Combine all sources into a sub-directory

sources/jest.config.js

@@ -0,0 +1,10 @@
+module.exports = {
+  clearMocks: true,
+  moduleFileExtensions: ['js', 'ts', 'json'],
+  testEnvironment: 'node',
+  testMatch: ['**/*.test.ts'],
+  transform: {
+    '^.+\\.ts$': 'ts-jest'
+  },
+  verbose: true
+}