--- /dev/null
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package memoize_test
+
+import (
+ "context"
+ "strings"
+ "testing"
+
+ "golang.org/x/tools/internal/memoize"
+)
+
+func TestGet(t *testing.T) {
+ s := &memoize.Store{}
+ g := s.Generation("x")
+
+ evaled := 0
+
+ h := g.Bind("key", func(context.Context, memoize.Arg) interface{} {
+ evaled++
+ return "res"
+ }, nil)
+ expectGet(t, h, g, "res")
+ expectGet(t, h, g, "res")
+ if evaled != 1 {
+ t.Errorf("got %v calls to function, wanted 1", evaled)
+ }
+}
+
+func expectGet(t *testing.T, h *memoize.Handle, g *memoize.Generation, wantV interface{}) {
+ t.Helper()
+ gotV, gotErr := h.Get(context.Background(), g, nil)
+ if gotV != wantV || gotErr != nil {
+ t.Fatalf("Get() = %v, %v, wanted %v, nil", gotV, gotErr, wantV)
+ }
+}
+
+func expectGetError(t *testing.T, h *memoize.Handle, g *memoize.Generation, substr string) {
+ gotV, gotErr := h.Get(context.Background(), g, nil)
+ if gotErr == nil || !strings.Contains(gotErr.Error(), substr) {
+ t.Fatalf("Get() = %v, %v, wanted err %q", gotV, gotErr, substr)
+ }
+}
+
+func TestGenerations(t *testing.T) {
+ s := &memoize.Store{}
+ // Evaluate key in g1.
+ g1 := s.Generation("g1")
+ h1 := g1.Bind("key", func(context.Context, memoize.Arg) interface{} { return "res" }, nil)
+ expectGet(t, h1, g1, "res")
+
+ // Get key in g2. It should inherit the value from g1.
+ g2 := s.Generation("g2")
+ h2 := g2.Bind("key", func(context.Context, memoize.Arg) interface{} {
+ t.Fatal("h2 should not need evaluation")
+ return "error"
+ }, nil)
+ expectGet(t, h2, g2, "res")
+
+ // With g1 destroyed, g2 should still work.
+ g1.Destroy()
+ expectGet(t, h2, g2, "res")
+
+ // With all generations destroyed, key should be re-evaluated.
+ g2.Destroy()
+ g3 := s.Generation("g3")
+ h3 := g3.Bind("key", func(context.Context, memoize.Arg) interface{} { return "new res" }, nil)
+ expectGet(t, h3, g3, "new res")
+}
+
+func TestCleanup(t *testing.T) {
+ s := &memoize.Store{}
+ g1 := s.Generation("g1")
+ v1 := false
+ v2 := false
+ cleanup := func(v interface{}) {
+ *(v.(*bool)) = true
+ }
+ h1 := g1.Bind("key1", func(context.Context, memoize.Arg) interface{} {
+ return &v1
+ }, nil)
+ h2 := g1.Bind("key2", func(context.Context, memoize.Arg) interface{} {
+ return &v2
+ }, cleanup)
+ expectGet(t, h1, g1, &v1)
+ expectGet(t, h2, g1, &v2)
+ g2 := s.Generation("g2")
+ g2.Inherit(h1, h2)
+
+ g1.Destroy()
+ expectGet(t, h1, g2, &v1)
+ expectGet(t, h2, g2, &v2)
+ for k, v := range map[string]*bool{"key1": &v1, "key2": &v2} {
+ if got, want := *v, false; got != want {
+ t.Errorf("after destroying g1, bound value %q is cleaned up", k)
+ }
+ }
+ g2.Destroy()
+ if got, want := v1, false; got != want {
+ t.Error("after destroying g2, v1 is cleaned up")
+ }
+ if got, want := v2, true; got != want {
+ t.Error("after destroying g2, v2 is not cleaned up")
+ }
+}