refactor: consolidate check-email into Elysia rate limiter (Task 6)

lib/api/__tests__/check-email.test.ts

@@ -0,0 +1,41 @@
+import { describe, it, expect } from "vitest"
+import { loginEmailSchema } from "@/lib/auth/validation"
+
+describe("check-email validation", () => {
+  it("accepts valid email", () => {
+    const result = loginEmailSchema.safeParse({ email: "user@example.com" })
+    expect(result.success).toBe(true)
+  })
+
+  it("rejects missing email", () => {
+    const result = loginEmailSchema.safeParse({})
+    expect(result.success).toBe(false)
+  })
+
+  it("rejects invalid email format", () => {
+    const result = loginEmailSchema.safeParse({ email: "not-email" })
+    expect(result.success).toBe(false)
+  })
+
+  it("rejects empty string email", () => {
+    const result = loginEmailSchema.safeParse({ email: "" })
+    expect(result.success).toBe(false)
+  })
+})
+
+describe("check-email response contract", () => {
+  it("returns { exists: boolean } on success", () => {
+    const successShape = { exists: true }
+    const failureShape = { exists: false }
+    expect(successShape).toHaveProperty("exists")
+    expect(failureShape).toHaveProperty("exists")
+    expect(typeof successShape.exists).toBe("boolean")
+    expect(typeof failureShape.exists).toBe("boolean")
+  })
+
+  it("returns { error: string } on validation failure", () => {
+    const errorShape = { error: "Invalid request body" }
+    expect(errorShape).toHaveProperty("error")
+    expect(typeof errorShape.error).toBe("string")
+  })
+})