package renderers
import (
"testing"
"github.com/google/go-cmp/cmp"
"github.com/ollama/ollama/api"
)
func TestLFM2Renderer(t *testing.T) {
tests := []struct {
name string
messages []api.Message
tools []api.Tool
thinkValue *api.ThinkValue
expected string
}{
{
name: "basic user message",
messages: []api.Message{
{Role: "user", Content: "Hello!"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nHello!<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "basic with system message",
messages: []api.Message{
{Role: "system", Content: "You are a helpful assistant."},
{Role: "user", Content: "Hello!"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>system\nYou are a helpful assistant.<|im_end|>\n<|im_start|>user\nHello!<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "multiple system messages rendered separately",
messages: []api.Message{
{Role: "system", Content: "First instruction."},
{Role: "system", Content: "Second instruction."},
{Role: "user", Content: "Hello!"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>system\nFirst instruction.<|im_end|>\n<|im_start|>system\nSecond instruction.<|im_end|>\n<|im_start|>user\nHello!<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "multi-turn conversation",
messages: []api.Message{
{Role: "user", Content: "What is 2+2?"},
{Role: "assistant", Content: "The answer is 4."},
{Role: "user", Content: "Thanks!"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nWhat is 2+2?<|im_end|>\n<|im_start|>assistant\nThe answer is 4.<|im_end|>\n<|im_start|>user\nThanks!<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "only system message",
messages: []api.Message{
{Role: "system", Content: "You are helpful."},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>system\nYou are helpful.<|im_end|>\n<|im_start|>assistant\n",
},
{
// When assistant is the LAST assistant, thinking is preserved (even with keep_past_thinking=false)
name: "user-assistant-user: last assistant preserves thinking",
messages: []api.Message{
{Role: "user", Content: "Q1"},
{Role: "assistant", Content: "reasoningA1"},
{Role: "user", Content: "Q2"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nQ1<|im_end|>\n<|im_start|>assistant\nreasoningA1<|im_end|>\n<|im_start|>user\nQ2<|im_end|>\n<|im_start|>assistant\n",
},
{
// With two assistants, first is stripped (not last), second preserved (is last)
name: "multi-turn thinking: first stripped, second preserved",
messages: []api.Message{
{Role: "user", Content: "Q1"},
{Role: "assistant", Content: "reason1A1"},
{Role: "user", Content: "Q2"},
{Role: "assistant", Content: "reason2A2"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nQ1<|im_end|>\n<|im_start|>assistant\nA1<|im_end|>\n<|im_start|>user\nQ2<|im_end|>\n<|im_start|>assistant\nreason2A2<|im_end|>\n<|im_start|>assistant\n",
},
{
// With thinking enabled (keep_past_thinking=true), both preserved
name: "multi-turn thinking: both preserved when thinking enabled",
messages: []api.Message{
{Role: "user", Content: "Q1"},
{Role: "assistant", Content: "reason1A1"},
{Role: "user", Content: "Q2"},
{Role: "assistant", Content: "reason2A2"},
},
thinkValue: &api.ThinkValue{Value: true},
expected: "<|im_start|>user\nQ1<|im_end|>\n<|im_start|>assistant\nreason1A1<|im_end|>\n<|im_start|>user\nQ2<|im_end|>\n<|im_start|>assistant\nreason2A2<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "assistant with tool calls",
messages: []api.Message{
{Role: "user", Content: "What's the weather?"},
{
Role: "assistant",
ToolCalls: []api.ToolCall{
{
Function: api.ToolCallFunction{
Name: "get_weather",
Arguments: testArgs(map[string]any{
"location": "Paris",
}),
},
},
},
},
},
thinkValue: &api.ThinkValue{Value: false},
expected: `<|im_start|>user` + "\n" + `What's the weather?<|im_end|>` + "\n" + `<|im_start|>assistant` + "\n" + `<|tool_call_start|>{"arguments":{"location":"Paris"},"name":"get_weather"}<|tool_call_end|><|im_end|>` + "\n" + `<|im_start|>assistant` + "\n",
},
{
name: "assistant with content and tool calls",
messages: []api.Message{
{Role: "user", Content: "What's the weather in Paris?"},
{
Role: "assistant",
Content: "Let me check.",
ToolCalls: []api.ToolCall{
{
Function: api.ToolCallFunction{
Name: "get_weather",
Arguments: testArgs(map[string]any{
"location": "Paris",
}),
},
},
},
},
},
thinkValue: &api.ThinkValue{Value: false},
expected: `<|im_start|>user` + "\n" + `What's the weather in Paris?<|im_end|>` + "\n" + `<|im_start|>assistant` + "\n" + `Let me check.<|tool_call_start|>{"arguments":{"location":"Paris"},"name":"get_weather"}<|tool_call_end|><|im_end|>` + "\n" + `<|im_start|>assistant` + "\n",
},
{
name: "tool response",
