diff --git a/embedmd/command_test.go b/embedmd/command_test.go
index da978cc..630aa76 100644
--- a/embedmd/command_test.go
+++ b/embedmd/command_test.go
@@ -13,7 +13,11 @@
 
 package embedmd
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/campoy/embedmd/internal/testutil"
+)
 
 func TestParseCommand(t *testing.T) {
 	tc := []struct {
@@ -24,10 +28,10 @@ func TestParseCommand(t *testing.T) {
 	}{
 		{name: "start to end",
 			in:  "(code.go /start/ /end/)",
-			cmd: command{path: "code.go", lang: "go", start: ptr("/start/"), end: ptr("/end/")}},
+			cmd: command{path: "code.go", lang: "go", start: testutil.Ptr("/start/"), end: testutil.Ptr("/end/")}},
 		{name: "only start",
 			in:  "(code.go     /start/)",
-			cmd: command{path: "code.go", lang: "go", start: ptr("/start/")}},
+			cmd: command{path: "code.go", lang: "go", start: testutil.Ptr("/start/")}},
 		{name: "empty list",
 			in:  "()",
 			err: "missing file name"},
@@ -54,10 +58,10 @@ func TestParseCommand(t *testing.T) {
 			cmd: command{path: "test.md", lang: "markdown"}},
 		{name: "multi-line comments",
 			in:  `(doc.go /\/\*/ /\*\//)`,
-			cmd: command{path: "doc.go", lang: "go", start: ptr(`/\/\*/`), end: ptr(`/\*\//`)}},
+			cmd: command{path: "doc.go", lang: "go", start: testutil.Ptr(`/\/\*/`), end: testutil.Ptr(`/\*\//`)}},
 		{name: "using $ as end",
 			in:  "(foo.go /start/ $)",
-			cmd: command{path: "foo.go", lang: "go", start: ptr("/start/"), end: ptr("$")}},
+			cmd: command{path: "foo.go", lang: "go", start: testutil.Ptr("/start/"), end: testutil.Ptr("$")}},
 		{name: "extra arguments",
 			in: "(foo.go /start/ $ extra)", err: "too many arguments"},
 		{name: "file name with directories",
@@ -74,7 +78,7 @@ func TestParseCommand(t *testing.T) {
 	for _, tt := range tc {
 		t.Run(tt.name, func(t *testing.T) {
 			cmd, err := parseCommand(tt.in)
-			if !eqErr(t, tt.name, err, tt.err) {
+			if !testutil.EqErr(t, tt.name, err, tt.err) {
 				return
 			}
 
