test(handler): add some test cases for the read_file tool

Author: jochil

filesystemserver/handler_test.go

@@ -0,0 +1,70 @@
+package filesystemserver
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/mark3labs/mcp-go/mcp"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestReadfile_Valid(t *testing.T) {
+	// prepare temp directory
+	dir := t.TempDir()
+	content := "test-content"
+	err := os.WriteFile(filepath.Join(dir, "test"), []byte(content), 0644)
+	require.NoError(t, err)
+
+	handler, err := NewFilesystemHandler([]string{dir})
+	require.NoError(t, err)
+	request := mcp.CallToolRequest{}
+	request.Params.Name = "read_file"
+	request.Params.Arguments = map[string]any{
+		"path": filepath.Join(dir, "test"),
+	}
+
+	result, err := handler.handleReadFile(context.Background(), request)
+	require.NoError(t, err)
+	assert.Len(t, result.Content, 1)
+	assert.Equal(t, content, result.Content[0].(mcp.TextContent).Text)
+}
+
+func TestReadfile_Invalid(t *testing.T) {
+	dir := t.TempDir()
+	handler, err := NewFilesystemHandler([]string{dir})
+	require.NoError(t, err)
+
+	request := mcp.CallToolRequest{}
+	request.Params.Name = "read_file"
+	request.Params.Arguments = map[string]any{
+		"path": filepath.Join(dir, "test"),
+	}
+
+	result, err := handler.handleReadFile(context.Background(), request)
+	require.NoError(t, err)
+	assert.True(t, result.IsError)
+	assert.Contains(t, fmt.Sprint(result.Content[0]), "no such file or directory")
+}
+
+func TestReadfile_NoAccess(t *testing.T) {
+	dir1 := t.TempDir()
+	dir2 := t.TempDir()
+
+	handler, err := NewFilesystemHandler([]string{dir1})
+	require.NoError(t, err)
+
+	request := mcp.CallToolRequest{}
+	request.Params.Name = "read_file"
+	request.Params.Arguments = map[string]any{
+		"path": filepath.Join(dir2, "test"),
+	}
+
+	result, err := handler.handleReadFile(context.Background(), request)
+	require.NoError(t, err)
+	assert.True(t, result.IsError)
+	assert.Contains(t, fmt.Sprint(result.Content[0]), "access denied - path outside allowed directories")
+}