diff --git a/gemtext/fuzz_test.go b/gemtext/fuzz_test.go
new file mode 100644
index 0000000..dce0587
--- /dev/null
+++ b/gemtext/fuzz_test.go
@@ -0,0 +1,16 @@
+package gemtext_test
+
+import (
+	"bytes"
+	"testing"
+
+	"tildegit.org/tjp/gus/gemtext"
+)
+
+func FuzzParse(f *testing.F) {
+	f.Fuzz(func(t *testing.T, input []byte) {
+		if _, err := gemtext.Parse(bytes.NewBuffer(input)); err != nil {
+			t.Errorf("Parse error: %s", err.Error())
+		}
+	})
+}
diff --git a/gemtext/parse.go b/gemtext/parse.go
index 4a8c641..7041fde 100644
--- a/gemtext/parse.go
+++ b/gemtext/parse.go
@@ -2,7 +2,6 @@ package gemtext
 
 import (
 	"bufio"
-	"bytes"
 	"io"
 )
 
@@ -22,12 +21,12 @@ func Parse(input io.Reader) (Document, error) {
 		var line Line
 
 		if inPFT && (len(raw) < 3 || raw[0] != '`' || raw[1] != '`' || raw[2] != '`') {
-				line = PreformattedTextLine{raw: raw}
+			line = PreformattedTextLine{raw: raw}
 		} else {
 			line = ParseLine(raw)
 		}
 
-		if line.Type() == LineTypePreformatToggle {
+		if line != nil && line.Type() == LineTypePreformatToggle {
 			if inPFT {
 				toggle := line.(PreformatToggleLine)
 				(&toggle).clearAlt()
@@ -48,107 +47,3 @@ func Parse(input io.Reader) (Document, error) {
 
