Huawei: clamp battery charge/discharge power to inverter maximum (#30776)

plugin/cached_test.go

@@ -0,0 +1,64 @@
+package plugin
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/benbjohnson/clock"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCachedHitAndExpiry(t *testing.T) {
+	c := clock.NewMock()
+	o := &cachedPlugin{ctx: context.Background(), clock: c, cache: time.Hour}
+
+	var calls int
+	get, err := cachedGetter(o, func(context.Context) (func() (int64, error), error) {
+		return func() (int64, error) {
+			calls++
+			return int64(calls), nil
+		}, nil
+	})
+	require.NoError(t, err)
+
+	// first call reads, subsequent calls within the window are served from cache
+	v, err := get()
+	require.NoError(t, err)
+	require.EqualValues(t, 1, v)
+
+	c.Add(59 * time.Minute)
+	v, err = get()
+	require.NoError(t, err)
+	require.EqualValues(t, 1, v)
+	require.Equal(t, 1, calls)
+
+	// once the cache expires the next call refreshes
+	c.Add(2 * time.Minute)
+	v, err = get()
+	require.NoError(t, err)
+	require.EqualValues(t, 2, v)
+	require.Equal(t, 2, calls)
+}
+
+func TestCachedDoesNotCacheErrors(t *testing.T) {
+	c := clock.NewMock()
+	o := &cachedPlugin{ctx: context.Background(), clock: c, cache: time.Hour}
+
+	var calls int
+	get, err := cachedGetter(o, func(context.Context) (func() (int64, error), error) {
+		return func() (int64, error) {
+			calls++
+			return 0, errors.New("boom")
+		}, nil
+	})
+	require.NoError(t, err)
+
+	// failures must not be cached, so every call retries the source
+	for range 3 {
+		_, err := get()
+		require.Error(t, err)
+	}
+	require.Equal(t, 3, calls)
+}