74 lines
1.9 KiB
Go
74 lines
1.9 KiB
Go
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// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
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// SPDX-License-Identifier: MIT
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package nfsfs
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import (
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"fmt"
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"os"
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"path/filepath"
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"testing"
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)
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// openFDs counts the descriptors the process holds through /proc. The
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// count is a lower bound of live descriptors and good enough to prove a
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// cache does not leak: a thousand operations over one file must not add a
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// thousand descriptors.
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func openFDs(t *testing.T) int {
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t.Helper()
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entries, err := os.ReadDir("/proc/self/fd")
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if err != nil {
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t.Skipf("/proc/self/fd is unavailable: %v", err)
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}
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return len(entries)
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}
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// TestCacheNoDescriptorLeak drives more operations over one file than the
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// cache can hold and requires the process descriptor count to stay flat.
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func TestCacheNoDescriptorLeak(t *testing.T) {
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l, h, _ := cacheTestRoot(t, "leak")
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before := openFDs(t)
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for range 1000 {
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if _, err := l.Read(h, 0, 4); err != nil {
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t.Fatalf("Read: %v", err)
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}
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}
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after := openFDs(t)
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if after-before > 8 {
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t.Fatalf("descriptors grew from %d to %d over 1000 reads", before, after)
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}
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}
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// TestCacheBound holds when many distinct files flow through: after
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// touching twice the bound, at most the bound of cache entries may remain.
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func TestCacheBound(t *testing.T) {
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root := t.TempDir()
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l, err := NewLocal(root)
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if err != nil {
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t.Fatalf("NewLocal: %v", err)
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}
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rh, err := l.Root()
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if err != nil {
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t.Fatalf("Root: %v", err)
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}
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for i := range 2 * fdCacheLimit {
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name := fmt.Sprintf("f%d", i)
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if err := os.WriteFile(filepath.Join(root, name), []byte("x"), 0o644); err != nil {
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t.Fatalf("WriteFile: %v", err)
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}
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h, _, err := l.Lookup(rh, name)
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if err != nil {
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t.Fatalf("Lookup: %v", err)
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}
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if _, err := l.Read(h, 0, 1); err != nil {
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t.Fatalf("Read %s: %v", name, err)
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}
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}
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l.fdMu.Lock()
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n := len(l.fds)
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l.fdMu.Unlock()
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if n > fdCacheLimit {
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t.Fatalf("cache holds %d entries, bound is %d", n, fdCacheLimit)
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}
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}
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