 	return Document(lines), nil
 }
-
-// ParseLine parses a single line (including the trailing \n) into a gemtext.Line.
-func ParseLine(line []byte) Line {
-	if len(line) == 0 {
-		return nil
-	}
-
-	switch line[0] {
-	case '=':
-		if len(line) == 1 || line[1] != '>' {
-			break
-		}
-		return parseLinkLine(line)
-	case '`':
-		if len(line) < 3 || line[1] != '`' || line[2] != '`' {
-			break
-		}
-		return parsePreformatToggleLine(line)
-	case '#':
-		level := 1
-		if len(line) > 1 && line[1] == '#' {
-			level += 1
-			if len(line) > 2 && line[2] == '#' {
-				level += 1
-			}
-		}
-		return parseHeadingLine(level, line)
-	case '*':
-		if len(line) == 1 || line[1] != ' ' {
-			break
-		}
-		return parseListItemLine(line)
-	case '>':
-		return parseQuoteLine(line)
-	}
-
-	return TextLine{raw: line}
-}
-
-func parseLinkLine(raw []byte) LinkLine {
-	line := LinkLine{raw: raw}
-
-	// move past =>[<whitespace>]
-	raw = bytes.TrimLeft(raw[2:], " \t")
-
-	// find the next space or tab
-	spIdx := bytes.IndexByte(raw, ' ')
-	tbIdx := bytes.IndexByte(raw, '\t')
-	idx := spIdx
-	if idx == -1 {
-		idx = tbIdx
-	}
-	if tbIdx >= 0 && tbIdx < idx {
-		idx = tbIdx
-	}
-
-	if idx < 0 {
-		line.URL = bytes.TrimRight(raw, "\r\n")
-		return line
-	}
-
-	line.URL = raw[:idx]
-	raw = raw[idx+1:]
-
-	label := bytes.TrimRight(bytes.TrimLeft(raw, " \t"), "\r\n")
-	if len(label) > 0 {
-		line.Label = label
-	}
-
-	return line
-}
-
-func parsePreformatToggleLine(raw []byte) PreformatToggleLine {
-	line := PreformatToggleLine{raw: raw}
-
-	raw = bytes.TrimRight(raw[3:], "\r\n")
-	if len(raw) > 0 {
-		line.AltText = raw
-	}
-
-	return line
-}
-
-func parseHeadingLine(level int, raw []byte) HeadingLine {
-	return HeadingLine{
-		raw:      raw,
-		lineType: LineTypeHeading1 - 1 + LineType(level),
-		Body:     bytes.TrimRight(bytes.TrimLeft(raw[level:], " \t"), "\r\n"),
-	}
-}
-
-func parseListItemLine(raw []byte) ListItemLine {
-	return ListItemLine{
-		raw:  raw,
-		Body: bytes.TrimRight(raw[2:], "\r\n"),
-	}
-}
-
-func parseQuoteLine(raw []byte) QuoteLine {
-	return QuoteLine{
-		raw:  raw,
-		Body: bytes.TrimRight(raw[1:], "\r\n"),
-	}
-}
diff --git a/gemtext/parse_line.go b/gemtext/parse_line.go
new file mode 100644
index 0000000..39187a8
--- /dev/null
+++ b/gemtext/parse_line.go
@@ -0,0 +1,107 @@
+package gemtext
+
+import "bytes"
+
+// ParseLine parses a single line (including the trailing \n) into a gemtext.Line.
+func ParseLine(line []byte) Line {
+	if len(line) == 0 {
+		return nil
+	}
+
+	switch line[0] {
+	case '=':
+		if len(line) == 1 || line[1] != '>' {
+			break
+		}
+		return parseLinkLine(line)
+	case '`':
+		if len(line) < 3 || line[1] != '`' || line[2] != '`' {
+			break
+		}
+		return parsePreformatToggleLine(line)
+	case '#':
+		level := 1
+		if len(line) > 1 && line[1] == '#' {
+			level += 1
+			if len(line) > 2 && line[2] == '#' {
+				level += 1
+			}
+		}
+		return parseHeadingLine(level, line)
+	case '*':
+		if len(line) == 1 || line[1] != ' ' {
+			break
+		}
+		return parseListItemLine(line)
+	case '>':
+		return parseQuoteLine(line)
+	}
+
+	return TextLine{raw: line}
+}
+
+func parseLinkLine(raw []byte) LinkLine {
+	line := LinkLine{raw: raw}
+
+	// move past =>[<whitespace>]
+	raw = bytes.TrimLeft(raw[2:], " \t")
+
+	// find the next space or tab
+	spIdx := bytes.IndexByte(raw, ' ')
+	tbIdx := bytes.IndexByte(raw, '\t')
+	idx := spIdx
+	if idx == -1 {
+		idx = tbIdx
+	}
+	if tbIdx >= 0 && tbIdx < idx {
+		idx = tbIdx
+	}
+
+	if idx < 0 {
+		line.url = bytes.TrimRight(raw, "\r\n")
+		return line
+	}
+
+	line.url = raw[:idx]
+	raw = raw[idx+1:]
+
+	label := bytes.TrimRight(bytes.TrimLeft(raw, " \t"), "\r\n")
+	if len(label) > 0 {
+		line.label = label
+	}
+
+	return line
+}
+
+func parsePreformatToggleLine(raw []byte) PreformatToggleLine {
+	line := PreformatToggleLine{raw: raw}
+
+	raw = bytes.TrimRight(raw[3:], "\r\n")
+	if len(raw) > 0 {
+		line.altText = raw
+	}
+
+	return line
+}
+
+func parseHeadingLine(level int, raw []byte) HeadingLine {
+	return HeadingLine{
+		raw:      raw,
+		lineType: LineTypeHeading1 - 1 + LineType(level),
+		body:     bytes.TrimRight(bytes.TrimLeft(raw[level:], " \t"), "\r\n"),
+	}
+}
+
+func parseListItemLine(raw []byte) ListItemLine {
+	return ListItemLine{
+		raw:  raw,
+		body: bytes.TrimRight(raw[2:], "\r\n"),
+	}
+}
+
+func parseQuoteLine(raw []byte) QuoteLine {
+	return QuoteLine{
+		raw:  raw,
+		body: bytes.TrimRight(raw[1:], "\r\n"),
+	}
+}
diff --git a/gemtext/parse_line_test.go b/gemtext/parse_line_test.go
index 64c1bc7..0953103 100644
--- a/gemtext/parse_line_test.go
+++ b/gemtext/parse_line_test.go
@@ -46,12 +46,12 @@ func TestParseLinkLine(t *testing.T) {
 				t.Fatalf("expected a LinkLine, got %T", line)
 			}
 
