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package chord
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import (
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	"context"
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	"testing"
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	"time"
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	"github.com/stretchr/testify/require"
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)
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type retryTestNode struct {
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	VNode
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	get func(context.Context, []byte) ([]byte, error)
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}
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func (n *retryTestNode) Get(ctx context.Context, key []byte) ([]byte, error) {
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	return n.get(ctx, key)
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}
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func TestRetryKVPreservesAttemptsValuesAndErrors(t *testing.T) {
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	for _, tc := range []struct {
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		name    string
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		results []error
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		wantErr error
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	}{
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		{name: "retry stale ownership", results: []error{ErrKVStaleOwnership, nil}},
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		{name: "stop on conflict", results: []error{ErrKVSimpleConflict}, wantErr: ErrKVSimpleConflict},
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		{name: "return final error", results: []error{ErrKVStaleOwnership, ErrKVPendingTransfer, ErrKVPendingTransfer}, wantErr: ErrKVPendingTransfer},
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	} {
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		t.Run(tc.name, func(t *testing.T) {
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			calls := 0
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			node := &retryTestNode{get: func(ctx context.Context, key []byte) ([]byte, error) {
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				require.Equal(t, []byte("key"), key)
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				require.NoError(t, ctx.Err())
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				if calls >= len(tc.results) {
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					t.Fatal("retried after the expected final attempt")
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				}
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				err := tc.results[calls]
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				calls++
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				return []byte{}, err
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			}}
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			value, err := WrapRetryKV(node, time.Nanosecond, 3).Get(t.Context(), []byte("key"))
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			require.Equal(t, tc.wantErr, err, "errors must remain directly comparable")
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			require.Equal(t, len(tc.results), calls)
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			if err == nil {
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				require.NotNil(t, value, "successful empty values must stay distinct from missing values")
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				require.Empty(t, value)
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			}
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		})
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	}
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}
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func TestRetryKVCancellationStopsBackoff(t *testing.T) {
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	ctx, cancel := context.WithCancel(t.Context())
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	defer cancel()
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	calls := 0
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	node := &retryTestNode{get: func(context.Context, []byte) ([]byte, error) {
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		calls++
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		cancel()
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		return nil, ErrKVStaleOwnership
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	}}
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	_, err := WrapRetryKV(node, time.Hour, 3).Get(ctx, []byte("key"))
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	require.ErrorIs(t, err, context.Canceled)
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	require.Equal(t, 1, calls)
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}