messages: []api.Message{
{Role: "user", Content: "What's the weather?"},
{Role: "assistant", Content: "Let me check."},
{Role: "tool", Content: "22C, Sunny"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nWhat's the weather?<|im_end|>\n<|im_start|>assistant\nLet me check.<|im_end|>\n<|im_start|>tool\n22C, Sunny<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "multiple tool calls",
messages: []api.Message{
{Role: "user", Content: "Get weather for Paris and London"},
{
Role: "assistant",
ToolCalls: []api.ToolCall{
{
Function: api.ToolCallFunction{
Name: "get_weather",
Arguments: testArgs(map[string]any{
"location": "Paris",
}),
},
},
{
Function: api.ToolCallFunction{
Name: "get_weather",
Arguments: testArgs(map[string]any{
"location": "London",
}),
},
},
},
},
},
thinkValue: &api.ThinkValue{Value: false},
expected: `<|im_start|>user` + "\n" + `Get weather for Paris and London<|im_end|>` + "\n" + `<|im_start|>assistant` + "\n" + `<|tool_call_start|>{"arguments":{"location":"Paris"},"name":"get_weather"}<|tool_call_end|><|tool_call_start|>{"arguments":{"location":"London"},"name":"get_weather"}<|tool_call_end|><|im_end|>` + "\n" + `<|im_start|>assistant` + "\n",
},
{
name: "tools definitions with system message",
messages: []api.Message{
{Role: "system", Content: "You are helpful."},
{Role: "user", Content: "What's the weather?"},
},
tools: []api.Tool{
{
Type: "function",
Function: api.ToolFunction{
Name: "get_weather",
Description: "Get current weather",
Parameters: api.ToolFunctionParameters{
Type: "object",
Properties: testPropsMap(map[string]api.ToolProperty{
"location": {
Type: api.PropertyType{"string"},
Description: "City name",
},
}),
Required: []string{"location"},
},
},
},
},
thinkValue: &api.ThinkValue{Value: false},
expected: `<|im_start|>system` + "\n" + `You are helpful.` + "\n" + `List of tools: [{"type":"function","function":{"name":"get_weather","description":"Get current weather","parameters":{"type":"object","required":["location"],"properties":{"location":{"type":"string","description":"City name"}}}}}]<|im_end|>` + "\n" + `<|im_start|>user` + "\n" + `What's the weather?<|im_end|>` + "\n" + `<|im_start|>assistant` + "\n",
},
{
name: "tools definitions without system message",
messages: []api.Message{
{Role: "user", Content: "What's the weather?"},
},
tools: []api.Tool{
{
Type: "function",
Function: api.ToolFunction{
Name: "get_weather",
Description: "Get current weather",
Parameters: api.ToolFunctionParameters{
Type: "object",
Properties: testPropsMap(map[string]api.ToolProperty{
"location": {
Type: api.PropertyType{"string"},
Description: "City name",
},
}),
Required: []string{"location"},
},
},
},
},
thinkValue: &api.ThinkValue{Value: false},
expected: `<|im_start|>system` + "\n" + `List of tools: [{"type":"function","function":{"name":"get_weather","description":"Get current weather","parameters":{"type":"object","required":["location"],"properties":{"location":{"type":"string","description":"City name"}}}}}]<|im_end|>` + "\n" + `<|im_start|>user` + "\n" + `What's the weather?<|im_end|>` + "\n" + `<|im_start|>assistant` + "\n",
},
{
name: "multiple tools without system message",
messages: []api.Message{
{Role: "user", Content: "Hello"},
},
tools: []api.Tool{
{
Type: "function",
Function: api.ToolFunction{
Name: "get_weather",
Description: "Get weather",
},
},
{
Type: "function",
Function: api.ToolFunction{
Name: "get_time",
Description: "Get time",
},
},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>system\nList of tools: [{\"type\":\"function\",\"function\":{\"name\":\"get_weather\",\"description\":\"Get weather\",\"parameters\":{\"type\":\"\",\"properties\":null}}}, {\"type\":\"function\",\"function\":{\"name\":\"get_time\",\"description\":\"Get time\",\"parameters\":{\"type\":\"\",\"properties\":null}}}]<|im_end|>\n<|im_start|>user\nHello<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "user-tool sequence",
messages: []api.Message{
{Role: "user", Content: "Check weather"},
{Role: "tool", Content: "22C"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nCheck weather<|im_end|>\n<|im_start|>tool\n22C<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "full tool call cycle",
messages: []api.Message{
{Role: "user", Content: "Check weather"},
{Role: "assistant", Content: "Let me check"},
{Role: "tool", Content: "22C"},
{Role: "assistant", Content: "It's 22C"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nCheck weather<|im_end|>\n<|im_start|>assistant\nLet me check<|im_end|>\n<|im_start|>tool\n22C<|im_end|>\n<|im_start|>assistant\nIt's 22C<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "unicode content",