@@ -85,43 +89,12 @@ func TestParseCommand(t *testing.T) {
 			if want.lang != got.lang {
 				t.Errorf("case [%s]: expected language %q; got %q", tt.name, want.lang, got.lang)
 			}
-			if !eqPtr(want.start, got.start) {
-				t.Errorf("case [%s]: expected start %v; got %v", tt.name, str(want.start), str(got.start))
+			if !testutil.EqPtr(want.start, got.start) {
+				t.Errorf("case [%s]: expected start %v; got %v", tt.name, testutil.Str(want.start), testutil.Str(got.start))
 			}
-			if !eqPtr(want.end, got.end) {
-				t.Errorf("case [%s]: expected end %v; got %v", tt.name, str(want.end), str(got.end))
+			if !testutil.EqPtr(want.end, got.end) {
+				t.Errorf("case [%s]: expected end %v; got %v", tt.name, testutil.Str(want.end), testutil.Str(got.end))
 			}
 		})
 	}
 }
-
-func ptr(s string) *string { return &s }
-
-func str(s *string) string {
-	if s == nil {
-		return "<nil>"
-	}
-	return *s
-}
-
-func eqPtr(a, b *string) bool {
-	if a == nil || b == nil {
-		return a == b
-	}
-	return *a == *b
-}
-
-func eqErr(t *testing.T, id string, err error, msg string) bool {
-	t.Helper()
-	if err == nil && msg == "" {
-		return true
-	}
-	if err == nil && msg != "" {
-		t.Errorf("case [%s]: expected error message %q; but got nothing", id, msg)
-		return false
-	}
-	if err != nil && msg != err.Error() {
-		t.Errorf("case [%s]: expected error message %q; but got %q", id, msg, err)
-	}
-	return false
-}
diff --git a/embedmd/embedmd.go b/embedmd/embedmd.go
index c59cc2a..aed9eea 100644
--- a/embedmd/embedmd.go
+++ b/embedmd/embedmd.go
@@ -16,7 +16,7 @@
 //
 // The format of an embedmd command is:
 //
-//     [embedmd]:# (pathOrURL language /start regexp/ /end regexp/)
+//	[embedmd]:# (pathOrURL language /start regexp/ /end regexp/)
 //
 // The embedded code will be extracted from the file at pathOrURL,
 // which can either be a relative path to a file in the local file
@@ -29,27 +29,26 @@
 // Omitting the the second regular expression will embed only the piece of
 // text that matches /regexp/:
 //
-//     [embedmd]:# (pathOrURL language /regexp/)
+//	[embedmd]:# (pathOrURL language /regexp/)
 //
 // To embed the whole line matching a regular expression you can use:
 //
-//     [embedmd]:# (pathOrURL language /.*regexp.*\n/)
+//	[embedmd]:# (pathOrURL language /.*regexp.*\n/)
 //
 // If you want to embed from a point to the end you should use:
 //
-//     [embedmd]:# (pathOrURL language /start regexp/ $)
+//	[embedmd]:# (pathOrURL language /start regexp/ $)
 //
 // Finally you can embed a whole file by omitting both regular expressions:
 //
-//     [embedmd]:# (pathOrURL language)
+//	[embedmd]:# (pathOrURL language)
 //
 // You can ommit the language in any of the previous commands, and the extension
 // of the file will be used for the snippet syntax highlighting. Note that while
 // this works Go files, since the file extension .go matches the name of the language
 // go, this will fail with other files like .md whose language name is markdown.
 //
-//     [embedmd]:# (file.ext)
-//
+//	[embedmd]:# (file.ext)
 package embedmd
 
 import (
diff --git a/embedmd/embedmd_test.go b/embedmd/embedmd_test.go
index 8c113c8..dba20d1 100644
--- a/embedmd/embedmd_test.go
+++ b/embedmd/embedmd_test.go
@@ -21,6 +21,8 @@ import (
 	"path/filepath"
 	"strings"
 	"testing"
+
+	"github.com/campoy/embedmd/internal/testutil"
 )
 
 const content = `
@@ -43,37 +45,37 @@ func TestExtract(t *testing.T) {
 		{name: "no limits",
 			out: string(content)},
 		{name: "only one line",
-			start: ptr("/func main.*\n/"), out: "func main() {\n"},
+			start: testutil.Ptr("/func main.*\n/"), out: "func main() {\n"},
 		{name: "from package to end",
-			start: ptr("/package main/"), end: ptr("$"), out: string(content[1:])},
+			start: testutil.Ptr("/package main/"), end: testutil.Ptr("$"), out: string(content[1:])},
 		{name: "not matching",
-			start: ptr("/gopher/"), err: "could not match \"/gopher/\""},
+			start: testutil.Ptr("/gopher/"), err: "could not match \"/gopher/\""},
 		{name: "part of a line",
-			start: ptr("/fmt.P/"), end: ptr("/hello/"), out: "fmt.Println(\"hello"},
+			start: testutil.Ptr("/fmt.P/"), end: testutil.Ptr("/hello/"), out: "fmt.Println(\"hello"},
 		{name: "function call",
-			start: ptr("/fmt\\.[^()]*/"), out: "fmt.Println"},
+			start: testutil.Ptr("/fmt\\.[^()]*/"), out: "fmt.Println"},
 		{name: "from fmt to end of line",
-			start: ptr("/fmt.P.*\n/"), out: "fmt.Println(\"hello, test\")\n"},
+			start: testutil.Ptr("/fmt.P.*\n/"), out: "fmt.Println(\"hello, test\")\n"},
 		{name: "from func to end of next line",
-			start: ptr("/func/"), end: ptr("/Println.*\n/"), out: "func main() {\n        fmt.Println(\"hello, test\")\n"},
+			start: testutil.Ptr("/func/"), end: testutil.Ptr("/Println.*\n/"), out: "func main() {\n        fmt.Println(\"hello, test\")\n"},
 		{name: "from func to }",
-			start: ptr("/func main/"), end: ptr("/}/"), out: "func main() {\n        fmt.Println(\"hello, test\")\n}"},
+			start: testutil.Ptr("/func main/"), end: testutil.Ptr("/}/"), out: "func main() {\n        fmt.Println(\"hello, test\")\n}"},
 
