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fleetd/bridged/src/test/java/dev/ltms/bridged/placement/PlacementPolicyTest.java
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CB-585: maxLoad: 0 caps a profile at zero, negative refused at load
2026-08-15 15:38:50 +02:00

371 lines
16 KiB
Java

package dev.ltms.bridged.placement;
import org.junit.jupiter.api.Test;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;
import static org.junit.jupiter.api.Assertions.*;
/**
* Unit tests for the placement policies. They run with no herdr and no launcher — pure selection
* logic exercised through the descriptor type so CB-308 host expansion will not need to rewrite
* these assertions.
*/
class PlacementPolicyTest {
private static Function<String, Integer> noSessions() {
return name -> 0;
}
private static PlacementContext ctx(List<PlacementCandidate> candidates,
Function<String, Integer> liveCount,
Set<String> unreachable) {
return ctx(candidates, liveCount, unreachable, Set.of());
}
private static PlacementContext ctx(List<PlacementCandidate> candidates,
Function<String, Integer> liveCount,
Set<String> unreachable, Set<String> quarantined) {
return new PlacementContext("b", candidates, liveCount, unreachable, quarantined);
}
private static PlacementContext ctx(List<PlacementCandidate> candidates,
Function<String, Integer> liveCount) {
return ctx(candidates, liveCount, Set.of());
}
@Test
void fixedReturnsDefaultEvenIfOtherProfilesExist() {
PlacementPolicy policy = PlacementPolicies.fixed();
PlacementContext ctx = ctx(List.of(
PlacementCandidate.profile("a"),
PlacementCandidate.profile("b")), noSessions());
assertEquals("b", policy.select(ctx).profile());
}
@Test
void fixedFallsBackToFirstCandidateWhenNoDefault() {
PlacementPolicy policy = PlacementPolicies.fixed();
PlacementContext ctx = new PlacementContext(null,
List.of(PlacementCandidate.profile("a"), PlacementCandidate.profile("b")),
noSessions(), Set.of(), Set.of());
assertEquals("a", policy.select(ctx).profile());
}
@Test
void fixedThrowsWhenNoProfilesAndNoDefault() {
PlacementPolicy policy = PlacementPolicies.fixed();
PlacementContext ctx = new PlacementContext(null, List.of(), noSessions(), Set.of(), Set.of());
assertThrows(PlacementException.class, () -> policy.select(ctx));
}
@Test
void fixedSkipsQuarantinedDefault() {
PlacementPolicy policy = PlacementPolicies.fixed();
PlacementContext ctx = new PlacementContext("b",
List.of(PlacementCandidate.profile("a"), PlacementCandidate.profile("b")),
noSessions(), Set.of(), Set.of("b"));
assertEquals("a", policy.select(ctx).profile(),
"the default 'b' is quarantined, so fixed falls through to the first un-quarantined candidate");
}
@Test
void fixedThrowsWhenDefaultAndEveryCandidateQuarantined() {
PlacementPolicy policy = PlacementPolicies.fixed();
PlacementContext ctx = new PlacementContext("b",
List.of(PlacementCandidate.profile("a"), PlacementCandidate.profile("b")),
noSessions(), Set.of(), Set.of("a", "b"));
PlacementException e = assertThrows(PlacementException.class, () -> policy.select(ctx));
assertTrue(e.getMessage().contains("quarantined"), e.getMessage());
}
@Test
void roundRobinCyclesThroughAvailableProfiles() {
PlacementPolicy policy = PlacementPolicies.roundRobin();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a"),
PlacementCandidate.profile("b"),
PlacementCandidate.profile("c"));
assertEquals("a", policy.select(ctx(candidates, noSessions())).profile());
assertEquals("b", policy.select(ctx(candidates, noSessions())).profile());
assertEquals("c", policy.select(ctx(candidates, noSessions())).profile());
assertEquals("a", policy.select(ctx(candidates, noSessions())).profile());
}
@Test
void roundRobinSkipsProfilesAtMaxLoad() {
PlacementPolicy policy = PlacementPolicies.roundRobin();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 1.0f, 2),
PlacementCandidate.profile("b", 1.0f, null));
Function<String, Integer> liveCount = Map.of("a", 2)::get;
for (int i = 0; i < 5; i++) {
assertEquals("b", policy.select(ctx(candidates, liveCount)).profile());
}
}
@Test
void roundRobinSkipsQuarantinedProfiles() {
PlacementPolicy policy = PlacementPolicies.roundRobin();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a"),
PlacementCandidate.profile("b"));
PlacementContext ctx = ctx(candidates, noSessions(), Set.of(), Set.of("a"));
for (int i = 0; i < 5; i++) {
assertEquals("b", policy.select(ctx).profile(), "a is quarantined, so every pick lands on b");
}
}
@Test
void roundRobinThrowsWhenAllAtMaxLoad() {
PlacementPolicy policy = PlacementPolicies.roundRobin();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 1.0f, 1),
PlacementCandidate.profile("b", 1.0f, 1));
Function<String, Integer> liveCount = Map.of("a", 1, "b", 1)::get;
PlacementException e = assertThrows(PlacementException.class,
() -> policy.select(ctx(candidates, liveCount)));
