Add unit testing support with vitest (#18)

* update loose files and add vitest

* update test scripts

* more support for vitest

* more test support

* update vscode settings

.gitignore

@@ -15,6 +15,7 @@ dist-ssr
 # Editor directories and files
 .vscode/*
 !.vscode/extensions.json
+!.vscode/settings.json
 .idea
 .DS_Store
 *.suo
@@ -32,3 +33,5 @@ public/images/pokemon/icons/input/output/*
 public/images/character/*/
 src/data/battle-anim-raw-data*.ts
 src/data/battle-anim-data.ts
+
+coverage