CC-1731: Fix Redis #xu1

internal/resp/decoder/decode_array.go

@@ -31,7 +31,11 @@ func decodeArray(reader *bytes.Reader) (resp_value.Value, error) {
 		}
 	}
 
-	if length < 0 {
+	if length == -1 {
+		return resp_value.NewNilValue(), nil
+	}
+
+	if length < -1 {
 		// Ensure error points to the correct byte
 		reader.Seek(int64(offsetBeforeLength), io.SeekStart)
 

internal/resp/value/value.go

@@ -125,3 +125,19 @@ func (v *Value) FormattedString() string {
 
 	return ""
 }
+
+func (v Value) ToSerializable() interface{} {
+	switch v.Type {
+	case BULK_STRING:
+		return v.String()
+	case ARRAY:
+		arr := v.Array()
+		result := make([]interface{}, len(arr))
+		for i, elem := range arr {
+			result[i] = elem.ToSerializable()
+		}
+		return result
+	default:
+		return v.String()
+	}
+}

internal/resp_assertions/xread_response_assertion.go

@@ -0,0 +1,82 @@
+package resp_assertions
+
+import (
+	"encoding/json"
+	"fmt"
+
+	resp_value "github.com/codecrafters-io/redis-tester/internal/resp/value"
+)
+
+type StreamEntry struct {
+	Id              string
+	FieldValuePairs [][]string
+}
+
+type StreamResponse struct {
+	Key     string
+	Entries []StreamEntry
+}
+
+type XReadResponseAssertion struct {
+	ExpectedStreamResponses []StreamResponse
+}
+
+func NewXReadResponseAssertion(expectedValue []StreamResponse) RESPAssertion {
+	return XReadResponseAssertion{ExpectedStreamResponses: expectedValue}
+}
+
+func (a XReadResponseAssertion) Run(value resp_value.Value) error {
+	if value.Type != resp_value.ARRAY {
+		return fmt.Errorf("Expected array, got %s", value.Type)
+	}
+
+	expected := a.buildExpected().ToSerializable()
+	actual := value.ToSerializable()
+
+	expectedJSON, err := json.MarshalIndent(expected, "", "  ")
+	if err != nil {
+		return fmt.Errorf("failed to marshal expected value: %w", err)
+	}
+	actualJSON, err := json.MarshalIndent(actual, "", "  ")
+	if err != nil {
+		return fmt.Errorf("failed to marshal actual value: %w", err)
+	}
+
+	if string(expectedJSON) != string(actualJSON) {
+		return fmt.Errorf("XREAD response mismatch:\nExpected:\n%s\nGot:\n%s", expectedJSON, actualJSON)
+	}
+
+	return nil
+}
+
+func (a XReadResponseAssertion) buildExpected() resp_value.Value {
+	streams := make([]resp_value.Value, len(a.ExpectedStreamResponses))
+	for i, stream := range a.ExpectedStreamResponses {
+		streams[i] = stream.toRESPValue()
+	}
+	return resp_value.NewArrayValue(streams)
+}
+
+func (s StreamResponse) toRESPValue() resp_value.Value {
+	entries := make([]resp_value.Value, len(s.Entries))
+	for i, entry := range s.Entries {
+		entries[i] = entry.toRESPValue()
+	}
+	return resp_value.NewArrayValue([]resp_value.Value{
+		resp_value.NewBulkStringValue(s.Key),
+		resp_value.NewArrayValue(entries),
+	})
+}
+
+func (e StreamEntry) toRESPValue() resp_value.Value {
+	var fieldValues []resp_value.Value
+	for _, pair := range e.FieldValuePairs {
+		for _, v := range pair {
+			fieldValues = append(fieldValues, resp_value.NewBulkStringValue(v))
+		}
+	}
+	return resp_value.NewArrayValue([]resp_value.Value{
+		resp_value.NewBulkStringValue(e.Id),
+		resp_value.NewArrayValue(fieldValues),
+	})
+}