Add test coverage script (#929)

## Description:

Added a command "npm run test:coverage"
This could be added to the CI/CD to check if a pull request induced
regressions, and if it added propers tests.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

## Please put your Discord username so you can be contacted if a bug or
regression is found:

theodoreleon.aetarax

.gitignore

@@ -2,6 +2,7 @@ build/
 node_modules/
 out/
 static/
+coverage/
 TODO.txt
 resources/images/.DS_Store
 resources/.DS_Store

jest.config.ts

@@ -17,4 +17,14 @@ export default {
   },
   transformIgnorePatterns: ["node_modules/(?!(node:)/)"],
   preset: "ts-jest/presets/default-esm",
+  collectCoverageFrom: ["src/**/*.ts", "!src/**/*.d.ts"],
+  coverageThreshold: {
+    global: {
+      branches: 0,
+      functions: 0,
+      lines: 0,
+      statements: 0,
+    },
+  },
+  coverageReporters: ["text", "lcov", "html"],
 };

package.json

@@ -10,6 +10,7 @@
     "dev": "cross-env GAME_ENV=dev concurrently \"npm run start:client\" \"npm run start:server-dev\"",
     "tunnel": "npm run build-prod && npm run start:server",
     "test": "jest",
+    "test:coverage": "jest --coverage",
     "format": "prettier --ignore-unknown --write .",
     "lint": "eslint",
     "lint:fix": "eslint --fix",