backend: extract parseOllamaContextLength, 100% coverage

pkg/backend/ollama.go

@@ -84,18 +84,26 @@ func (b *OllamaBackend) ContextLength(ctx context.Context) int {
 		return 0
 	}
 	defer resp.Body.Close()
+	cl := parseOllamaContextLength(resp.Body)
+	if cl > 0 {
+		b.ctxLength = cl
+		b.ctxModel = b.model
+	}
+	return cl
+}
+
+// parseOllamaContextLength extracts the context_length from an /api/show response body.
+func parseOllamaContextLength(r io.Reader) int {
 	var result struct {
 		ModelInfo map[string]any `json:"model_info"`
 	}
-	if json.NewDecoder(resp.Body).Decode(&result) != nil {
+	if json.NewDecoder(r).Decode(&result) != nil {
 		return 0
 	}
 	for k, v := range result.ModelInfo {
 		if strings.HasSuffix(k, ".context_length") {
 			if f, ok := v.(float64); ok && f > 0 {
-				b.ctxLength = int(f)
-				b.ctxModel = b.model
-				return b.ctxLength
+				return int(f)
 			}
 		}
 	}

pkg/backend/ollama_stream_test.go

@@ -140,3 +140,53 @@ func TestOllamaNDJSON_ScannerError(t *testing.T) {
 		t.Errorf("final = %+v", fin)
 	}
 }
+
+// --- parseOllamaContextLength ---
+
+func TestParseOllamaContextLength_Found(t *testing.T) {
+	body := `{"model_info":{"general.context_length":8192}}`
+	if cl := parseOllamaContextLength(strings.NewReader(body)); cl != 8192 {
+		t.Errorf("cl = %d; want 8192", cl)
+	}
+}
+
+func TestParseOllamaContextLength_DifferentPrefix(t *testing.T) {
+	body := `{"model_info":{"llama.context_length":4096}}`
+	if cl := parseOllamaContextLength(strings.NewReader(body)); cl != 4096 {
+		t.Errorf("cl = %d; want 4096", cl)
+	}
+}
+
+func TestParseOllamaContextLength_NoKey(t *testing.T) {
+	body := `{"model_info":{"general.embedding_length":768}}`
+	if cl := parseOllamaContextLength(strings.NewReader(body)); cl != 0 {
+		t.Errorf("cl = %d; want 0", cl)
+	}
+}
+
+func TestParseOllamaContextLength_EmptyModelInfo(t *testing.T) {
+	body := `{"model_info":{}}`
+	if cl := parseOllamaContextLength(strings.NewReader(body)); cl != 0 {
+		t.Errorf("cl = %d; want 0", cl)
+	}
+}
+
+func TestParseOllamaContextLength_MalformedJSON(t *testing.T) {
+	if cl := parseOllamaContextLength(strings.NewReader("not json")); cl != 0 {
+		t.Errorf("cl = %d; want 0", cl)
+	}
+}
+
+func TestParseOllamaContextLength_ZeroValue(t *testing.T) {
+	body := `{"model_info":{"general.context_length":0}}`
+	if cl := parseOllamaContextLength(strings.NewReader(body)); cl != 0 {
+		t.Errorf("cl = %d; want 0", cl)
+	}
+}
+
+func TestParseOllamaContextLength_NonNumeric(t *testing.T) {
+	body := `{"model_info":{"general.context_length":"not a number"}}`
+	if cl := parseOllamaContextLength(strings.NewReader(body)); cl != 0 {
+		t.Errorf("cl = %d; want 0", cl)
+	}
+}