jest: set up for coverage

Author: baob

.prettierignore

@@ -0,0 +1,4 @@
+node_modules
+yarn.lock
+*.snap
+coverage/*

jest.config.js

@@ -7,4 +7,14 @@ module.exports = {
     name: pack.name,
     testEnvironment: 'node',
     coveragePathIgnorePatterns: ['/node_modules/'],
+    coverageThreshold: {
+        global: {
+            statements: 0,
+            branches: 0,
+            functions: 0,
+            lines: 0,
+        },
+    },
+    coverageReporters: ['lcov', 'text-summary'],
+    collectCoverageFrom: ['**/*.js'],
 };