Start working on tests for disk cache

tools/disk_cache/implementation.go

@@ -138,7 +138,7 @@ func (dc *DiskCache) get(key string, items []string) map[string]string {
 	}
 	for _, x := range items {
 		p := filepath.Join(base, x)
-		if s, err := os.Stat(p); err != nil || !s.IsDir() {
+		if s, err := os.Stat(p); err != nil || s.IsDir() {
 			continue
 		}
 		ans[x] = p
@@ -193,6 +193,11 @@ func (dc *DiskCache) update_timestamp(key string) {
 func (dc *DiskCache) update_accounting(key string, changed int64) (err error) {
 	if err = dc.ensure_entries(); err == nil {
 		t := dc.entry_map[key]
+		if t == nil {
+			t = &Entry{Key: key}
+			dc.entry_map[key] = t
+			dc.entries.SortedEntries = append(dc.entries.SortedEntries, t)
+		}
 		old_size := t.Size
 		t.Size += changed
 		t.Size = max(0, t.Size)

tools/disk_cache/implementation_test.go

@@ -0,0 +1,41 @@
+package disk_cache
+
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/kovidgoyal/kitty/tools/utils"
+)
+
+var _ = fmt.Print
+
+func TestDiskCache(t *testing.T) {
+	tdir := t.TempDir()
+	dc, err := NewDiskCache(tdir, 64)
+	if err != nil {
+		t.Fatal(err)
+	}
+	m := dc.Get("missing", "one", "two")
+	if diff := cmp.Diff(m, make(map[string]string)); diff != "" {
+		t.Fatalf("Unexpected return from missing: %s", diff)
+	}
+	dc.Add("k1", map[string][]byte{"1": []byte("abcd"), "2": []byte("efgh")})
+
+	ad := func(key string, expected map[string]string) {
+		actual := dc.Get(key, utils.Keys(expected)...)
+
+		for k, path := range actual {
+			d, err := os.ReadFile(path)
+			if err != nil {
+				t.Fatal(err)
+			}
+			actual[k] = string(d)
+		}
+		if diff := cmp.Diff(expected, actual); diff != "" {
+			t.Fatalf("Data for %s not equal: %s", key, diff)
+		}
+	}
+	ad("k1", map[string]string{"1": "abcd", "2": "efgh"})
+}