Mock MCP client for testing

Author: MegaGrindStone

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Add refresh title feature to refresh chat title from LLM
 - Implement MCP Prompts functionality
+- Add `MCPClient` interface for testing purposes
 
 ### Fixed
 

cmd/server/main.go

@@ -57,6 +57,7 @@ func main() {
 	}
 
 	mcpClients, stdIOCmds := populateMCPClients(cfg, mcpClientInfo, logger)
+	mcpClis := make([]handlers.MCPClient, len(mcpClients))
 
 	for i, cli := range mcpClients {
 		logger.Info("Connecting to MCP server", slog.Int("index", i))
@@ -70,12 +71,12 @@ func main() {
 		}
 		connectCancel()
 
-		mcpClients[i] = cli
+		mcpClis[i] = cli
 
 		logger.Info("Connected to MCP server", slog.String("name", mcpClients[i].ServerInfo().Name))
 	}
 
-	m, err := handlers.NewMain(llm, titleGen, boltDB, mcpClients, logger)
+	m, err := handlers.NewMain(llm, titleGen, boltDB, mcpClis, logger)
 	if err != nil {
 		panic(err)
 	}

internal/handlers/main.go

@@ -38,6 +38,20 @@ type Store interface {
 	UpdateMessage(ctx context.Context, chatID string, message models.Message) error
 }
 
+// MCPClient defines the interface for interacting with an MCP server.
+// This allows for mocking in tests.
+type MCPClient interface {
+	ServerInfo() mcp.Info
+	ToolServerSupported() bool
+	ResourceServerSupported() bool
+	PromptServerSupported() bool
+	ListTools(ctx context.Context, params mcp.ListToolsParams) (mcp.ListToolsResult, error)
+	ListResources(ctx context.Context, params mcp.ListResourcesParams) (mcp.ListResourcesResult, error)
+	ListPrompts(ctx context.Context, params mcp.ListPromptsParams) (mcp.ListPromptResult, error)
+	GetPrompt(ctx context.Context, params mcp.GetPromptParams) (mcp.GetPromptResult, error)
+	CallTool(ctx context.Context, params mcp.CallToolParams) (mcp.CallToolResult, error)
+}
+
 // Main handles the core functionality of the chat application, managing server-sent events,
 // HTML templates, and interactions between the LLM and Store components.
 type Main struct {
@@ -48,7 +62,7 @@ type Main struct {
 	titleGenerator TitleGenerator
 	store          Store
 
-	mcpClients []*mcp.Client
+	mcpClients []MCPClient
 
 	servers   []mcp.Info
 	tools     []mcp.Tool
@@ -73,7 +87,7 @@ func NewMain(
 	llm LLM,
 	titleGen TitleGenerator,
 	store Store,
-	mcpClients []*mcp.Client,
+	mcpClients []MCPClient,
 	logger *slog.Logger,
 ) (Main, error) {
 	// We parse templates from three distinct directories to separate layout, pages, and partial views