Add comprehensive test suite for v2 module with mock provider

Cover all core library logic (Client, Model, Chat, middleware, streaming,
message conversion, request building) using a configurable mock provider
that avoids real API calls. ~50 tests across 7 files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

v2/request_test.go

@@ -0,0 +1,137 @@
+package llm
+
+import (
+	"context"
+	"testing"
+)
+
+func TestWithTemperature(t *testing.T) {
+	cfg := &requestConfig{}
+	WithTemperature(0.7)(cfg)
+	if cfg.temperature == nil || *cfg.temperature != 0.7 {
+		t.Errorf("expected temperature 0.7, got %v", cfg.temperature)
+	}
+}
+
+func TestWithMaxTokens(t *testing.T) {
+	cfg := &requestConfig{}
+	WithMaxTokens(256)(cfg)
+	if cfg.maxTokens == nil || *cfg.maxTokens != 256 {
+		t.Errorf("expected maxTokens 256, got %v", cfg.maxTokens)
+	}
+}
+
+func TestWithTopP(t *testing.T) {
+	cfg := &requestConfig{}
+	WithTopP(0.95)(cfg)
+	if cfg.topP == nil || *cfg.topP != 0.95 {
+		t.Errorf("expected topP 0.95, got %v", cfg.topP)
+	}
+}
+
+func TestWithStop(t *testing.T) {
+	cfg := &requestConfig{}
+	WithStop("END", "STOP", "###")(cfg)
+	if len(cfg.stop) != 3 {
+		t.Fatalf("expected 3 stop sequences, got %d", len(cfg.stop))
+	}
+	if cfg.stop[0] != "END" || cfg.stop[1] != "STOP" || cfg.stop[2] != "###" {
+		t.Errorf("unexpected stop sequences: %v", cfg.stop)
+	}
+}
+
+func TestWithTools(t *testing.T) {
+	tool := DefineSimple("test", "A test tool", func(ctx context.Context) (string, error) {
+		return "ok", nil
+	})
+	tb := NewToolBox(tool)
+
+	cfg := &requestConfig{}
+	WithTools(tb)(cfg)
+	if cfg.tools == nil {
+		t.Fatal("expected tools to be set")
+	}
+	if len(cfg.tools.AllTools()) != 1 {
+		t.Errorf("expected 1 tool, got %d", len(cfg.tools.AllTools()))
+	}
+}
+
+func TestBuildProviderRequest(t *testing.T) {
+	tool := DefineSimple("greet", "Greets", func(ctx context.Context) (string, error) {
+		return "hi", nil
+	})
+	tb := NewToolBox(tool)
+
+	temp := 0.8
+	maxTok := 512
+	topP := 0.9
+
+	cfg := &requestConfig{
+		tools:       tb,
+		temperature: &temp,
+		maxTokens:   &maxTok,
+		topP:        &topP,
+		stop:        []string{"END"},
+	}
+
+	msgs := []Message{
+		SystemMessage("be nice"),
+		UserMessage("hello"),
+	}
+
+	req := buildProviderRequest("test-model", msgs, cfg)
+
+	if req.Model != "test-model" {
+		t.Errorf("expected model 'test-model', got %q", req.Model)
+	}
+	if len(req.Messages) != 2 {
+		t.Fatalf("expected 2 messages, got %d", len(req.Messages))
+	}
+	if req.Messages[0].Role != "system" {
+		t.Errorf("expected first message role='system', got %q", req.Messages[0].Role)
+	}
+	if req.Messages[1].Role != "user" {
+		t.Errorf("expected second message role='user', got %q", req.Messages[1].Role)
+	}
+	if req.Temperature == nil || *req.Temperature != 0.8 {
+		t.Errorf("expected temperature 0.8, got %v", req.Temperature)
+	}
+	if req.MaxTokens == nil || *req.MaxTokens != 512 {
+		t.Errorf("expected maxTokens 512, got %v", req.MaxTokens)
+	}
+	if req.TopP == nil || *req.TopP != 0.9 {
+		t.Errorf("expected topP 0.9, got %v", req.TopP)
+	}
+	if len(req.Stop) != 1 || req.Stop[0] != "END" {
+		t.Errorf("expected stop=[END], got %v", req.Stop)
+	}
+	if len(req.Tools) != 1 {
+		t.Fatalf("expected 1 tool, got %d", len(req.Tools))
+	}
+	if req.Tools[0].Name != "greet" {
+		t.Errorf("expected tool name 'greet', got %q", req.Tools[0].Name)
+	}
+}
+
+func TestBuildProviderRequest_EmptyConfig(t *testing.T) {
+	cfg := &requestConfig{}
+	msgs := []Message{UserMessage("hi")}
+
+	req := buildProviderRequest("model", msgs, cfg)
+
+	if req.Temperature != nil {
+		t.Errorf("expected nil temperature, got %v", req.Temperature)
+	}
+	if req.MaxTokens != nil {
+		t.Errorf("expected nil maxTokens, got %v", req.MaxTokens)
+	}
+	if req.TopP != nil {
+		t.Errorf("expected nil topP, got %v", req.TopP)
+	}
+	if len(req.Stop) != 0 {
+		t.Errorf("expected no stop sequences, got %v", req.Stop)
+	}
+	if len(req.Tools) != 0 {
+		t.Errorf("expected no tools, got %d", len(req.Tools))
+	}
+}