From aecdde724f1cc04f024bb44dd15910cee704eed5 Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Fri, 27 Feb 2026 17:08:56 +0200
Subject: flamegraph: add live trie unit coverage

---
 internal/flamegraph/livetrie_test.go | 170 +++++++++++++++++++++++++++++++++++
 1 file changed, 170 insertions(+)
 create mode 100644 internal/flamegraph/livetrie_test.go

(limited to 'internal/flamegraph')

diff --git a/internal/flamegraph/livetrie_test.go b/internal/flamegraph/livetrie_test.go
new file mode 100644
index 0000000..6982a86
--- /dev/null
+++ b/internal/flamegraph/livetrie_test.go
@@ -0,0 +1,170 @@
+package flamegraph
+
+import (
+	"bytes"
+	"encoding/json"
+	"ior/internal/event"
+	"ior/internal/file"
+	"ior/internal/types"
+	"sync"
+	"testing"
+)
+
+func TestLiveTrieIngestAndSnapshotRoundTrip(t *testing.T) {
+	lt := NewLiveTrie([]string{"comm", "pid"}, "count")
+	lt.Ingest(newTestPair("svc", 42, 1001, "/tmp/a", 1, 2, 3))
+
+	snap := decodeLiveSnapshot(t, lt)
+	if snap.Total != 1 {
+		t.Fatalf("root total = %d, want 1", snap.Total)
+	}
+	leaf := findSnapshotPath(t, &snap, "svc", "42")
+	if leaf.Value != 1 {
+		t.Fatalf("leaf value = %d, want 1", leaf.Value)
+	}
+	if leaf.Total != 1 {
+		t.Fatalf("leaf total = %d, want 1", leaf.Total)
+	}
+}
+
+func TestLiveTrieIngestIsAdditive(t *testing.T) {
+	lt := NewLiveTrie([]string{"path"}, "bytes")
+	lt.Ingest(newTestPair("svc", 42, 1001, "/tmp/a", 1, 2, 10))
+	lt.Ingest(newTestPair("svc", 42, 1001, "/tmp/a", 3, 4, 15))
+
+	snap := decodeLiveSnapshot(t, lt)
+	leaf := findSnapshotPath(t, &snap, "/tmp", "/a")
+	if leaf.Value != 25 {
+		t.Fatalf("leaf bytes value = %d, want 25", leaf.Value)
+	}
+	if snap.Total != 25 {
+		t.Fatalf("root total = %d, want 25", snap.Total)
+	}
+}
+
+func TestLiveTrieVersionIncrementsPerIngest(t *testing.T) {
+	lt := NewLiveTrie([]string{"comm"}, "count")
+	if got := lt.Version(); got != 0 {
+		t.Fatalf("initial version = %d, want 0", got)
+	}
+	lt.Ingest(newTestPair("svc", 42, 1001, "/tmp/a", 1, 1, 1))
+	lt.Ingest(newTestPair("svc", 42, 1002, "/tmp/b", 1, 1, 1))
+
+	if got := lt.Version(); got != 2 {
+		t.Fatalf("version = %d, want 2", got)
+	}
+}
+
+func TestLiveTrieSnapshotJSONCaching(t *testing.T) {
+	lt := NewLiveTrie([]string{"comm"}, "count")
+	lt.Ingest(newTestPair("svc", 42, 1001, "/tmp/a", 1, 1, 1))
+
+	first, version1 := lt.SnapshotJSON()
+	second, version2 := lt.SnapshotJSON()
+
+	if version1 != version2 {
+		t.Fatalf("versions differ: %d != %d", version1, version2)
+	}
+	if !bytes.Equal(first, second) {
+		t.Fatalf("snapshot bytes differ across cached call")
+	}
+}
+
+func TestLiveTrieSnapshotJSONPrunesTinyNodes(t *testing.T) {
+	lt := NewLiveTrie([]string{"comm"}, "count")
+	for i := 0; i < 2000; i++ {
+		lt.Ingest(newTestPair("big", 42, uint32(1000+i), "/tmp/a", 1, 1, 1))
+	}
+	lt.Ingest(newTestPair("tiny", 42, 99999, "/tmp/z", 1, 1, 1))
+
+	snap := decodeLiveSnapshot(t, lt)
+	if findSnapshotChild(&snap, "big") == nil {
+		t.Fatalf("expected big node in snapshot")
+	}
+	if findSnapshotChild(&snap, "tiny") != nil {
+		t.Fatalf("tiny node should be pruned at <0.1%% of root total")
+	}
+}
+
+func TestLiveTrieConcurrentIngestAndSnapshot(t *testing.T) {
+	lt := NewLiveTrie([]string{"comm", "pid"}, "count")
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	go func() {
+		defer wg.Done()
+		for i := 0; i < 500; i++ {
+			lt.Ingest(newTestPair("svc", 42, uint32(1000+i), "/tmp/a", 1, 1, 1))
+		}
+	}()
+
+	go func() {
+		defer wg.Done()
+		for i := 0; i < 500; i++ {
+			payload, _ := lt.SnapshotJSON()
+			var snap trieSnapshot
+			if err := json.Unmarshal(payload, &snap); err != nil {
+				t.Errorf("unmarshal snapshot: %v", err)
+				return
+			}
+		}
+	}()
+
+	wg.Wait()
+	if lt.Version() == 0 {
+		t.Fatalf("expected version > 0 after concurrent ingest")
+	}
+}
+
+func newTestPair(comm string, pid uint32, tid uint32, path string, duration uint64, gap uint64, bytesCnt uint64) *event.Pair {
+	enter := &types.OpenEvent{
+		TraceId: types.SYS_ENTER_OPENAT,
+		Pid:     pid,
+		Tid:     tid,
+	}
+	exit := &types.RetEvent{
+		TraceId: types.SYS_EXIT_OPENAT,
+		Pid:     pid,
+		Tid:     tid,
+	}
+	pair := event.NewPair(enter)
+	pair.ExitEv = exit
+	pair.File = file.NewFd(3, path, 0)
+	pair.Comm = comm
+	pair.Duration = duration
+	pair.DurationToPrev = gap
+	pair.Bytes = bytesCnt
+	return pair
+}
+
+func decodeLiveSnapshot(t *testing.T, lt *LiveTrie) trieSnapshot {
+	t.Helper()
+	payload, _ := lt.SnapshotJSON()
+	var snap trieSnapshot
+	if err := json.Unmarshal(payload, &snap); err != nil {
+		t.Fatalf("unmarshal snapshot: %v", err)
+	}
+	return snap
+}
+
+func findSnapshotPath(t *testing.T, root *trieSnapshot, names ...string) *trieSnapshot {
+	t.Helper()
+	node := root
+	for _, name := range names {
+		node = findSnapshotChild(node, name)
+		if node == nil {
+			t.Fatalf("missing snapshot node %q", name)
+		}
+	}
+	return node
+}
+
+func findSnapshotChild(node *trieSnapshot, name string) *trieSnapshot {
+	for _, child := range node.Children {
+		if child.Name == name {
+			return child
+		}
+	}
+	return nil
+}
-- 
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