Added tests and readme

internal/quorum/manager_test.go

@@ -0,0 +1,146 @@
+package quorum
+
+import (
+	"testing"
+	"time"
+
+	"github.com/jasper/quptime/internal/config"
+	"github.com/jasper/quptime/internal/transport"
+)
+
+func threeNode(self string) (*config.ClusterConfig, *Manager) {
+	cluster := &config.ClusterConfig{Peers: []config.PeerInfo{
+		{NodeID: "a"}, {NodeID: "b"}, {NodeID: "c"},
+	}}
+	return cluster, New(self, cluster, nil)
+}
+
+func TestSoloNodeElectsItself(t *testing.T) {
+	cluster := &config.ClusterConfig{}
+	m := New("only", cluster, nil)
+	m.markLive("only")
+	m.recomputeMaster()
+	if m.Master() != "only" {
+		t.Errorf("Master=%q want %q", m.Master(), "only")
+	}
+	if !m.HasQuorum() {
+		t.Error("solo node should have quorum")
+	}
+	if m.Term() != 1 {
+		t.Errorf("Term=%d want 1 after first election", m.Term())
+	}
+}
+
+func TestThreeNodeElectsLowestNodeID(t *testing.T) {
+	_, m := threeNode("b")
+	m.markLive("a")
+	m.markLive("b")
+	m.markLive("c")
+	m.recomputeMaster()
+	if got := m.Master(); got != "a" {
+		t.Errorf("Master=%q want a", got)
+	}
+	if !m.HasQuorum() {
+		t.Error("expected quorum with 3 live of 3")
+	}
+}
+
+func TestNoQuorumClearsMaster(t *testing.T) {
+	_, m := threeNode("b")
+	m.markLive("b")
+	m.recomputeMaster()
+	if m.Master() != "" {
+		t.Errorf("Master=%q want empty (no quorum)", m.Master())
+	}
+	if m.HasQuorum() {
+		t.Error("1 of 3 live should not be quorum")
+	}
+}
+
+func TestTermBumpsOnMasterChange(t *testing.T) {
+	_, m := threeNode("b")
+	m.markLive("a")
+	m.markLive("b")
+	m.recomputeMaster()
+	termBefore := m.Term()
+	masterBefore := m.Master()
+	if masterBefore != "a" {
+		t.Fatalf("expected initial master a, got %q", masterBefore)
+	}
+
+	// "a" goes dead — we and "c" join up.
+	m.mu.Lock()
+	delete(m.lastSeen, "a")
+	m.mu.Unlock()
+	m.markLive("c")
+	m.recomputeMaster()
+	if m.Master() != "b" {
+		t.Errorf("after a-fail Master=%q want b", m.Master())
+	}
+	if m.Term() <= termBefore {
+		t.Errorf("Term did not bump: before=%d after=%d", termBefore, m.Term())
+	}
+}
+
+func TestHandleHeartbeatMarksSenderLive(t *testing.T) {
+	cluster, m := threeNode("a")
+	_ = cluster
+	resp := m.HandleHeartbeat(transport.HeartbeatRequest{
+		FromNodeID: "b",
+		Term:       7,
+		MasterID:   "a",
+		Version:    3,
+	})
+	if resp.NodeID != "a" {
+		t.Errorf("response NodeID=%q want a", resp.NodeID)
+	}
+	if _, ok := m.Liveness()["b"]; !ok {
+		t.Error("sender was not recorded live")
+	}
+}
+
+func TestDeadAfterEvictsStaleLiveness(t *testing.T) {
+	_, m := threeNode("a")
+	m.deadAfter = 50 * time.Millisecond
+	m.markLive("a")
+	m.markLive("b")
+	m.markLive("c")
+	m.recomputeMaster()
+	if m.Master() != "a" {
+		t.Fatal("expected initial master a")
+	}
+
+	// Wait past the dead-after window — only self remains live.
+	time.Sleep(120 * time.Millisecond)
+	m.markLive("a")
+	m.recomputeMaster()
+	if m.Master() != "" {
+		t.Errorf("expected no master after peers timed out, got %q", m.Master())
+	}
+}
+
+func TestVersionObserverFiresOnHigherVersion(t *testing.T) {
+	cluster := &config.ClusterConfig{Version: 2}
+	m := New("a", cluster, nil)
+
+	var notified struct {
+		peerID  string
+		peerVer uint64
+		count   int
+	}
+	m.SetVersionObserver(func(peerID, _ string, peerVer uint64) {
+		notified.peerID = peerID
+		notified.peerVer = peerVer
+		notified.count++
+	})
+
+	m.maybeNotifyVersion("b", 5)
+	if notified.count != 1 || notified.peerID != "b" || notified.peerVer != 5 {
+		t.Errorf("expected observer fired with b=5, got %+v", notified)
+	}
+
+	m.maybeNotifyVersion("b", 1)
+	if notified.count != 1 {
+		t.Errorf("observer fired for stale version, count=%d", notified.count)
+	}
+}