test(config): add migration tests for litellm provider

* Implement tests for migrating configuration from v1 to v2 for the litellm provider.
* Validate the structure and values of the migrated configuration.
* Ensure migration rejects newer versions of the configuration.
fix(validate): enhance AI provider validation logic
* Consolidate provider validation into a dedicated method.
* Ensure at least one provider is specified and validate its type.
* Check for required fields based on provider type.
fix(mcpserver): update tool set to use new enrichment tool
* Replace RetryMetadataTool with RetryEnrichmentTool in the ToolSet.
fix(tools): refactor tools to use embedding and metadata runners
* Update tools to utilize EmbeddingRunner and MetadataRunner instead of Provider.
* Adjust method calls to align with the new runner interfaces.

internal/config/validate_test.go

@@ -7,28 +7,23 @@ import (
 
 func validConfig() Config {
 	return Config{
-		Server: ServerConfig{Port: 8080},
-		MCP:    MCPConfig{Path: "/mcp", SessionTimeout: 10 * time.Minute},
+		Version: CurrentConfigVersion,
+		Server:  ServerConfig{Port: 8080},
+		MCP:     MCPConfig{Path: "/mcp", SessionTimeout: 10 * time.Minute},
 		Auth: AuthConfig{
 			Keys: []APIKey{{ID: "test", Value: "secret"}},
 		},
 		Database: DatabaseConfig{URL: "postgres://example"},
 		AI: AIConfig{
-			Provider: "litellm",
-			Embeddings: AIEmbeddingConfig{
+			Providers: map[string]ProviderConfig{
+				"default": {Type: "litellm", BaseURL: "http://localhost:4000/v1", APIKey: "key"},
+			},
+			Embeddings: EmbeddingsRoleConfig{
 				Dimensions: 1536,
+				Primary:    RoleTarget{Provider: "default", Model: "text-embed"},
 			},
-			LiteLLM: LiteLLMConfig{
-				BaseURL: "http://localhost:4000/v1",
-				APIKey:  "key",
-			},
-			Ollama: OllamaConfig{
-				BaseURL: "http://localhost:11434/v1",
-				APIKey:  "ollama",
-			},
-			OpenRouter: OpenRouterAIConfig{
-				BaseURL: "https://openrouter.ai/api/v1",
-				APIKey:  "key",
+			Metadata: MetadataRoleConfig{
+				Primary: RoleTarget{Provider: "default", Model: "gpt-4"},
 			},
 		},
 		Search:  SearchConfig{DefaultLimit: 10, MaxLimit: 50},
@@ -36,29 +31,44 @@ func validConfig() Config {
 	}
 }
 
-func TestValidateAcceptsSupportedProviders(t *testing.T) {
-	cfg := validConfig()
-	if err := cfg.Validate(); err != nil {
-		t.Fatalf("Validate litellm error = %v", err)
-	}
-
-	cfg.AI.Provider = "ollama"
-	if err := cfg.Validate(); err != nil {
-		t.Fatalf("Validate ollama error = %v", err)
-	}
-
-	cfg.AI.Provider = "openrouter"
-	if err := cfg.Validate(); err != nil {
-		t.Fatalf("Validate openrouter error = %v", err)
+func TestValidateAcceptsSupportedProviderTypes(t *testing.T) {
+	for _, providerType := range []string{"litellm", "ollama", "openrouter"} {
+		cfg := validConfig()
+		p := cfg.AI.Providers["default"]
+		p.Type = providerType
+		cfg.AI.Providers["default"] = p
+		if err := cfg.Validate(); err != nil {
+			t.Fatalf("Validate %s error = %v", providerType, err)
+		}
 	}
 }
 
-func TestValidateRejectsInvalidProvider(t *testing.T) {
+func TestValidateRejectsInvalidProviderType(t *testing.T) {
 	cfg := validConfig()
-	cfg.AI.Provider = "unknown"
+	p := cfg.AI.Providers["default"]
+	p.Type = "unknown"
+	cfg.AI.Providers["default"] = p
 
 	if err := cfg.Validate(); err == nil {
-		t.Fatal("Validate() error = nil, want error for unsupported provider")
+		t.Fatal("Validate() error = nil, want error for unsupported provider type")
+	}
+}
+
+func TestValidateRejectsChainWithUnknownProvider(t *testing.T) {
+	cfg := validConfig()
+	cfg.AI.Metadata.Primary = RoleTarget{Provider: "does-not-exist", Model: "x"}
+
+	if err := cfg.Validate(); err == nil {
+		t.Fatal("Validate() error = nil, want error for chain referencing unknown provider")
+	}
+}
+
+func TestValidateRejectsEmptyProviders(t *testing.T) {
+	cfg := validConfig()
+	cfg.AI.Providers = map[string]ProviderConfig{}
+
+	if err := cfg.Validate(); err == nil {
+		t.Fatal("Validate() error = nil, want error for empty providers")
 	}
 }