-			if string(link.URL) != test.url {
-				t.Errorf("expected url %q, got %q", test.url, string(link.URL))
+			if link.URL() != test.url {
+				t.Errorf("expected url %q, got %q", test.url, link.URL())
 			}
 
-			if string(link.Label) != test.label {
-				t.Errorf("expected label %q, got %q", test.label, string(link.Label))
+			if link.Label() != test.label {
+				t.Errorf("expected label %q, got %q", test.label, link.Label())
 			}
 		})
 	}
@@ -93,8 +93,8 @@ func TestParsePreformatToggleLine(t *testing.T) {
 				t.Fatalf("expected a PreformatToggleLine, got %T", line)
 			}
 
-			if string(toggle.AltText) != test.altText {
-				t.Errorf("expected alt-text %q, got %q", test.altText, string(toggle.AltText))
+			if toggle.AltText() != test.altText {
+				t.Errorf("expected alt-text %q, got %q", test.altText, toggle.AltText())
 			}
 		})
 	}
@@ -147,8 +147,8 @@ func TestParseHeadingLine(t *testing.T) {
 				t.Fatalf("expected HeadingLine, got a %T", line)
 			}
 
-			if string(hdg.Body) != test.body {
-				t.Errorf("expected body %q, got %q", test.body, string(hdg.Body))
+			if hdg.Body() != test.body {
+				t.Errorf("expected body %q, got %q", test.body, hdg.Body())
 			}
 		})
 	}
@@ -188,8 +188,8 @@ func TestParseListItemLine(t *testing.T) {
 				t.Fatalf("expected ListItemLine, got a %T", line)
 			}
 
-			if string(li.Body) != test.body {
-				t.Errorf("expected body %q, got %q", test.body, string(li.Body))
+			if li.Body() != test.body {
+				t.Errorf("expected body %q, got %q", test.body, li.Body())
 			}
 		})
 	}
@@ -233,8 +233,8 @@ func TestParseQuoteLine(t *testing.T) {
 				t.Fatalf("expected QuoteLine , got a %T", line)
 			}
 
