diff --git a/pkg/file/file_test.go b/pkg/file/file_test.go
new file mode 100644
index 000000000..c4dd223d5
--- /dev/null
+++ b/pkg/file/file_test.go
@@ -0,0 +1,76 @@
+package file
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestIsLocalDirExistingDirectory(t *testing.T) {
+	dir := t.TempDir()
+	abs, err := filepath.Abs(dir)
+	if err != nil {
+		t.Fatalf("abs: %v", err)
+	}
+
+	isLocal, name := IsLocalDir(dir)
+	if !isLocal {
+		t.Fatalf("IsLocalDir(%q) = false, want true", dir)
+	}
+	if name != abs {
+		t.Fatalf("name = %q, want %q", name, abs)
+	}
+}
+
+func TestIsLocalDirExistingFile(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "file.txt")
+	if err := os.WriteFile(path, []byte("x"), 0o600); err != nil {
+		t.Fatalf("write: %v", err)
+	}
+	abs, err := filepath.Abs(path)
+	if err != nil {
+		t.Fatalf("abs: %v", err)
+	}
+
+	isLocal, name := IsLocalDir(path)
+	if !isLocal {
+		t.Fatalf("IsLocalDir(%q) = false, want true", path)
+	}
+	if name != abs {
+		t.Fatalf("name = %q, want %q", name, abs)
+	}
+}
+
+func TestIsLocalDirRelativePathResolvesToAbsolute(t *testing.T) {
+	root := t.TempDir()
+	t.Chdir(root)
+
+	//nolint:gosec
+	if err := os.Mkdir("relsub", 0o755); err != nil {
+		t.Fatalf("mkdir: %v", err)
+	}
+
+	isLocal, name := IsLocalDir("relsub")
+	if !isLocal {
+		t.Fatalf("IsLocalDir(%q) = false, want true", "relsub")
+	}
+	if !filepath.IsAbs(name) {
+		t.Fatalf("name = %q, want an absolute path", name)
+	}
+	if resolved, err := filepath.Abs("relsub"); err == nil && name != resolved {
+		t.Fatalf("name = %q, want %q", name, resolved)
+	}
+}
+
+func TestIsLocalDirNonExistentPathReturnsNameUnchanged(t *testing.T) {
+	missing := filepath.Join(t.TempDir(), "does-not-exist")
+
+	isLocal, name := IsLocalDir(missing)
+	if isLocal {
+		t.Fatalf("IsLocalDir(%q) = true, want false", missing)
+	}
+	if name != missing {
+		t.Fatalf("name = %q, want %q", name, missing)
+	}
+}