 		{name: "bad start regexp",
-			start: ptr("/(/"), err: "error parsing regexp: missing closing ): `(`"},
+			start: testutil.Ptr("/(/"), err: "error parsing regexp: missing closing ): `(`"},
 		{name: "bad regexp",
-			start: ptr("something"), err: "missing slashes (/) around \"something\""},
+			start: testutil.Ptr("something"), err: "missing slashes (/) around \"something\""},
 		{name: "bad end regexp",
-			start: ptr("/fmt.P/"), end: ptr("/)/"), err: "error parsing regexp: unexpected ): `)`"},
+			start: testutil.Ptr("/fmt.P/"), end: testutil.Ptr("/)/"), err: "error parsing regexp: unexpected ): `)`"},
 
 		{name: "start and end of line ^$",
-			start: ptr("/^func main/"), end: ptr("/}$/"), out: "func main() {\n        fmt.Println(\"hello, test\")\n}"},
+			start: testutil.Ptr("/^func main/"), end: testutil.Ptr("/}$/"), out: "func main() {\n        fmt.Println(\"hello, test\")\n}"},
 	}
 
 	for _, tt := range tc {
 		t.Run(tt.name, func(t *testing.T) {
 			b, err := extract([]byte(content), tt.start, tt.end)
-			if !eqErr(t, tt.name, err, tt.err) {
+			if !testutil.EqErr(t, tt.name, err, tt.err) {
 				return
 			}
 			if string(b) != tt.out {
@@ -107,7 +109,7 @@ func TestExtractFromFile(t *testing.T) {
 		},
 		{
 			name:  "added line break",
-			cmd:   command{path: "code.go", lang: "go", start: ptr("/fmt\\.Println/")},
+			cmd:   command{path: "code.go", lang: "go", start: testutil.Ptr("/fmt\\.Println/")},
 			files: map[string][]byte{"code.go": []byte(content)},
 			out:   "```go\nfmt.Println\n```\n",
 		},
@@ -118,7 +120,7 @@ func TestExtractFromFile(t *testing.T) {
 		},
 		{
 			name:  "unmatched regexp",
-			cmd:   command{path: "code.go", lang: "go", start: ptr("/potato/")},
+			cmd:   command{path: "code.go", lang: "go", start: testutil.Ptr("/potato/")},
 			files: map[string][]byte{"code.go": []byte(content)},
 			err:   "could not extract content from code.go: could not match \"/potato/\"",
 		},
@@ -133,7 +135,7 @@ func TestExtractFromFile(t *testing.T) {
 
 			w := new(bytes.Buffer)
 			err := e.runCommand(w, &tt.cmd)
-			if !eqErr(t, tt.name, err, tt.err) {
+			if !testutil.EqErr(t, tt.name, err, tt.err) {
 				return
 			}
 			if w.String() != tt.out {
@@ -267,7 +269,7 @@ func TestProcess(t *testing.T) {
 				opts = append(opts, WithBaseDir(tt.dir))
 			}
 			err := Process(&out, strings.NewReader(tt.in), opts...)
-			if !eqErr(t, tt.name, err, tt.err) {
+			if !testutil.EqErr(t, tt.name, err, tt.err) {
 				return
 			}
 			if tt.out != out.String() {
diff --git a/embedmd/parser_test.go b/embedmd/parser_test.go
index 51007d4..a9b26c7 100644
--- a/embedmd/parser_test.go
+++ b/embedmd/parser_test.go
@@ -19,6 +19,8 @@ import (
 	"io"
 	"strings"
 	"testing"
+
+	"github.com/campoy/embedmd/internal/testutil"
 )
 
