1 files changed, 144 insertions, 0 deletions
diff --git a/pkg/aflow/cache_test.go b/pkg/aflow/cache_test.go
new file mode 100644
index 000000000..244defdd3
--- /dev/null
+++ b/pkg/aflow/cache_test.go
@@ -0,0 +1,144 @@
+// Copyright 2026 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package aflow
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/google/syzkaller/pkg/osutil"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCache(t *testing.T) {
+	var mockedTime time.Time
+	timeNow := func() time.Time {
+		return mockedTime
+	}
+	tempDir := t.TempDir()
+	c, err := newTestCache(t, tempDir, 1<<40, timeNow)
+	require.NoError(t, err)
+	dir1, err := c.Create("foo", "1", func(dir string) error {
+		return osutil.WriteFile(filepath.Join(dir, "bar"), []byte("abc"))
+	})
+	require.NoError(t, err)
+	data, err := os.ReadFile(filepath.Join(dir1, "bar"))
+	require.NoError(t, err)
+	require.Equal(t, data, []byte("abc"))
+	c.Release(dir1)
+
+	dir2, err := c.Create("foo", "1", func(dir string) error {
+		t.Fatal("must not be called")
+		return nil
+	})
+	require.NoError(t, err)
+	require.Equal(t, dir2, dir1)
+	data, err = os.ReadFile(filepath.Join(dir2, "bar"))
+	require.NoError(t, err)
+	require.Equal(t, data, []byte("abc"))
+	c.Release(dir2)
+
+	dir3, err := c.Create("foo", "2", func(dir string) error {
+		return osutil.WriteFile(filepath.Join(dir, "baz"), []byte("def"))
+	})
+	require.NoError(t, err)
+	require.NotEqual(t, dir3, dir1)
+	data, err = os.ReadFile(filepath.Join(dir3, "baz"))
+	require.NoError(t, err)
+	require.Equal(t, data, []byte("def"))
+	c.Release(dir3)
+
+	failedDir := ""
+	dir4, err := c.Create("foo", "3", func(dir string) error {
+		failedDir = dir
+		return fmt.Errorf("failed")
+	})
+	require.Error(t, err)
+	require.Empty(t, dir4)
+	require.False(t, osutil.IsExist(failedDir))
+
+	// Create a new cache, it should pick up the state from disk.
+	c, err = newTestCache(t, tempDir, 1<<40, timeNow)
+	require.NoError(t, err)
+
+	dir5, err := c.Create("foo", "1", func(dir string) error {
+		t.Fatal("must not be called")
+		return nil
+	})
+	require.NoError(t, err)
+	require.Equal(t, dir5, dir1)
+	data, err = os.ReadFile(filepath.Join(dir5, "bar"))
+	require.NoError(t, err)
+	require.Equal(t, data, []byte("abc"))
+	c.Release(dir5)
+
+	// Model an incomplete dir without metadata, it should be removed.
+	strayDir := filepath.Join(tempDir, "a", "b")
+	require.NoError(t, osutil.MkdirAll(strayDir))
+	require.NoError(t, osutil.WriteFile(filepath.Join(strayDir, "foo"), []byte("foo")))
+
+	// With 0 max size everything unused should be purged.
+	_, err = newTestCache(t, tempDir, 0, timeNow)
+	require.NoError(t, err)
+	require.False(t, osutil.IsExist(dir1))
+	require.False(t, osutil.IsExist(dir3))
+	require.False(t, osutil.IsExist(strayDir))
+
+	// Test incremental purging of files.
+	c, err = newTestCache(t, tempDir, 100<<10, timeNow)
+	require.NoError(t, err)
+
+	mockedTime = mockedTime.Add(time.Minute)
+	dir6, err := c.Create("foo", "1", func(dir string) error {
+		return osutil.WriteFile(filepath.Join(dir, "bar"), bytes.Repeat([]byte{'a'}, 5<<10))
+	})
+	require.NoError(t, err)
+	c.Release(dir6)
+
+	mockedTime = mockedTime.Add(time.Minute)
+	dir7, err := c.Create("foo", "2", func(dir string) error {
+		return osutil.WriteFile(filepath.Join(dir, "bar"), bytes.Repeat([]byte{'a'}, 5<<10))
+	})
+	require.NoError(t, err)
+	c.Release(dir7)
+
+	mockedTime = mockedTime.Add(time.Minute)
+	dir8, err := c.Create("foo", "3", func(dir string) error {
+		return osutil.WriteFile(filepath.Join(dir, "bar"), bytes.Repeat([]byte{'a'}, 60<<10))
+	})
+	require.NoError(t, err)
+	c.Release(dir8)
+
+	// Force update of the last access time for the first dir.
+	mockedTime = mockedTime.Add(time.Minute)
+	dir9, err := c.Create("foo", "1", func(dir string) error {
+		t.Fatal("must not be called")
+		return nil
+	})
+	require.NoError(t, err)
+	require.Equal(t, dir6, dir9)
+	c.Release(dir9)
+
+	// Both dirs should exist since they should fit into cache size.
+	require.True(t, osutil.IsExist(dir6))
+	require.True(t, osutil.IsExist(dir7))
+	require.True(t, osutil.IsExist(dir8))
+
+	mockedTime = mockedTime.Add(time.Minute)
+	dir10, err := c.Create("foo", "4", func(dir string) error {
+		return osutil.WriteFile(filepath.Join(dir, "bar"), bytes.Repeat([]byte{'a'}, 60<<10))
+	})
+	require.NoError(t, err)
+	c.Release(dir10)
+
+	// Two oldest dirs should be purged.
+	require.True(t, osutil.IsExist(dir6))
+	require.False(t, osutil.IsExist(dir7))
+	require.False(t, osutil.IsExist(dir8))
+	require.True(t, osutil.IsExist(dir10))
+}