1 files changed, 157 insertions, 0 deletions
diff --git a/pkg/sentry/fs/dirent_cache_test.go b/pkg/sentry/fs/dirent_cache_test.go
new file mode 100644
index 000000000..82b7f6bd5
--- /dev/null
+++ b/pkg/sentry/fs/dirent_cache_test.go
@@ -0,0 +1,157 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fs
+
+import (
+	"testing"
+)
+
+func TestDirentCache(t *testing.T) {
+	const maxSize = 5
+
+	c := NewDirentCache(maxSize)
+
+	// Size starts at 0.
+	if got, want := c.Size(), uint64(0); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+
+	// Create a Dirent d.
+	d := NewNegativeDirent("")
+
+	// c does not contain d.
+	if got, want := c.contains(d), false; got != want {
+		t.Errorf("c.contains(d) got %v want %v", got, want)
+	}
+
+	// Add d to the cache.
+	c.Add(d)
+
+	// Size is now 1.
+	if got, want := c.Size(), uint64(1); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+
+	// c contains d.
+	if got, want := c.contains(d), true; got != want {
+		t.Errorf("c.contains(d) got %v want %v", got, want)
+	}
+
+	// Add maxSize-1 more elements.  d should be oldest element.
+	for i := 0; i < maxSize-1; i++ {
+		c.Add(NewNegativeDirent(""))
+	}
+
+	// Size is maxSize.
+	if got, want := c.Size(), uint64(maxSize); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+
+	// c contains d.
+	if got, want := c.contains(d), true; got != want {
+		t.Errorf("c.contains(d) got %v want %v", got, want)
+	}
+
+	// "Bump" d to the front by re-adding it.
+	c.Add(d)
+
+	// Size is maxSize.
+	if got, want := c.Size(), uint64(maxSize); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+
+	// c contains d.
+	if got, want := c.contains(d), true; got != want {
+		t.Errorf("c.contains(d) got %v want %v", got, want)
+	}
+
+	// Add maxSize-1 more elements.  d should again be oldest element.
+	for i := 0; i < maxSize-1; i++ {
+		c.Add(NewNegativeDirent(""))
+	}
+
+	// Size is maxSize.
+	if got, want := c.Size(), uint64(maxSize); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+
+	// c contains d.
+	if got, want := c.contains(d), true; got != want {
+		t.Errorf("c.contains(d) got %v want %v", got, want)
+	}
+
+	// Add one more element, which will bump d from the cache.
+	c.Add(NewNegativeDirent(""))
+
+	// Size is maxSize.
+	if got, want := c.Size(), uint64(maxSize); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+
+	// c does not contain d.
+	if got, want := c.contains(d), false; got != want {
+		t.Errorf("c.contains(d) got %v want %v", got, want)
+	}
+
+	// Invalidating causes size to be 0 and list to be empty.
+	c.Invalidate()
+	if got, want := c.Size(), uint64(0); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+	if got, want := c.list.Empty(), true; got != want {
+		t.Errorf("c.list.Empty() got %v, want %v", got, want)
+	}
+
+	// Fill cache with maxSize dirents.
+	for i := 0; i < maxSize; i++ {
+		c.Add(NewNegativeDirent(""))
+	}
+}
+
+// TestNilDirentCache tests that a nil cache supports all cache operations, but
+// treats them as noop.
+func TestNilDirentCache(t *testing.T) {
+	// Create a nil cache.
+	var c *DirentCache
+
+	// Size is zero.
+	if got, want := c.Size(), uint64(0); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+
+	// Call Add.
+	c.Add(NewNegativeDirent(""))
+
+	// Size is zero.
+	if got, want := c.Size(), uint64(0); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+
+	// Call Remove.
+	c.Remove(NewNegativeDirent(""))
+
+	// Size is zero.
+	if got, want := c.Size(), uint64(0); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+
+	// Call Invalidate.
+	c.Invalidate()
+
+	// Size is zero.
+	if got, want := c.Size(), uint64(0); got != want {
+		t.Errorf("c.Size() got %v, want %v", got, want)
+	}
+}