 func TestParser(t *testing.T) {
@@ -94,7 +96,7 @@ func TestParser(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			var out bytes.Buffer
 			err := process(&out, strings.NewReader(tt.in), tt.run)
-			if !eqErr(t, tt.name, err, tt.err) {
+			if !testutil.EqErr(t, tt.name, err, tt.err) {
 				return
 			}
 			if got := out.String(); got != tt.out {
diff --git a/internal/testutil/testutil.go b/internal/testutil/testutil.go
new file mode 100644
index 0000000..9ac7711
--- /dev/null
+++ b/internal/testutil/testutil.go
@@ -0,0 +1,40 @@
+// Package testutil provides shared test helpers.
+package testutil
+
+import "testing"
+
+// EqErr checks whether err matches the expected message msg.
+// Returns true only when both are empty (no error expected, none received).
+func EqErr(t *testing.T, id string, err error, msg string) bool {
+	t.Helper()
+	if err == nil && msg == "" {
+		return true
+	}
+	if err == nil && msg != "" {
+		t.Errorf("case [%s]: expected error message %q; but got nothing", id, msg)
+		return false
+	}
+	if err != nil && msg != err.Error() {
+		t.Errorf("case [%s]: expected error message %q; but got %q", id, msg, err)
+	}
+	return false
+}
+
+// Ptr returns a pointer to the given string.
+func Ptr(s string) *string { return &s }
+
+// Str returns the string value of a *string, or "<nil>" if nil.
+func Str(s *string) string {
+	if s == nil {
+		return "<nil>"
+	}
+	return *s
+}
+
+// EqPtr returns whether two *string values are equal.
+func EqPtr(a, b *string) bool {
+	if a == nil || b == nil {
+		return a == b
+	}
+	return *a == *b
+}
diff --git a/main.go b/main.go
index c25e5cc..bb26330 100644
--- a/main.go
+++ b/main.go
@@ -24,9 +24,12 @@
 //
 // embedmd supports two flags:
 // -d: will print the difference of the input file with what the output
-//     would have been if executed.
+//
+//	would have been if executed.
+//
 // -w: rewrites the given files rather than writing the output to the standard
-//     output.
+//
+//	output.
 //
 // For more information on the format of the commands, read the documentation
 // of the github.com/campoy/embedmd/embedmd package.
diff --git a/main_test.go b/main_test.go
index 62d1b73..e073179 100644
--- a/main_test.go
+++ b/main_test.go
@@ -19,6 +19,8 @@ import (
 	"os"
 	"strings"
 	"testing"
+
+	"github.com/campoy/embedmd/internal/testutil"
 )
 
 func TestEmbedStreams(t *testing.T) {
@@ -65,7 +67,7 @@ func TestEmbedStreams(t *testing.T) {
 		buf := &bytes.Buffer{}
 		stdout = buf
 		foundDiff, err := embed(nil, tt.w, tt.d)
-		if !eqErr(t, tt.name, err, tt.err) {
+		if !testutil.EqErr(t, tt.name, err, tt.err) {
 			continue
 		}
 		if got := buf.String(); tt.out != got {
@@ -112,7 +114,7 @@ func TestEmbedFiles(t *testing.T) {
 		}
 
 		_, err := embed([]string{"docs.md"}, tt.w, tt.d)
-		if !eqErr(t, tt.name, err, tt.err) {
+		if !testutil.EqErr(t, tt.name, err, tt.err) {
 			continue
 		}
 		if got := f.buf.String(); tt.out != got {
@@ -122,20 +124,6 @@ func TestEmbedFiles(t *testing.T) {
 	}
 }
 
-func eqErr(t *testing.T, id string, err error, msg string) bool {
-	if err == nil && msg == "" {
-		return true
-	}
-	if err == nil && msg != "" {
-		t.Errorf("case [%s]: expected error message %q; but got nothing", id, msg)
-		return false
-	}
-	if err != nil && msg != err.Error() {
-		t.Errorf("case [%s]: expected error message %q; but got %q", id, msg, err)
-	}
-	return false
-}
-
 type fakeFile struct {
 	io.ReadCloser
 	buf bytes.Buffer