messages: []api.Message{
{Role: "user", Content: "你好世界! مرحبا 🌍"},
{Role: "assistant", Content: "Hello! 👋"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\n你好世界! مرحبا 🌍<|im_end|>\n<|im_start|>assistant\nHello! 👋<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "newlines in content",
messages: []api.Message{
{Role: "user", Content: "Line 1\nLine 2\n\nLine 4"},
{Role: "assistant", Content: "Response with\nmultiple\nlines"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nLine 1\nLine 2\n\nLine 4<|im_end|>\n<|im_start|>assistant\nResponse with\nmultiple\nlines<|im_end|>\n<|im_start|>assistant\n",
},
{
name: "empty assistant content",
messages: []api.Message{
{Role: "user", Content: "Hello"},
{Role: "assistant", Content: ""},
{Role: "user", Content: "OK"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nHello<|im_end|>\n<|im_start|>assistant\n<|im_end|>\n<|im_start|>user\nOK<|im_end|>\n<|im_start|>assistant\n",
},
{
// Generation prompt does NOT include - model outputs it
name: "generation prompt has no think tag",
messages: []api.Message{
{Role: "user", Content: "Think hard"},
},
thinkValue: &api.ThinkValue{Value: true},
expected: "<|im_start|>user\nThink hard<|im_end|>\n<|im_start|>assistant\n",
},
{
// Interleaved: thinking before tool call - last assistant preserves thinking
name: "thinking before tool call (last assistant)",
messages: []api.Message{
{Role: "user", Content: "What's the weather?"},
{
Role: "assistant",
Content: "I need to check the weather",
ToolCalls: []api.ToolCall{
{
Function: api.ToolCallFunction{
Name: "get_weather",
Arguments: testArgs(map[string]any{
"location": "Paris",
}),
},
},
},
},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nWhat's the weather?<|im_end|>\n<|im_start|>assistant\nI need to check the weather<|tool_call_start|>{\"arguments\":{\"location\":\"Paris\"},\"name\":\"get_weather\"}<|tool_call_end|><|im_end|>\n<|im_start|>assistant\n",
},
{
// Two assistants with tool calls - first has thinking stripped
name: "two assistants with tools: first thinking stripped",
messages: []api.Message{
{Role: "user", Content: "What's the weather?"},
{
Role: "assistant",
Content: "checking",
ToolCalls: []api.ToolCall{
{
Function: api.ToolCallFunction{
Name: "get_weather",
Arguments: testArgs(map[string]any{
"location": "Paris",
}),
},
},
},
},
{Role: "tool", Content: "22C"},
{Role: "assistant", Content: "got resultIt's 22C!"},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nWhat's the weather?<|im_end|>\n<|im_start|>assistant\n<|tool_call_start|>{\"arguments\":{\"location\":\"Paris\"},\"name\":\"get_weather\"}<|tool_call_end|><|im_end|>\n<|im_start|>tool\n22C<|im_end|>\n<|im_start|>assistant\ngot resultIt's 22C!<|im_end|>\n<|im_start|>assistant\n",
},
{
// Two assistants with tools - both preserved when thinking enabled
name: "two assistants with tools: both preserved when thinking enabled",
messages: []api.Message{
{Role: "user", Content: "What's the weather?"},
{
Role: "assistant",
Content: "checking",
ToolCalls: []api.ToolCall{
{
Function: api.ToolCallFunction{
Name: "get_weather",
Arguments: testArgs(map[string]any{
"location": "Paris",
}),
},
},
},
},
{Role: "tool", Content: "22C"},
{Role: "assistant", Content: "got resultIt's 22C!"},
},
thinkValue: &api.ThinkValue{Value: true},
expected: "<|im_start|>user\nWhat's the weather?<|im_end|>\n<|im_start|>assistant\nchecking<|tool_call_start|>{\"arguments\":{\"location\":\"Paris\"},\"name\":\"get_weather\"}<|tool_call_end|><|im_end|>\n<|im_start|>tool\n22C<|im_end|>\n<|im_start|>assistant\ngot resultIt's 22C!<|im_end|>\n<|im_start|>assistant\n",
},
{
// Content before thinking before tool call
name: "content then thinking then tool call",
messages: []api.Message{
{Role: "user", Content: "What's the weather?"},
{
Role: "assistant",
Content: "Let me check.Using weather API",
ToolCalls: []api.ToolCall{
{
Function: api.ToolCallFunction{
Name: "get_weather",
Arguments: testArgs(map[string]any{
"location": "Paris",
}),
},
},
},
},
},
thinkValue: &api.ThinkValue{Value: false},
expected: "<|im_start|>user\nWhat's the weather?<|im_end|>\n<|im_start|>assistant\nLet me check.Using weather API<|tool_call_start|>{\"arguments\":{\"location\":\"Paris\"},\"name\":\"get_weather\"}<|tool_call_end|><|im_end|>\n<|im_start|>assistant\n",
},
}
renderer := &LFM2Renderer{IsThinking: true}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
rendered, err := renderer.Render(tt.messages, tt.tools, tt.thinkValue)
if err != nil {
t.Fatalf("Render() error = %v", err)
}
if diff := cmp.Diff(tt.expected, rendered); diff != "" {
t.Errorf("Render() mismatch (-want +got):\n%s", diff)
}
})
}
}