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// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
package reload
import (
"context"
"errors"
"fmt"
"os"
"path/filepath"
"reflect"
"sync/atomic"
"testing"
"time"
"tailscale.com/tstest"
)
func TestReloader(t *testing.T) {
buf := []byte("hello world")
ctx := context.Background()
r, err := newUnstarted[string](ctx, ReloadOpts[string]{
Logf: t.Logf,
Read: func(context.Context) ([]byte, error) {
return buf, nil
},
Unmarshal: func(b []byte) (string, error) {
return "The value is: " + string(b), nil
},
})
if err != nil {
t.Fatal(err)
}
// We should have an initial value.
const wantInitial = "The value is: hello world"
if v := r.store.Load(); v != wantInitial {
t.Errorf("got initial value %q, want %q", v, wantInitial)
}
// Reloading should result in a new value
buf = []byte("new value")
if err := r.updateOnce(); err != nil {
t.Fatal(err)
}
const wantReload = "The value is: new value"
if v := r.store.Load(); v != wantReload {
t.Errorf("got reloaded value %q, want %q", v, wantReload)
}
}
func TestReloader_InitialError(t *testing.T) {
fakeErr := errors.New("fake error")
ctx := context.Background()
_, err := newUnstarted[string](ctx, ReloadOpts[string]{
Logf: t.Logf,
Read: func(context.Context) ([]byte, error) { return nil, fakeErr },
Unmarshal: func(b []byte) (string, error) { panic("unused because Read fails") },
})
if err == nil {
t.Fatal("expected non-nil error")
}
if !errors.Is(err, fakeErr) {
t.Errorf("wanted errors.Is(%v, fakeErr)=true", err)
}
}
func TestReloader_ReloadError(t *testing.T) {
fakeErr := errors.New("fake error")
shouldError := false
ctx := context.Background()
r, err := newUnstarted[string](ctx, ReloadOpts[string]{
Logf: t.Logf,
Read: func(context.Context) ([]byte, error) {
return []byte("hello"), nil
},
Unmarshal: func(b []byte) (string, error) {
if shouldError {
return "", fakeErr
}
return string(b), nil
},
})
if err != nil {
t.Fatal(err)
}
if got := r.store.Load(); got != "hello" {
t.Fatalf("got value %q, want \"hello\"", got)
}
shouldError = true
if err := r.updateOnce(); err == nil {
t.Errorf("expected error from updateOnce")
}
if got := r.store.Load(); got != "hello" {
t.Fatalf("got value %q, want \"hello\"", got)
}
}
func TestReloader_Run(t *testing.T) {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
var ncalls atomic.Int64
load, err := New[string](ctx, ReloadOpts[string]{
Logf: tstest.WhileTestRunningLogger(t),
Interval: 10 * time.Millisecond,
Read: func(context.Context) ([]byte, error) {
return []byte("hello"), nil
},
Unmarshal: func(b []byte) (string, error) {
callNum := ncalls.Add(1)
if callNum == 3 {
cancel()
}
return fmt.Sprintf("call %d: %s", callNum, b), nil
},
})
if err != nil {
t.Fatal(err)
}
want := "call 1: hello"
if got := load(); got != want {
t.Fatalf("got value %q, want %q", got, want)
}
// Wait for the periodic refresh to cancel our context
select {
case <-ctx.Done():
case <-time.After(10 * time.Second):
t.Fatal("test timed out")
}
// Depending on how goroutines get scheduled, we can either read call 2
// (if we woke up before the run goroutine stores call 3), or call 3
// (if we woke up after the run goroutine stores the next value). Check
// for both.
want1, want2 := "call 2: hello", "call 3: hello"
if got := load(); got != want1 && got != want2 {
t.Fatalf("got value %q, want %q or %q", got, want1, want2)
}
}
func TestFromJSONFile(t *testing.T) {
type testStruct struct {
Value string
Number int
}
fpath := filepath.Join(t.TempDir(), "test.json")
if err := os.WriteFile(fpath, []byte(`{"Value": "hello", "Number": 1234}`), 0600); err != nil {
t.Fatal(err)
}
ctx := context.Background()
r, err := newUnstarted(ctx, FromJSONFile[*testStruct](fpath))
if err != nil {
t.Fatal(err)
}
got := r.store.Load()
want := &testStruct{Value: "hello", Number: 1234}
if !reflect.DeepEqual(got, want) {
t.Errorf("got %+v, want %+v", got, want)
}
}
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