diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..2c7e10a
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module github.com/dirtbags/netshovel
+
+go 1.13
+
+require github.com/google/gopacket v1.1.18
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..aa11271
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,7 @@
+github.com/google/gopacket v1.1.18 h1:lum7VRA9kdlvBi7/v2p7/zcbkduHaCH/SVVyurs7OpY=
+github.com/google/gopacket v1.1.18/go.mod h1:UdDNZ1OO62aGYVnPhxT1U6aI7ukYtA/kB8vaU0diBUM=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190405154228-4b34438f7a67/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
diff --git a/packet.go b/packet.go
index 3c0f863..89c9dda 100644
--- a/packet.go
+++ b/packet.go
@@ -91,6 +91,9 @@ func (pkt *Packet) DescribeFields() string {
 }
 
 func center(s string, w int) string {
+	if w < 3 {
+		return "?"
+	}
 	if len(s) > w {
 		s = s[0:w-3] + "…"
 	}
@@ -100,39 +103,54 @@ func center(s string, w int) string {
 // DescribeHeader returns a multi-line string describing this packet's header structure
 func (pkt *Packet) DescribeHeader() string {
 	out := new(strings.Builder)
-	fmt.Fprintln(out, " 0                               1                            ")
-	fmt.Fprintln(out, " mo0 1 2 3 4 5 6 7 8 9 a b c d e f 0 1 2 3 4 5 6 7 8 9 a b c d e f")
+	out.WriteString(" 0                               1\n")
+	out.WriteString(" 0 1 2 3 4 5 6 7 8 9 a b c d e f 0 1 2 3 4 5 6 7 8 9 a b c d e f\n")
+	out.WriteString("+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n")
 
 	bitOffset := 0
 	for _, f := range pkt.header {
 		bits := f.bits
 		for bits > 0 {
-			if bitOffset == 0 {
-				fmt.Fprintln(out, "+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+")
-			}
-
 			linebits := bits
 			if linebits+bitOffset > 0x20 {
 				linebits = 0x20 - bitOffset
 			}
 
 			// Generate centered string
-			// TODO: right-align value, center name
-			nameval := fmt.Sprintf("%s (0x%x)", f.name, f.value)
-			fmt.Fprintf(out, "|%s", center(nameval, linebits*2-1))
+			val := fmt.Sprintf("0x%x", f.value)
+			nameval := f.name
+			if f.bits == bits {
+				out.WriteString("|")
+			} else {
+				out.WriteString(" ")
+				val = ""
+				nameval = "..."
+			}
+			out.WriteString(center(nameval, linebits*2-len(val)-2))
+			out.WriteString(val)
+			out.WriteString(" ")
 
 			bitOffset += linebits
 			bits -= linebits
-			if linebits == 0x20 {
-				fmt.Fprintln(out, "|")
+			if bitOffset == 0x20 {
+				if bits == 0 {
+					out.WriteString("|")
+				} else {
+					out.WriteString(" ")
+				}
+				out.WriteString("\n")
+				out.WriteString("+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n")
 				bitOffset = 0
 			}
 		}
 	}
 	if bitOffset > 0 {
-		fmt.Fprintln(out, "|")
+		out.WriteString("|\n")
+		for o := 0; o < bitOffset; o++ {
+			out.WriteString("+-")
+		}
+		out.WriteString("+\n")
 	}
-	fmt.Fprintln(out, "+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+")
 	return out.String()
 }
 
diff --git a/packet_test.go b/packet_test.go
new file mode 100644
index 0000000..4d2465f
--- /dev/null
+++ b/packet_test.go
@@ -0,0 +1,60 @@
+package netshovel
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/dirtbags/netshovel/gapstring"
+)
+
+// BUG(neale): The DescribeHeader test is too simplistic.
+func TestHeaders(t *testing.T) {
+	pkt := NewPacket()
+	pkt.Payload = gapstring.OfBytes([]byte{0, 1, 0, 1, 42, 0xff, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 64})
+
+	a, err := pkt.Uint16LE("le")
+	if err != nil {
+		t.Error(err)
+	}
+	if a != 0x0100 {
+		t.Error("Uint16LE", a)
+	}
+
+	b, err := pkt.Uint16BE("be")
+	if err != nil {
+		t.Error(err)
+	}
+	if b != 0x0001 {
+		t.Error("Uint16BE", b)
+	}
+
+	fnord, err := pkt.Uint8("fnord")
+	if err != nil {
+		t.Error(err)
+	}
+	if fnord != 42 {
+		t.Error("Uint8", fnord)
+	}
+
+	biggun, err := pkt.Uint32LE("biggun")
+	if err != nil {
+		t.Error(err)
+	}
+	if biggun != 0xff000001 {
+		t.Error("biggun", biggun)
+	}
+
+	bignum, err := pkt.Uint64BE("bignum")
+	if err != nil {
+		t.Error(err)
+	}
+	if bignum != 64 {
+		t.Error("bignum", bignum)
+	}
+
+	desc := pkt.DescribeHeader()
+	lines := strings.Split(desc, "\n")
+	if len(lines) != 14 {
+		t.Error(desc)
+	}
+}