From 34e66de8b35d89616daaef3edd888b2667829c38 Mon Sep 17 00:00:00 2001
From: Adrian Bonpin <adrianbonpin@gmail.com>
Date: Wed, 27 May 2026 02:42:34 +0800
Subject: [PATCH] test: add password strength tests (Task 2)

---
 lib/auth/__tests__/password-strength.test.ts | 63 ++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 lib/auth/__tests__/password-strength.test.ts

diff --git a/lib/auth/__tests__/password-strength.test.ts b/lib/auth/__tests__/password-strength.test.ts
new file mode 100644
index 0000000..edb20cd
--- /dev/null
+++ b/lib/auth/__tests__/password-strength.test.ts
@@ -0,0 +1,63 @@
+import { describe, it, expect } from "vitest"
+import { checkPasswordStrength } from "../password-strength"
+
+describe("checkPasswordStrength", () => {
+  it("returns weak (score 0) for empty string", () => {
+    const result = checkPasswordStrength("")
+    expect(result.level).toBe("weak")
+    expect(result.score).toBe(0)
+    expect(result.feedback).toContain("Enter a password")
+  })
+
+  it("returns fair for 'password' (common pattern penalty)", () => {
+    const result = checkPasswordStrength("password")
+    expect(result.level).toBe("fair")
+    expect(result.feedback).toContain("Avoid common passwords")
+  })
+
+  it("returns fair for short password with only letters", () => {
+    const result = checkPasswordStrength("abc")
+    expect(result.level).toBe("fair")
+  })
+
+  it("returns good for 10-char lowercase-only password", () => {
+    const result = checkPasswordStrength("abcdefghij")
+    expect(result.level).toBe("good")
+  })
+
+  it("returns good for 10-char mixed case + numbers", () => {
+    const result = checkPasswordStrength("AbcDef1234")
+    expect(["good", "strong", "excellent"]).toContain(result.level)
+  })
+
+  it("returns strong for 14-char with all character types", () => {
+    const result = checkPasswordStrength("MyP@ssw0rd!2024")
+    expect(["strong", "excellent"]).toContain(result.level)
+  })
+
+  it("returns excellent for 18+ char complex password", () => {
+    const result = checkPasswordStrength("C0mpl3x!P@ssw0rd#2024")
+    expect(result.level).toBe("excellent")
+  })
+
+  it("flags repeated characters", () => {
+    const result = checkPasswordStrength("aaaBBB111@@@")
+    expect(result.feedback).toContain("Avoid repeated characters")
+  })
+
+  it("flags common patterns like 'letmein'", () => {
+    const result = checkPasswordStrength("letmein1234")
+    expect(result.feedback).toContain("Avoid common passwords")
+  })
+
+  it("gives positive feedback for excellent passwords", () => {
+    const result = checkPasswordStrength("Tr0ub4dor&3X7r3m3ly!")
+    expect(result.feedback).toContain("Great password!")
+  })
+
+  it("handles unicode characters", () => {
+    const result = checkPasswordStrength("パスワード1234Abc!")
+    expect(result.level).toBeDefined()
+    expect(result.score).toBeGreaterThan(0)
+  })
+})
\ No newline at end of file