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package entropy
import (
"bytes"
"io"
"strings"
"testing"
)
func TestHybridReaderMixesBaseAndExternal(t *testing.T) {
base := strings.NewReader(strings.Repeat("a", 4096))
external := strings.NewReader(strings.Repeat("b", 4096))
reader, err := NewHybridReader(base, external, HybridOptions{})
if err != nil {
t.Fatalf("NewHybridReader returned error: %v", err)
}
out := make([]byte, 128)
if _, err := io.ReadFull(reader, out); err != nil {
t.Fatalf("Read returned error: %v", err)
}
if bytes.Equal(out, bytes.Repeat([]byte("a"), len(out))) {
t.Fatalf("hybrid output matched raw base reader")
}
if reader.Degraded() {
t.Fatalf("hybrid reader degraded with enough external bytes")
}
}
func TestHybridReaderDegradesToBaseWhenExternalFails(t *testing.T) {
base := strings.NewReader(strings.Repeat("x", 4096))
external := strings.NewReader("")
reader, err := NewHybridReader(base, external, HybridOptions{})
if err != nil {
t.Fatalf("NewHybridReader returned error: %v", err)
}
out := make([]byte, 32)
if _, err := io.ReadFull(reader, out); err != nil {
t.Fatalf("Read returned error: %v", err)
}
if !bytes.Equal(out, bytes.Repeat([]byte("x"), len(out))) {
t.Fatalf("degraded output should come from base reader")
}
if !reader.Degraded() {
t.Fatalf("hybrid reader should report degraded state")
}
if reader.DegradeError() == nil {
t.Fatalf("hybrid reader should keep the external source error")
}
}
func TestHybridReaderBuffersSmallReads(t *testing.T) {
base := strings.NewReader(strings.Repeat("a", blockSize))
external := strings.NewReader(strings.Repeat("b", blockSize))
reader, err := NewHybridReader(base, external, HybridOptions{})
if err != nil {
t.Fatalf("NewHybridReader returned error: %v", err)
}
var one [1]byte
for i := 0; i < blockSize; i++ {
if _, err := io.ReadFull(reader, one[:]); err != nil {
t.Fatalf("Read %d returned error: %v", i, err)
}
}
if reader.Degraded() {
t.Fatalf("small reads should reuse one mixed block before reading external again")
}
}
func TestHybridReaderRequiresExternalWhenConfigured(t *testing.T) {
base := strings.NewReader(strings.Repeat("x", 4096))
external := strings.NewReader("")
reader, err := NewHybridReader(base, external, HybridOptions{RequireExternal: true})
if err != nil {
t.Fatalf("NewHybridReader returned error: %v", err)
}
out := make([]byte, 1)
if _, err := io.ReadFull(reader, out); err == nil {
t.Fatalf("Read returned nil error with required external entropy")
}
}
func TestNewHybridReaderRejectsMissingExternalSource(t *testing.T) {
if _, err := NewHybridReader(strings.NewReader("base"), nil, HybridOptions{}); err != ErrExternalEntropyRequired {
t.Fatalf("NewHybridReader error = %v, want %v", err, ErrExternalEntropyRequired)
}
}
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