更新

internal_test.go

@@ -0,0 +1,20 @@
+package mailx
+
+import "testing"
+
+func TestFileBaseName(t *testing.T) {
+	cases := []struct{ in, want string }{
+		{"dir/file.txt", "file.txt"},
+		{`dir\file.txt`, "file.txt"},
+		{"/a/b/c.txt", "c.txt"},
+		{"file.txt", "file.txt"},
+		{"", "attachment"},
+		{"/", "attachment"},
+		{".", "attachment"},
+	}
+	for _, c := range cases {
+		if got := fileBaseName(c.in); got != c.want {
+			t.Errorf("fileBaseName(%q) = %q, want %q", c.in, got, c.want)
+		}
+	}
+}