-			if string(qu.Body) != test.body {
-				t.Errorf("expected body %q, got %q", test.body, string(qu.Body))
+			if qu.Body() != test.body {
+				t.Errorf("expected body %q, got %q", test.body, qu.Body())
 			}
 		})
 	}
diff --git a/gemtext/parse_test.go b/gemtext/parse_test.go
new file mode 100644
index 0000000..bda5310
--- /dev/null
+++ b/gemtext/parse_test.go
@@ -0,0 +1,104 @@
+package gemtext_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"tildegit.org/tjp/gus/gemtext"
+)
+
+func TestParse(t *testing.T) {
+	docBytes := []byte(`
+# top-level header line
+
+## subtitle
+
+This is some non-blank regular text.
+
+* an
+* unordered
+* list
+
+=> gemini://google.com/ as if
+
+> this is a quote
+> -tjp
+
+`[1:] + "```pre-formatted code\ndoc := gemtext.Parse(req.Body)\n```ignored closing alt-text\n")
+
+	assertEmptyLine := func(t *testing.T, line gemtext.Line) {
+		assert.Equal(t, gemtext.LineTypeText, line.Type())
+		assert.Equal(t, "\n", string(line.Raw()))
+	}
+
+	doc, err := gemtext.Parse(bytes.NewBuffer(docBytes))
+	require.Nil(t, err)
+
+	require.Equal(t, 18, len(doc))
+
+	assert.Equal(t, gemtext.LineTypeHeading1, doc[0].Type())
+	assert.Equal(t, "# top-level header line\n", string(doc[0].Raw()))
+	assert.Equal(t, "top-level header line", doc[0].(gemtext.HeadingLine).Body())
+
+	assertEmptyLine(t, doc[1])
+
+	assert.Equal(t, gemtext.LineTypeHeading2, doc[2].Type())
+	assert.Equal(t, "## subtitle\n", string(doc[2].Raw()))
+	assert.Equal(t, "subtitle", doc[2].(gemtext.HeadingLine).Body())
+
+	assertEmptyLine(t, doc[3])
+
+	assert.Equal(t, gemtext.LineTypeText, doc[4].Type())
+	assert.Equal(t, "This is some non-blank regular text.\n", string(doc[4].Raw()))
+
+	assertEmptyLine(t, doc[5])
+
+	assert.Equal(t, gemtext.LineTypeListItem, doc[6].Type())
+	assert.Equal(t, "an", doc[6].(gemtext.ListItemLine).Body())
+
+	assert.Equal(t, gemtext.LineTypeListItem, doc[7].Type())
+	assert.Equal(t, "unordered", doc[7].(gemtext.ListItemLine).Body())
+
+	assert.Equal(t, gemtext.LineTypeListItem, doc[8].Type())
+	assert.Equal(t, "list", doc[8].(gemtext.ListItemLine).Body())
+
+	assertEmptyLine(t, doc[9])
+
+	assert.Equal(t, gemtext.LineTypeLink, doc[10].Type())
+	assert.Equal(t, "=> gemini://google.com/ as if\n", string(doc[10].Raw()))
+	assert.Equal(t, "gemini://google.com/", doc[10].(gemtext.LinkLine).URL())
+	assert.Equal(t, "as if", doc[10].(gemtext.LinkLine).Label())
+
+	assertEmptyLine(t, doc[11])
+
+	assert.Equal(t, gemtext.LineTypeQuote, doc[12].Type())
+	assert.Equal(t, "> this is a quote\n", string(doc[12].Raw()))
+	assert.Equal(t, " this is a quote", doc[12].(gemtext.QuoteLine).Body())
+
+	assert.Equal(t, gemtext.LineTypeQuote, doc[13].Type())
+	assert.Equal(t, "> -tjp\n", string(doc[13].Raw()))
+	assert.Equal(t, " -tjp", doc[13].(gemtext.QuoteLine).Body())
+
+	assertEmptyLine(t, doc[14])
+
+	assert.Equal(t, gemtext.LineTypePreformatToggle, doc[15].Type())
+	assert.Equal(t, "```pre-formatted code\n", string(doc[15].Raw()))
+	assert.Equal(t, "pre-formatted code", doc[15].(gemtext.PreformatToggleLine).AltText())
+
+	assert.Equal(t, gemtext.LineTypePreformattedText, doc[16].Type())
+	assert.Equal(t, "doc := gemtext.Parse(req.Body)\n", string(doc[16].Raw()))
+
+	assert.Equal(t, gemtext.LineTypePreformatToggle, doc[17].Type())
+	assert.Equal(t, "```ignored closing alt-text\n", string(doc[17].Raw()))
+	assert.Equal(t, "", doc[17].(gemtext.PreformatToggleLine).AltText())
+
+	// ensure we can rebuild the original doc from all the line.Raw()s
+	buf := &bytes.Buffer{}
+	for _, line := range doc {
+		_, _ = buf.Write(line.Raw())
+	}
+	assert.Equal(t, string(docBytes), buf.String())
+}
diff --git a/gemtext/types.go b/gemtext/types.go
index fb9352a..fefbece 100644
--- a/gemtext/types.go
+++ b/gemtext/types.go
@@ -91,39 +91,39 @@ func (tl TextLine) Raw() []byte    { return tl.raw }
 // LinkLine is a line of LineTypeLink.
 type LinkLine struct {
 	raw   []byte
-
-	// URL is the original bytes of the url portion of the line.
-	//
-	// It is not guaranteed to be a valid URL.
-	URL   []byte
-
-	// Label is the label portion of the line.
-	//
-	// If there was no label it will always be nil, never []byte{}.
-	Label []byte
+	url   []byte
+	label []byte
 }
 
 func (ll LinkLine) Type() LineType { return LineTypeLink }
 func (ll LinkLine) Raw() []byte    { return ll.raw }
 
