userfront&backend test coverage 추가

backend/internal/utils/password_policy_test.go

@@ -22,6 +22,11 @@ func TestValidatePasswordWithPolicy(t *testing.T) {
 		assert.NoError(t, err)
 	})
 
+	t.Run("Nil Policy", func(t *testing.T) {
+		err := ValidatePasswordWithPolicy(nil, "")
+		assert.NoError(t, err)
+	})
+
 	t.Run("Too Short", func(t *testing.T) {
 		err := ValidatePasswordWithPolicy(policy, "P123!")
 		assert.Error(t, err)
@@ -34,11 +39,29 @@ func TestValidatePasswordWithPolicy(t *testing.T) {
 		assert.Contains(t, err.Error(), "소문자")
 	})
 
+	t.Run("Missing Uppercase", func(t *testing.T) {
+		err := ValidatePasswordWithPolicy(policy, "pass1234!")
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "대문자")
+	})
+
+	t.Run("Missing Number", func(t *testing.T) {
+		err := ValidatePasswordWithPolicy(policy, "Password!")
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "숫자")
+	})
+
 	t.Run("Missing Symbol", func(t *testing.T) {
 		err := ValidatePasswordWithPolicy(policy, "Pass1234")
 		assert.Error(t, err)
 		assert.Contains(t, err.Error(), "특수문자")
 	})
+
+	t.Run("Missing Minimum Character Types", func(t *testing.T) {
+		err := ValidatePasswordWithPolicy(&domain.PasswordPolicy{MinLength: 4, MinCharacterTypes: 4}, "abcd")
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "4가지")
+	})
 }
 
 func TestGeneratePasswordWithPolicy(t *testing.T) {
@@ -55,8 +78,51 @@ func TestGeneratePasswordWithPolicy(t *testing.T) {
 		assert.NoError(t, err)
 		assert.Len(t, password, 16)
 
-		// Generated password must satisfy the policy
 		err = ValidatePasswordWithPolicy(policy, password)
 		assert.NoError(t, err, "Generated password '%s' does not satisfy policy", password)
 	})
+
+	t.Run("Nil Policy Uses Default Length", func(t *testing.T) {
+		password, err := GeneratePasswordWithPolicy(nil)
+		assert.NoError(t, err)
+		assert.Len(t, password, 12)
+	})
+
+	t.Run("Minimum Character Types Adds Optional Categories", func(t *testing.T) {
+		policy := &domain.PasswordPolicy{
+			MinLength:         4,
+			Lowercase:         true,
+			MinCharacterTypes: 4,
+		}
+
+		password, err := GeneratePasswordWithPolicy(policy)
+		assert.NoError(t, err)
+		assert.Len(t, password, 4)
+		assert.NoError(t, ValidatePasswordWithPolicy(policy, password))
+	})
+
+	t.Run("Required Categories Raise Short Minimum Length", func(t *testing.T) {
+		policy := &domain.PasswordPolicy{
+			MinLength:       1,
+			Lowercase:       true,
+			Uppercase:       true,
+			Number:          true,
+			NonAlphanumeric: true,
+		}
+
+		password, err := GeneratePasswordWithPolicy(policy)
+		assert.NoError(t, err)
+		assert.Len(t, password, 4)
+		assert.NoError(t, ValidatePasswordWithPolicy(policy, password))
+	})
+}
+
+func TestPasswordPolicyRandomHelpersRejectInvalidInput(t *testing.T) {
+	_, err := randomIndex(0)
+	assert.Error(t, err)
+
+	_, err = randomChar("")
+	assert.Error(t, err)
+
+	assert.NoError(t, shuffleRunes([]rune("a")))
 }