diff --git a/dbg/BUILD.bazel b/dbg/BUILD.bazel
index c55279b..113b53e 100644
--- a/dbg/BUILD.bazel
+++ b/dbg/BUILD.bazel
@@ -9,11 +9,11 @@ go_library(
 
 go_test(
     name = "dbg_test",
+    size = "small",
     srcs = ["dbg_test.go"],
     embed = [":dbg"],
     deps = [
         "//testio",
         "@com_github_stretchr_testify//require",
     ],
-    size = "small",
 )
diff --git a/lib/BUILD.bazel b/lib/BUILD.bazel
index 1ce1a39..3497e70 100644
--- a/lib/BUILD.bazel
+++ b/lib/BUILD.bazel
@@ -110,8 +110,8 @@ go_library(
 
 go_test(
     name = "lib_test",
+    size = "small",
     srcs = ["lib_test.go"],
     embed = [":lib"],
     deps = ["//assert"],
-    size = "small",
 )
diff --git a/logging/BUILD.bazel b/logging/BUILD.bazel
index af733f8..af16f4b 100644
--- a/logging/BUILD.bazel
+++ b/logging/BUILD.bazel
@@ -15,10 +15,10 @@ go_library(
 
 go_test(
     name = "logging_test",
+    size = "small",
     srcs = [
         "example_test.go",
         "log_test.go",
     ],
     embed = [":logging"],
-    size = "small",
 )
diff --git a/mwc/BUILD.bazel b/mwc/BUILD.bazel
index b5fe655..a50e044 100644
--- a/mwc/BUILD.bazel
+++ b/mwc/BUILD.bazel
@@ -9,11 +9,11 @@ go_library(
 
 go_test(
     name = "mwc_test",
+    size = "small",
     srcs = ["mwc_test.go"],
     embed = [":mwc"],
     deps = [
         "//assert",
         "//testio",
     ],
-    size = "small",
 )
diff --git a/rand/BUILD.bazel b/rand/BUILD.bazel
index 159728b..1115ae9 100644
--- a/rand/BUILD.bazel
+++ b/rand/BUILD.bazel
@@ -9,7 +9,7 @@ go_library(
 
 go_test(
     name = "rand_test",
+    size = "small",
     srcs = ["rand_test.go"],
     embed = [":rand"],
-    size = "small",
 )
diff --git a/sbuf/BUILD.bazel b/sbuf/BUILD.bazel
index f605a2c..141d0c8 100644
--- a/sbuf/BUILD.bazel
+++ b/sbuf/BUILD.bazel
@@ -9,8 +9,8 @@ go_library(
 
 go_test(
     name = "sbuf_test",
+    size = "small",
     srcs = ["sbuf_test.go"],
     embed = [":sbuf"],
     deps = ["@org_golang_x_crypto//nacl/box"],
-    size = "small",
 )
diff --git a/seekbuf/BUILD.bazel b/seekbuf/BUILD.bazel
index cd5d55f..925a0da 100644
--- a/seekbuf/BUILD.bazel
+++ b/seekbuf/BUILD.bazel
@@ -1,4 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "seekbuf",
@@ -6,3 +6,11 @@ go_library(
     importpath = "git.wntrmute.dev/kyle/goutils/seekbuf",
     visibility = ["//visibility:public"],
 )
+
+go_test(
+    name = "seekbuf_test",
+    srcs = ["seekbuf_test.go"],
+    embed = [":seekbuf"],
+    deps = ["//assert"],
+    size = "small"
+)
diff --git a/seekbuf/seekbuf.go b/seekbuf/seekbuf.go
index be10e25..253f988 100644
--- a/seekbuf/seekbuf.go
+++ b/seekbuf/seekbuf.go
@@ -1,3 +1,4 @@
+// seekbuf implements a read-seekable buffer.
 package seekbuf
 
 import "io"
@@ -40,7 +41,7 @@ func (b *Buffer) Seek(pos int) {
 
 // Rewind resets the read pointer to 0.
 func (b *Buffer) Rewind() {
-	b.pos = 0
+	b.Seek(0)
 }
 
 // Close clears all the data out of the buffer and sets the read position to 0.
@@ -49,3 +50,8 @@ func (b *Buffer) Close() error {
 	b.pos = 0
 	return nil
 }
+
+// Len returns the length of data remaining to be read.
+func (b *Buffer) Len() int {
+	return len(b.data[b.pos:])
+}
diff --git a/testio/BUILD.bazel b/testio/BUILD.bazel
index ce53aec..64167e7 100644
--- a/testio/BUILD.bazel
+++ b/testio/BUILD.bazel
@@ -9,7 +9,7 @@ go_library(
 
 go_test(
     name = "testio_test",
+    size = "small",
     srcs = ["testio_test.go"],
     embed = [":testio"],
-    size = "small",
 )