assertTrue(e.getMessage().contains("maxLoad"), e.getMessage());
}
@Test
void weightedAlternatesEvenlyWithEqualWeights() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 0.5f, null),
PlacementCandidate.profile("b", 0.5f, null));
int a = 0, b = 0;
for (int i = 0; i < 100; i++) {
String p = policy.select(ctx(candidates, noSessions())).profile();
if ("a".equals(p)) a++;
else if ("b".equals(p)) b++;
}
assertEquals(50, a, "equal weights should split 50/50");
assertEquals(50, b);
}
@Test
void weightedHoldsThreeToOneRatio() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 0.75f, null),
PlacementCandidate.profile("b", 0.25f, null));
int a = 0, b = 0;
for (int i = 0; i < 40; i++) {
String p = policy.select(ctx(candidates, noSessions())).profile();
if ("a".equals(p)) a++;
else if ("b".equals(p)) b++;
}
assertEquals(30, a, "0.75/0.25 should yield a 3:1 ratio over a multiple of 4");
assertEquals(10, b);
}
@Test
void weightedSkipsProfileAtMaxLoad() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 1.0f, 1),
PlacementCandidate.profile("b", 1.0f, null));
Function<String, Integer> liveCount = name -> "a".equals(name) ? 1 : 0;
for (int i = 0; i < 5; i++) {
assertEquals("b", policy.select(ctx(candidates, liveCount)).profile());
}
}
@Test
void weightedThrowsWhenAllAtMaxLoad() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 1.0f, 1),
PlacementCandidate.profile("b", 1.0f, 1));
Function<String, Integer> liveCount = name -> 1;
PlacementException e = assertThrows(PlacementException.class,
() -> policy.select(ctx(candidates, liveCount)));
assertTrue(e.getMessage().contains("maxLoad"), e.getMessage());
}
@Test
void weightedSkipsQuarantinedProfile() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 1.0f, null),
PlacementCandidate.profile("b", 1.0f, null));
PlacementContext ctx = ctx(candidates, noSessions(), Set.of(), Set.of("a"));
for (int i = 0; i < 5; i++) {
assertEquals("b", policy.select(ctx).profile(), "a is quarantined, so every pick lands on b");
}
}
@Test
void weightedThrowsWhenAllQuarantined() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a"),
PlacementCandidate.profile("b"));
PlacementException e = assertThrows(PlacementException.class,
() -> policy.select(ctx(candidates, noSessions(), Set.of(), Set.of("a", "b"))));
assertTrue(e.getMessage().contains("quarantined"), e.getMessage());
}
@Test
void weightedThrowsWhenAllUnreachable() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a"),
PlacementCandidate.profile("b"));
PlacementException e = assertThrows(PlacementException.class,
() -> policy.select(ctx(candidates, noSessions(), Set.of("a", "b"))));
assertTrue(e.getMessage().contains("unreachable"), e.getMessage());
}
@Test
void mixedExclusionMessageNamesBothReasons() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 1.0f, 1),
PlacementCandidate.profile("b", 1.0f, null));
Function<String, Integer> liveCount = name -> "a".equals(name) ? 1 : 0;
Set<String> unreachable = new HashSet<>();
unreachable.add("b");
PlacementException e = assertThrows(PlacementException.class,
() -> policy.select(ctx(candidates, liveCount, unreachable)));
assertTrue(e.getMessage().contains("1 at maxLoad"), e.getMessage());
assertTrue(e.getMessage().contains("1 unreachable"), e.getMessage());
}
// --- CB-554: weight <= 0 excludes a candidate from automatic selection ------------------
@Test
void weightedSkipsWeightZeroProfile() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 0.0f, null),
PlacementCandidate.profile("b", 1.0f, null));
for (int i = 0; i < 5; i++) {
assertEquals("b", policy.select(ctx(candidates, noSessions())).profile(),
"a has weight 0, so every pick lands on b");
}
}
@Test
void weightedThrowsWhenAllWeightZero() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 0.0f, null),
PlacementCandidate.profile("b", 0.0f, null));
PlacementException e = assertThrows(PlacementException.class,
() -> policy.select(ctx(candidates, noSessions())));
assertTrue(e.getMessage().contains("weight 0"), e.getMessage());
}
@Test
void weightedTreatsNegativeWeightAsExcludedNotError() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", -1.0f, null),
PlacementCandidate.profile("b", 1.0f, null));
for (int i = 0; i < 5; i++) {
assertEquals("b", policy.select(ctx(candidates, noSessions())).profile(),
"a has a negative weight, so it is excluded like weight 0 — never picked, never an error");
}
}
@Test
void weightZeroAndQuarantinedIsNotDoubleCounted() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 0.0f, null),
PlacementCandidate.profile("b", 1.0f, null),
PlacementCandidate.profile("c", 1.0f, null));
// a is BOTH weight-0 and quarantined; b and c are quarantined only. If a were counted
// into both buckets, "quarantined" would read 3 (or the arithmetic would go negative)
// instead of the true count of 2 candidates actually quarantined.
