if n != 10 || err != nil {
		t.Fatalf("Write returned (%v, %v), want (10, nil)", n, err)
	}

	// Use ReadFrom to read in some data.
	n2, err := w.ReadFrom(strings.NewReader("abcdef"))
	if n2 != 6 || err != nil {
		t.Fatalf("ReadFrom returned (%v, %v), want (6, nil)", n2, err)
	}
}

type emptyThenNonEmptyReader struct {
	r io.Reader
	n int
}

Examples:
</p>

<pre>
var a = [...]int{0, 1, 2, 3, 4, 5, 6, 7}
var s = make([]int, 6)
var b = make([]byte, 5)
n1 := copy(s, a[0:])            // n1 == 6, s == []int{0, 1, 2, 3, 4, 5}
n2 := copy(s, s[2:])            // n2 == 4, s == []int{2, 3, 4, 5, 4, 5}
n3 := copy(b, "Hello, World!")  // n3 == 5, b == []byte("Hello")
</pre>


<h3 id="Deletion_of_map_elements">Deletion of map elements</h3>

<p>

		wantErr:   ErrHeader,
	}, {
		inputData: padInput("1\n2\n3\n"),
		inputHdrs: map[string]string{paxGNUSparseMajor: "1", paxGNUSparseMinor: "0"},
		wantMap:   sparseDatas{{2, 3}},
	}, {
		inputData: padInput("1\n2\n"),
		inputHdrs: map[string]string{paxGNUSparseMajor: "1", paxGNUSparseMinor: "0"},
		wantErr:   io.ErrUnexpectedEOF,
	}, {
		inputData: padInput("1\n2\n\n"),

	{" ", nil},
	{"\u3000 ", nil},
	{" \u3000", nil},
	{" \t\r\n \t\t\r\r\n\n ", nil},
	{" \t\r\n x\t\t\r\r\n\n ", []byte("x")},
	{" \u2000\t\r\n x\t\t\r\r\ny\n \u3000", []byte("x\t\t\r\r\ny")},
	{"1 \t\r\n2", []byte("1 \t\r\n2")},
	{" x\x80", []byte("x\x80")},
	{" x\xc0", []byte("x\xc0")},
	{"x \xc0\xc0 ", []byte("x \xc0\xc0")},
	{"x \xc0", []byte("x \xc0")},
	{"x \xc0 ", []byte("x \xc0")},

Examples:
</p>

<pre>
var a = [...]int{0, 1, 2, 3, 4, 5, 6, 7}
var s = make([]int, 6)
var b = make([]byte, 5)
n1 := copy(s, a[0:])            // n1 == 6, s is []int{0, 1, 2, 3, 4, 5}
n2 := copy(s, s[2:])            // n2 == 4, s is []int{2, 3, 4, 5, 4, 5}
n3 := copy(b, "Hello, World!")  // n3 == 5, b is []byte("Hello")
</pre>


<h3 id="Clear">Clear</h3>

<p>