package common
import "testing"
// TestStripThinkTrailingParityWithPython pins down the exact behaviour of
// StripThinkTrailing so it stays in sync with the Python original
//
// re.sub(r"^.*", "", ans, flags=re.DOTALL)
//
// The Python regex is greedy: with re.DOTALL the leading `.*` matches as much
// as possible, so for an input with more than one the substitution
// strips everything up to and including the LAST marker. A non-greedy `*?`
// would diverge here and leave the tail-visible-portion of the response behind.
func TestStripThinkTrailingParityWithPython(t *testing.T) {
tests := []struct {
name string
in string
want string
}{
{
name: "no_think_tag_unchanged",
in: "plain answer, no tags",
want: "plain answer, no tags",
},
{
name: "single_think_block_stripped",
in: "hidden reasoningvisible answer",
want: "visible answer",
},
{
name: "multiline_single_think_block",
in: "\nline 1\nline 2\n\nvisible",
want: "\nvisible",
},
{
name: "two_think_blocks_greedy_strips_to_last",
// Python: greedy `^.*` strips
// "Apart1B", leaving "part2".
// A non-greedy form would have left "part1Bpart2".
in: "Apart1Bpart2",
want: "part2",
},
{
name: "two_think_blocks_with_answer_greedy",
// Mirrors a real-world malformed stream where the model
// re-emits a stray after the answer.
in: "reasoningAnswernoisereal tail",
want: "real tail",
},
{
name: "unclosed_think_tag_does_not_match",
// No at all — the helper requires the closing tag,
// so nothing is stripped and the original passes through.
in: "no closing tag here",
want: "no closing tag here",
},
{
name: "lookalike_closing_tag_strips_everything",
// Quirky but intentional parity case: the helper only requires
// the substring to be present, regardless of whether
// an opening exists. The Python original has the same
// behaviour, so the port must match — this is a pre-existing
// limitation, not a new bug.
in: "use to mean end, not the same as ",
want: "",
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := StripThinkTrailing(tt.in); got != tt.want {
t.Errorf("input: %q\n got: %q\n want: %q", tt.in, got, tt.want)
}
})
}
}