added Cache unit tests for non-trivial functions

d2common/d2cache/cache_test.go

@@ -0,0 +1,83 @@
+package d2cache
+
+import (
+	"testing"
+)
+
+
+func TestCacheInsert(t *testing.T) {
+	cache := CreateCache(1)
+	insertError := cache.Insert("A", "", 1)
+	if insertError != nil {
+		t.Fatalf("Cache insert resulted in unexpected error: %s", insertError)
+	}
+}
+
+func TestCacheInsertUpdatesWeight(t *testing.T) {
+	cache := CreateCache(2)
+	cache.Insert("A", "", 1)
+	cache.Insert("B", "", 1)
+	cache.Insert("budget_exceeded", "", 1)
+
+	if cache.GetWeight() != 2 {
+		t.Fatal("Cache with budget 2 did not correctly set weight after evicting one of three nodes")
+	}
+
+}
+
+func TestCacheInsertDuplicateRejected(t *testing.T) {
+	cache := CreateCache(2)
+	cache.Insert("dupe", "", 1)
+	dupeError := cache.Insert("dupe", "", 1)
+	if dupeError == nil {
+		t.Fatal("Cache insert of duplicate key did not result in any err")
+	}
+}
+
+func TestCacheInsertEvictsLeastRecentlyUsed(t *testing.T) {
+	cache := CreateCache(2)
+	// with a budget of 2, inserting 3 keys should evict the last
+	cache.Insert("evicted", "", 1)
+	cache.Insert("A", "", 1)
+	cache.Insert("B", "", 1)
+
+	_, foundEvicted := cache.Retrieve("evicted")
+	if foundEvicted {
+		t.Fatal("Cache insert did not trigger eviction after weight exceedance")
+	}
+
+	// double check that only 1 one was evicted and not any extra
+	_, foundA := cache.Retrieve("A")
+	_, foundB := cache.Retrieve("B")
+	if !foundA || !foundB {
+		t.Fatal("Cache insert evicted more than necessary")
+	}
+}
+
+func TestCacheInsertEvictsLeastRecentlyRetrieved(t *testing.T) {
+	cache := CreateCache(2)
+	cache.Insert("A", "", 1)
+	cache.Insert("evicted", "", 1)
+
+	// retrieve the oldest node, promoting it head so it is not evicted
+	cache.Retrieve("A")
+
+	// insert once more, exceeding weight capacity
+	cache.Insert("B", "", 1)
+	// now the least recently used key should be evicted
+	_, foundEvicted := cache.Retrieve("evicted")
+	if foundEvicted {
+		t.Fatal("Cache insert did not evict least recently used after weight exceedance")
+	}
+}
+
+func TestClear(t *testing.T) {
+	cache := CreateCache(1)
+	cache.Insert("cleared", "", 1)
+	cache.Clear()
+	_, found := cache.Retrieve("cleared")
+	if found {
+		t.Fatal("Still able to retrieve nodes after cache was cleared")
+	}
+}
+