test: add device token validation and text utility tests

internal/handlers/devices_test.go

@@ -200,3 +200,24 @@ func TestDeviceUpdateRequest_Validation(t *testing.T) {
 		})
 	}
 }
+
+func TestValidateDeviceToken(t *testing.T) {
+	hashedToken := []byte("$2a$10$92IXUNpkjO0rOQ5byMi.Ye4oKoEa3Ro9llC/.og/at2.uheWG/igi")
+	plainToken := "password"
+
+	result := ValidateDeviceToken(string(hashedToken), plainToken)
+	assert.True(t, result, "Valid token should return true")
+}
+
+func TestValidateDeviceToken_Invalid(t *testing.T) {
+	hashedToken := []byte("$2a$10$92IXUNpkjO0rOQ5byMi.Ye4oKoEa3Ro9llC/.og/at2.uheWG/igi")
+	plainToken := "wrongpassword"
+
+	result := ValidateDeviceToken(string(hashedToken), plainToken)
+	assert.False(t, result, "Invalid token should return false")
+}
+
+func TestValidateDeviceToken_Empty(t *testing.T) {
+	result := ValidateDeviceToken("", "anypassword")
+	assert.False(t, result, "Empty hash should return false")
+}