest-serializer-string.js

@@ -0,0 +1,7 @@
+const { identity } = require('ramda');
+const { isString } = require('ramda-adjunct');
+
+module.exports = {
+  test: isString,
+  print: identity,
+};