Validate config dir is used in tests

Author: devm33

dotnet/test/SessionTests.cs

@@ -331,6 +331,12 @@ public async Task Should_Create_Session_With_Custom_Config_Dir()
 
         Assert.Matches(@"^[a-f0-9-]+$", session.SessionId);
 
+        // Verify config.json was written to the custom config dir
+        var configPath = Path.Combine(customConfigDir, "github-copilot", "config.json");
+        Assert.True(File.Exists(configPath), $"Expected config.json at {configPath}");
+        var configContent = System.Text.Json.JsonDocument.Parse(await File.ReadAllTextAsync(configPath));
+        Assert.Equal(session.SessionId, configContent.RootElement.GetProperty("sessionId").GetString());
+
         // Session should work normally with custom config dir
         await session.SendAsync(new MessageOptions { Prompt = "What is 1+1?" });
         var assistantMessage = await TestHelper.GetFinalAssistantMessageAsync(session);

go/e2e/session_test.go

@@ -1,6 +1,8 @@
 package e2e
 
 import (
+	"encoding/json"
+	"os"
 	"regexp"
 	"strings"
 	"testing"
@@ -704,6 +706,20 @@ func TestSession(t *testing.T) {
 			t.Errorf("Expected session ID to match UUID pattern, got %q", session.SessionID)
 		}
 
+		// Verify config.json was written to the custom config dir
+		configPath := customConfigDir + "/github-copilot/config.json"
+		configData, err := os.ReadFile(configPath)
+		if err != nil {
+			t.Fatalf("Failed to read config.json at %s: %v", configPath, err)
+		}
+		var configContent map[string]interface{}
+		if err := json.Unmarshal(configData, &configContent); err != nil {
+			t.Fatalf("Failed to parse config.json: %v", err)
+		}
+		if configContent["sessionId"] != session.SessionID {
+			t.Errorf("Expected config.json sessionId to be %q, got %v", session.SessionID, configContent["sessionId"])
+		}
+
 		// Session should work normally with custom config dir
 		_, err = session.Send(copilot.MessageOptions{Prompt: "What is 1+1?"})
 		if err != nil {

nodejs/test/e2e/session.test.ts

@@ -1,3 +1,4 @@
+import * as fs from "node:fs";
 import { describe, expect, it, onTestFinished } from "vitest";
 import { ParsedHttpExchange } from "../../../test/harness/replayingCapiProxy.js";
 import { CopilotClient } from "../../src/index.js";
@@ -343,6 +344,12 @@ describe("Sessions", async () => {
 
         expect(session.sessionId).toMatch(/^[a-f0-9-]+$/);
 
+        // Verify config.json was written to the custom config dir
+        const configPath = `${customConfigDir}/github-copilot/config.json`;
+        expect(fs.existsSync(configPath)).toBe(true);
+        const configContent = JSON.parse(fs.readFileSync(configPath, "utf-8"));
+        expect(configContent).toHaveProperty("sessionId", session.sessionId);
+
         // Session should work normally with custom config dir
         await session.send({ prompt: "What is 1+1?" });
         const assistantMessage = await getFinalAssistantMessage(session);

python/e2e/test_session.py

@@ -361,13 +361,21 @@ def on_event(event):
         assert "300" in assistant_message.data.content
 
     async def test_should_create_session_with_custom_config_dir(self, ctx: E2ETestContext):
+        import json
         import os
 
         custom_config_dir = os.path.join(ctx.home_dir, "custom-config")
         session = await ctx.client.create_session({"config_dir": custom_config_dir})
 
         assert session.session_id
 
+        # Verify config.json was written to the custom config dir
+        config_path = os.path.join(custom_config_dir, "github-copilot", "config.json")
+        assert os.path.exists(config_path), f"Expected config.json at {config_path}"
+        with open(config_path) as f:
+            config_content = json.load(f)
+        assert config_content.get("sessionId") == session.session_id
+
         # Session should work normally with custom config dir
         await session.send({"prompt": "What is 1+1?"})
         assistant_message = await get_final_assistant_message(session)