Nextus-Web/src/test/java/dev/coph/nextusweb/server/ratelimit/TokenBucketLimiterTest.java

package dev.coph.nextusweb.server.ratelimit;

import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.*;

class TokenBucketLimiterTest {

    @Test
    void burstUpToCapacityIsAllowed() {
        TokenBucketLimiter lim = new TokenBucketLimiter(1, 3);
        long now = 0;
        assertTrue(lim.tryAcquire("k", now).allowed());
        assertTrue(lim.tryAcquire("k", now).allowed());
        assertTrue(lim.tryAcquire("k", now).allowed());
    }

    @Test
    void emptyBucketIsDeniedAndRetryAfterIsPositive() {
        TokenBucketLimiter lim = new TokenBucketLimiter(1, 1);
        assertTrue(lim.tryAcquire("k", 0).allowed());
        RateLimiter.Result r = lim.tryAcquire("k", 0);
        assertFalse(r.allowed());
        assertTrue(r.retryAfterMillis() > 0);
        assertEquals(1, r.limit());
    }

    @Test
    void refillAllowsAcquireAfterTime() {
        TokenBucketLimiter lim = new TokenBucketLimiter(10, 1);
        assertTrue(lim.tryAcquire("k", 0).allowed());
        assertFalse(lim.tryAcquire("k", 0).allowed());
        long oneSecLater = 1_000_000_000L;
        assertTrue(lim.tryAcquire("k", oneSecLater).allowed());
    }

    @Test
    void differentKeysAreIndependent() {
        TokenBucketLimiter lim = new TokenBucketLimiter(1, 1);
        assertTrue(lim.tryAcquire("a", 0).allowed());
        assertTrue(lim.tryAcquire("b", 0).allowed());
    }

    @Test
    void cleanupDoesNotThrow() {
        TokenBucketLimiter lim = new TokenBucketLimiter(1, 1);
        lim.tryAcquire("k", System.nanoTime());
        assertDoesNotThrow(() -> lim.cleanup(0));
    }
}