feat: reject token if it's not valid

src/libs/changeStringCase.spec.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it } from "bun:test";
+
+import { Case, changeStringCase } from "./changeStringCase";
+
+describe("changeStringCase", () => {
+  it("from camelCase to snake_case", () => {
+    expect(
+      changeStringCase("camelCase", Case.camelCase, Case.snake_case),
+    ).toEqual("camel_case");
+  });
+
+  it("from snake_case to camelCase", () => {
+    expect(
+      changeStringCase("snake_case", Case.snake_case, Case.camelCase),
+    ).toEqual("snakeCase");
+  });
+
+  it("from camelCase to camelCase", () => {
+    expect(
+      changeStringCase("camelCase", Case.camelCase, Case.camelCase),
+    ).toEqual("camelCase");
+  });
+
+  it("from snake_case to snake_case", () => {
+    expect(
+      changeStringCase("snake_case", Case.snake_case, Case.snake_case),
+    ).toEqual("snake_case");
+  });
+});