+// URL returns the original url portion of the line.
+//
+// It is not guaranteed to be a valid URL.
+func (ll LinkLine) URL() string { return string(ll.url) }
+
+// Label returns the label portion of the line.
+func (ll LinkLine) Label() string { return string(ll.label) }
+
 // PreformatToggleLine is a preformatted text toggle line.
 type PreformatToggleLine struct {
 	raw     []byte
-
-	// AltText contains the alt-text portion of the line.
-	//
-	// It will either have len() > 0 or be nil.
-	//
-	// If the line was parsed as part of a full document by Parse(),
-	// and this is a *closing* toggle, any alt-text present will be
-	// stripped and this will be nil. If the line was parsed by
-	// ParseLine() no such correction is performed.
-	AltText []byte
+	altText []byte
 }
 
 func (tl PreformatToggleLine) Type() LineType { return LineTypePreformatToggle }
 func (tl PreformatToggleLine) Raw() []byte    { return tl.raw }
-func (tl *PreformatToggleLine) clearAlt()     { tl.AltText = nil }
+
+// AltText returns the alt-text portion of the line.
+//
+// If the line was parsed as part of a full document by Parse(),
+// and this is a *closing* toggle, any alt-text present will be
+// stripped and this will be empty. If the line was parsed by
+// ParseLine() no such correction is performed.
+func (tl PreformatToggleLine) AltText() string { return string(tl.altText) }
+
+func (tl *PreformatToggleLine) clearAlt() { tl.altText = nil }
 
 // PreformattedTextLine represents a line between two toggles.
 //
@@ -140,32 +140,35 @@ func (tl PreformattedTextLine) Raw() []byte    { return tl.raw }
 type HeadingLine struct {
 	raw      []byte
 	lineType LineType
-
-	// Body is the portion of the line with the header text.
-	Body []byte
+	body     []byte
 }
 
 func (hl HeadingLine) Type() LineType { return hl.lineType }
 func (hl HeadingLine) Raw() []byte    { return hl.raw }
 
+// Body returns the portion of the line with the header text.
+func (hl HeadingLine) Body() string { return string(hl.body) }
+
 // ListItemLine is a line of LineTypeListItem.
 type ListItemLine struct {
 	raw  []byte
-
-	// Body is the text of the list item.
-	Body []byte
+	body []byte
 }
 
 func (li ListItemLine) Type() LineType { return LineTypeListItem }
 func (li ListItemLine) Raw() []byte    { return li.raw }
 
+// Body returns the text of the list item.
+func (li ListItemLine) Body() string { return string(li.body) }
+
 // QuoteLine is a line of LineTypeQuote.
 type QuoteLine struct {
-	raw []byte
-
-	// Body is the text of the quote.
-	Body []byte
+	raw  []byte
+	body []byte
 }
 
 func (ql QuoteLine) Type() LineType { return LineTypeQuote }
 func (ql QuoteLine) Raw() []byte    { return ql.raw }
+
+// Body returns the text of the quote.
+func (ql QuoteLine) Body() string { return string(ql.body) }
diff --git a/go.mod b/go.mod
index 7af8e8d..900e959 100644
--- a/go.mod
+++ b/go.mod
@@ -2,6 +2,14 @@ module tildegit.org/tjp/gus
 
 go 1.19
 
-require github.com/go-kit/log v0.2.1
+require (
+	github.com/go-kit/log v0.2.1
+	github.com/stretchr/testify v1.8.1
+)
 
-require github.com/go-logfmt/logfmt v0.5.1 // indirect
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-logfmt/logfmt v0.5.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
diff --git a/go.sum b/go.sum
index fa964aa..d766032 100644
--- a/go.sum
+++ b/go.sum
@@ -1,4 +1,21 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-kit/log v0.2.1 h1:MRVx0/zhvdseW+Gza6N9rVzU/IVzaeE1SFI4raAhmBU=
 github.com/go-kit/log v0.2.1/go.mod h1:NwTd00d/i8cPZ3xOwwiv2PO5MOcx78fFErGNcVmBjv0=
 github.com/go-logfmt/logfmt v0.5.1 h1:otpy5pqBCBZ1ng9RQ0dPu4PN7ba75Y/aA+UpowDyNVA=
 github.com/go-logfmt/logfmt v0.5.1/go.mod h1:WYhtIu8zTZfxdn5+rREduYbwxfcBr/Vr6KEVveWlfTs=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=