PlacementContext mixedCtx = ctx(candidates, noSessions(), Set.of(), Set.of("a", "b", "c"));
PlacementException e = assertThrows(PlacementException.class, () -> policy.select(mixedCtx));
assertTrue(e.getMessage().contains("1 weight-0"), e.getMessage());
assertTrue(e.getMessage().contains("2 quarantined"), e.getMessage());
assertTrue(e.getMessage().contains("0 remaining"), e.getMessage());
}
@Test
void roundRobinSkipsWeightZeroProfiles() {
PlacementPolicy policy = PlacementPolicies.roundRobin();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 0.0f, null),
PlacementCandidate.profile("b", 1.0f, null));
for (int i = 0; i < 5; i++) {
assertEquals("b", policy.select(ctx(candidates, noSessions())).profile(),
"a has weight 0, so every pick lands on b");
}
}
@Test
void roundRobinThrowsWhenAllWeightZero() {
PlacementPolicy policy = PlacementPolicies.roundRobin();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 0.0f, null),
PlacementCandidate.profile("b", 0.0f, null));
PlacementException e = assertThrows(PlacementException.class,
() -> policy.select(ctx(candidates, noSessions())));
assertTrue(e.getMessage().contains("weight 0"), e.getMessage());
}
@Test
void fixedSkipsWeightZeroDefault() {
PlacementPolicy policy = PlacementPolicies.fixed();
PlacementContext ctx = new PlacementContext("b",
List.of(PlacementCandidate.profile("a", 1.0f, null),
PlacementCandidate.profile("b", 0.0f, null)),
noSessions(), Set.of(), Set.of());
assertEquals("a", policy.select(ctx).profile(),
"the default 'b' has weight 0, so fixed falls through to the first available candidate");
}
@Test
void fixedThrowsWhenDefaultAndEveryCandidateWeightZero() {
PlacementPolicy policy = PlacementPolicies.fixed();
PlacementContext ctx = new PlacementContext("b",
List.of(PlacementCandidate.profile("a", 0.0f, null),
PlacementCandidate.profile("b", 0.0f, null)),
noSessions(), Set.of(), Set.of());
PlacementException e = assertThrows(PlacementException.class, () -> policy.select(ctx));
assertTrue(e.getMessage().contains("weight 0"), e.getMessage());
}
@Test
void unknownPolicyNameThrows() {
assertThrows(IllegalArgumentException.class, () -> PlacementPolicies.fromName("random"));
}
// --- CB-585: maxLoad 0 caps a profile at zero live members, even with nothing live yet -----
@Test
void weightedSkipsMaxLoadZeroProfileEvenWithZeroLiveWorkers() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 1.0f, 0),
PlacementCandidate.profile("b", 1.0f, null));
Function<String, Integer> liveCount = _ -> 0;
for (int i = 0; i < 5; i++) {
assertEquals("b", policy.select(ctx(candidates, liveCount)).profile(),
"a has maxLoad 0, so it is already at its cap with nobody live — every pick lands on b");
}
}
@Test
void weightedThrowsWhenAllMaxLoadZero() {
PlacementPolicy policy = PlacementPolicies.weighted();
List<PlacementCandidate> candidates = List.of(
PlacementCandidate.profile("a", 1.0f, 0),
PlacementCandidate.profile("b", 1.0f, 0));
Function<String, Integer> liveCount = _ -> 0;
PlacementException e = assertThrows(PlacementException.class,
() -> policy.select(ctx(candidates, liveCount)));
assertTrue(e.getMessage().contains("maxLoad"), e.getMessage());
}
}