diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 149d5c9..6cd7484 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go: ['1.16']
+        go: ['1.15', '1.16']
     steps:
     - name: Setup
       uses: actions/setup-go@v3
diff --git a/finder.go b/finder.go
index 757d0e5..df09dd8 100644
--- a/finder.go
+++ b/finder.go
@@ -1,7 +1,6 @@
 package sysfont
 
 import (
-	"os"
 	"path/filepath"
 	"strings"
 
@@ -43,14 +42,7 @@ func NewFinder(opts *FinderOpts) *Finder {
 	}
 
 	var fonts []*Font
-	walker := func(filename string, info os.FileInfo, err error) error {
-		if err != nil {
-			return err
-		}
-		if info.IsDir() {
-			return nil
-		}
-
+	findFonts(opts, func(filename string) error {
 		// Check file extension.
 		if extensions := opts.Extensions; len(extensions) > 0 {
 			extension := filepath.Ext(strings.ToLower(filename))
@@ -67,14 +59,7 @@ func NewFinder(opts *FinderOpts) *Finder {
 
 		fonts = append(fonts, matches...)
 		return nil
-	}
-
-	// Traverse OS font directories.
-	for _, dir := range opts.SearchPaths {
-		if err := filepath.Walk(dir, walker); err != nil {
-			continue
-		}
-	}
+	})
 
 	return &Finder{
 		fonts: fonts,
diff --git a/finder_dirwalk.go b/finder_dirwalk.go
new file mode 100644
index 0000000..d812713
--- /dev/null
+++ b/finder_dirwalk.go
@@ -0,0 +1,29 @@
+//go:build go1.16
+// +build go1.16
+
+package sysfont
+
+import (
+	"io/fs"
+	"path/filepath"
+)
+
+func findFonts(opts *FinderOpts, fn func(filename string) error) {
+	walker := func(filename string, info fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+
+		return fn(filename)
+	}
+
+	// Traverse OS font directories.
+	for _, dir := range opts.SearchPaths {
+		if err := filepath.WalkDir(dir, walker); err != nil {
+			continue
+		}
+	}
+}
diff --git a/finder_test.go b/finder_test.go
new file mode 100644
index 0000000..64feafd
--- /dev/null
+++ b/finder_test.go
@@ -0,0 +1,32 @@
+package sysfont
+
+import "testing"
+
+func TestFinder(t *testing.T) {
+	f := NewFinder(&FinderOpts{SearchPaths: []string{"testdata/fonts"}})
+	fonts := f.List()
+
+	// We expect Arial twice as we get double matches due to the lowercase and capitalised versions.
+	exp := []*Font{
+		{Name: "Arial", Family: "Arial", Filename: "testdata/fonts/arial.ttf"},
+		{Name: "Arial", Family: "Arial", Filename: "testdata/fonts/arial.ttf"},
+		{Name: "Dingbats", Family: "Dingbats", Filename: "testdata/fonts/dingbats.ttc"},
+		{Name: "Helvetica", Family: "Helvetica", Filename: "testdata/fonts/helvetica.otf"},
+	}
+
+	if len(fonts) != len(exp) {
+		t.Errorf("Expected %d fonts, got %d", len(exp), len(fonts))
+	}
+
+	for i, font := range fonts {
+		if font.Name != exp[i].Name {
+			t.Errorf("Expected font name %s, got %s", exp[i].Name, font.Name)
+		}
+		if font.Family != exp[i].Family {
+			t.Errorf("Expected font family %s, got %s", exp[i].Family, font.Family)
+		}
+		if font.Filename != exp[i].Filename {
+			t.Errorf("Expected font filename %s, got %s", exp[i].Filename, font.Filename)
+		}
+	}
+}
diff --git a/finder_walk.go b/finder_walk.go
new file mode 100644
index 0000000..d7645c9
--- /dev/null
+++ b/finder_walk.go
@@ -0,0 +1,29 @@
+//go:build !go1.16
+// +build !go1.16
+
+package sysfont
+
+import (
+	"os"
+	"path/filepath"
+)
+
+func findFonts(opts *FinderOpts, fn func(filename string) error) {
+	walker := func(filename string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+
+		return fn(filename)
+	}
+
+	// Traverse OS font directories.
+	for _, dir := range opts.SearchPaths {
+		if err := filepath.Walk(dir, walker); err != nil {
+			continue
+		}
+	}
+}
diff --git a/testdata/fonts/arial.ttf b/testdata/fonts/arial.ttf
new file mode 100644
index 0000000..e69de29
diff --git a/testdata/fonts/dingbats.ttc b/testdata/fonts/dingbats.ttc
new file mode 100644
index 0000000..e69de29
diff --git a/testdata/fonts/helvetica.otf b/testdata/fonts/helvetica.otf
new file mode 100644
index 0000000..e69de29