add: unit and integration testing

app/node_modules/@istanbuljs/schema/default-exclude.js

@@ -0,0 +1,22 @@
+'use strict';
+
+const defaultExtension = require('./default-extension.js');
+const testFileExtensions = defaultExtension
+	.map(extension => extension.slice(1))
+	.join(',');
+
+module.exports = [
+	'coverage/**',
+	'packages/*/test{,s}/**',
+	'**/*.d.ts',
+	'test{,s}/**',
+	`test{,-*}.{${testFileExtensions}}`,
+	`**/*{.,-}test.{${testFileExtensions}}`,
+	'**/__tests__/**',
+
+	/* Exclude common development tool configuration files */
+	'**/{ava,babel,nyc}.config.{js,cjs,mjs}',
+	'**/jest.config.{js,cjs,mjs,ts}',
+	'**/{karma,rollup,webpack}.config.js',
+	'**/.{eslint,mocha}rc.{js,cjs}'
+];