Replace test framework: jest -> vitest (#281)

* Replace test framework: jest -> vitest

* nit - remove deprecated npm scripts

* Add vitest config

* Add a few basic tests

* Update actions with vitest params

* Add correct expectations

* Remove jest config

test/lgTest.ts

@@ -0,0 +1,56 @@
+import { test } from "vitest"
+import type { ISerialisedGraph } from "../src/types/serialisation"
+import { LGraph } from "@/LGraph"
+
+const minimalSerialisableGraph: ISerialisedGraph = {
+  version: 1,
+  config: {},
+  last_node_id: 0,
+  last_link_id: 0,
+  nodes: [],
+  links: [],
+  groups: [],
+}
+
+const basicSerialisableGraph: ISerialisedGraph = {
+  version: 1,
+  config: {},
+  last_node_id: 0,
+  last_link_id: 0,
+  groups: [
+    {
+      id: 123,
+      bounding: [20, 20, 1, 3],
+      color: "#6029aa",
+      font_size: 14,
+      title: "A group to test with",
+    },
+  ],
+  nodes: [
+    {
+      id: 1,
+    },
+  ],
+  links: [],
+}
+
+interface LitegraphFixtures {
+  minimalGraph: LGraph
+  minimalSerialisableGraph: ISerialisedGraph
+  basicSerialisableGraph: ISerialisedGraph
+}
+
+export const lgTest = test.extend<LitegraphFixtures>({
+  minimalGraph: async ({}, use) => {
+    // Before each test function
+    const serialisable = structuredClone(minimalSerialisableGraph)
+    const lGraph = new LGraph(serialisable)
+
+    // use the fixture value
+    await use(lGraph)
+
+    // After each test function
+  },
+  basicSerialisableGraph: structuredClone(basicSerialisableGraph),
+  minimalSerialisableGraph: structuredClone(minimalSerialisableGraph),
+})