fix(llm): strip inline <think> reasoning from Dahl/MiniMax streams; dedupe identical parallel tool calls; hermetic config tests

internal/llm/think_test.go

@@ -0,0 +1,75 @@
+package llm
+
+import (
+	"strings"
+	"testing"
+)
+
+func run(chunks ...string) (string, string) {
+	var f thinkFilter
+	var streamed strings.Builder
+	for _, c := range chunks {
+		streamed.WriteString(f.push(c))
+	}
+	streamed.WriteString(f.finish())
+	return streamed.String(), f.out.String()
+}
+
+func TestThinkFilter(t *testing.T) {
+	cases := []struct {
+		name   string
+		chunks []string
+		want   string
+	}{
+		{"plain", []string{"Hallo ", "Welt"}, "Hallo Welt"},
+		{"block", []string{"<think>reasoning\n</think>\n\nHallo!"}, "Hallo!"},
+		{"split tags", []string{"<th", "ink>abc</th", "ink>", "\n\nHal", "lo"}, "Hallo"},
+		{"char by char", strings.Split("<think>x</think>Ja", ""), "Ja"},
+		{"stray close", []string{"Hallo!</think>\n\nHallo!"}, "Hallo!\n\nHallo!"},
+		{"unclosed with gap (Dahl)", []string{"<think>The user asks.\n\n\nHallo! Wie geht's?"}, "Hallo! Wie geht's?"},
+		{"gap streams live", []string{"<think>a\n", "\n", "\nAntw", "ort"}, "Antwort"},
+		{"gap outside block kept", []string{"A\n\n\nB"}, "A\n\n\nB"},
+		{"unclosed no gap", []string{"<think>nur Gedanken"}, "nur Gedanken"},
+		{"lt not a tag", []string{"a <b> c <", "3"}, "a <b> c <3"},
+		{"trailing partial", []string{"x <thi"}, "x <thi"},
+	}
+	for _, c := range cases {
+		streamed, out := run(c.chunks...)
+		if streamed != c.want || out != c.want {
+			t.Errorf("%s: streamed=%q out=%q want %q", c.name, streamed, out, c.want)
+		}
+	}
+}
+
+func TestParseStreamStripsThink(t *testing.T) {
+	sse := `data: {"choices":[{"delta":{"content":"","role":"assistant"}}]}
+
+data: {"choices":[{"delta":{"reasoning":"hidden"}}]}
+
+data: {"choices":[{"delta":{"content":"<think>The user"}}]}
+
+data: {"choices":[{"delta":{"content":" greets.\n</thi"}}]}
+
+data: {"choices":[{"delta":{"content":"nk>\n\nHallo!"}}]}
+
+data: {"choices":[{"delta":{},"finish_reason":"stop"}]}
+
+data: [DONE]
+`
+	var deltas []string
+	resp, err := parseStream(strings.NewReader(sse), func(s string) { deltas = append(deltas, s) })
+	if err != nil || resp.Content != "Hallo!" || strings.Join(deltas, "") != "Hallo!" {
+		t.Fatalf("%q %v %v", resp.Content, deltas, err)
+	}
+}
+
+// The answer after a swallowed </think> must be streamed incrementally, not only at the end.
+func TestThinkGapStreamsIncrementally(t *testing.T) {
+	var f thinkFilter
+	if v := f.push("<think>Überlegung\n\n\nHal"); v != "Hal" {
+		t.Fatalf("got %q", v)
+	}
+	if v := f.push("lo"); v != "lo" {
+		t.Fatalf("got %q", v)
+	}
+}