assertTrue(str.contains("CLOSED"));
        assertTrue(str.contains("100.00%"));
    }

    @Test
    @DisplayName("Test mixed success and failure pattern")
    void testMixedPattern() throws Exception {
        // Success
        circuitBreaker.call(() -> "success");

        // Two failures (not enough to open)
        for (int i = 0; i < 2; i++) {
            try {