util: add waitmap for target synchronization

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

util/waitmap/waitmap_test.go

@@ -0,0 +1,64 @@
+package waitmap
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetAfter(t *testing.T) {
+	m := New()
+
+	m.Set("foo", "bar")
+	m.Set("bar", "baz")
+
+	ctx := context.TODO()
+	v, err := m.Get(ctx, "foo", "bar")
+	require.NoError(t, err)
+
+	require.Equal(t, 2, len(v))
+	require.Equal(t, "bar", v["foo"])
+	require.Equal(t, "baz", v["bar"])
+
+	v, err = m.Get(ctx, "foo")
+	require.NoError(t, err)
+	require.Equal(t, 1, len(v))
+	require.Equal(t, "bar", v["foo"])
+}
+
+func TestTimeout(t *testing.T) {
+	m := New()
+
+	m.Set("foo", "bar")
+
+	ctx, cancel := context.WithTimeout(context.TODO(), 100*time.Millisecond)
+	defer cancel()
+
+	_, err := m.Get(ctx, "bar")
+	require.Error(t, err)
+	require.True(t, errors.Is(err, context.DeadlineExceeded))
+}
+
+func TestBlocking(t *testing.T) {
+	m := New()
+
+	m.Set("foo", "bar")
+
+	go func() {
+		time.Sleep(100 * time.Millisecond)
+		m.Set("bar", "baz")
+		time.Sleep(50 * time.Millisecond)
+		m.Set("baz", "abc")
+	}()
+
+	ctx := context.TODO()
+	v, err := m.Get(ctx, "foo", "bar", "baz")
+	require.NoError(t, err)
+	require.Equal(t, 3, len(v))
+	require.Equal(t, "bar", v["foo"])
+	require.Equal(t, "baz", v["bar"])
+	require.Equal(t, "abc", v["baz"])
+}