}
}

type panicReader struct{ panic bool }

func (r panicReader) Read(p []byte) (int, error) {
	if r.panic {
		panic("oops")
	}
	return 0, io.EOF
}

// Make sure that an empty Buffer remains empty when
// it is "grown" before a Read that panics
func TestReadFromPanicReader(t *testing.T) {

	// First verify non-panic behaviour
	var buf Buffer
	i, err := buf.ReadFrom(panicReader{})
	if err != nil {

			bf := b[:min(int64(len(b)), dataEnd-sw.pos)]
			nf, err = sw.fw.Write(bf)
		}
		b = b[nf:]
		sw.pos += int64(nf)
		if sw.pos >= dataEnd && len(sw.sp) > 1 {
			sw.sp = sw.sp[1:] // Ensure last fragment always remains
		}
	}

	n = len(b0) - len(b)
	switch {
	case err == ErrWriteTooLong:
		return n, errMissData // Not possible; implies bug in validation logic
	case err != nil:
		return n, err

			nf, err = tryReadFull(zeroReader{}, bf)
		}
		b = b[nf:]
		sr.pos += int64(nf)
		if sr.pos >= holeEnd && len(sr.sp) > 1 {
			sr.sp = sr.sp[1:] // Ensure last fragment always remains
		}
	}

	n = len(b0) - len(b)
	switch {
	case err == io.EOF:
		return n, errMissData // Less data in dense file than sparse file
	case err != nil:
		return n, err

        assertDoesNotThrow(() -> emptyIterator.remove(), "remove() should be safe to call");

        // Verify still empty after operations
        assertFalse(emptyIterator.hasNext(), "Should remain empty after operations");
    }

      editorial revisions, annotations, elaborations, or other modifications
      represent, as a whole, an original work of authorship. For the purposes
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      separable from, or merely link (or bind by name) to the interfaces of,
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      "Contribution" shall mean any work of authorship, including

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      separable from, or merely link (or bind by name) to the interfaces of,
      the Work and Derivative Works thereof.

      "Contribution" shall mean any work of authorship, including

      editorial revisions, annotations, elaborations, or other modifications
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      of this License, Derivative Works shall not include works that remain
      separable from, or merely link (or bind by name) to the interfaces of,
      the Work and Derivative Works thereof.

      "Contribution" shall mean any work of authorship, including

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      of this License, Derivative Works shall not include works that remain
      separable from, or merely link (or bind by name) to the interfaces of,
      the Work and Derivative Works thereof.

      "Contribution" shall mean any work of authorship, including

      editorial revisions, annotations, elaborations, or other modifications
      represent, as a whole, an original work of authorship. For the purposes
      of this License, Derivative Works shall not include works that remain
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      "Contribution" shall mean any work of authorship, including

///

### Namenskollisionen vermeiden

Wir importieren das Submodul `items` direkt, anstatt nur seine Variable `router` zu importieren.

Das liegt daran, dass wir im Submodul `users` auch eine weitere Variable namens `router` haben.

Wenn wir eine nach der anderen importiert hätten, etwa:

```Python