assertEquals(0, stats.totalFailures);
        assertEquals(1.0, stats.successRate);
    }

    @Test
    @DisplayName("Test circuit opens after failure threshold")
    void testCircuitOpensAfterThreshold() {
        // Fail 3 times to open the circuit
        for (int i = 0; i < 3; i++) {
            try {
                circuitBreaker.call(() -> {
                    throw new RuntimeException("Test failure");