test: Fix multi-user tests

CLAUDE.md

@@ -123,7 +123,14 @@ OAuth integration tests support both **automated** (Playwright) and **interactiv
 **Automated Testing (Default - Recommended for CI/CD):**
 - **Default fixtures**: `nc_oauth_client`, `nc_mcp_oauth_client` now use Playwright automation by default
 - Uses Playwright headless browser automation to complete OAuth flow programmatically
+- **Shared OAuth Client**: All test users authenticate using a single OAuth client (matching MCP server behavior)
+  - Single `client_id`/`client_secret` pair is registered and reused for all test users
+  - Stored in `.nextcloud_oauth_shared_test_client.json` with `force_register=False` for reuse
+  - Reduces OAuth client registrations and matches production MCP server architecture
 - All Playwright fixtures: `playwright_oauth_token`, `nc_oauth_client`, `nc_mcp_oauth_client`, `nc_oauth_client_playwright`, `nc_mcp_oauth_client_playwright`
+- Multi-user fixtures: `alice_oauth_token`, `bob_oauth_token`, `charlie_oauth_token`, `diana_oauth_token`
+  - All use `shared_oauth_client_credentials` fixture for consistent client credentials
+  - Each user gets unique access tokens via same OAuth client (like multiple users using the MCP server)
 - Requires: `NEXTCLOUD_HOST`, `NEXTCLOUD_USERNAME`, `NEXTCLOUD_PASSWORD` environment variables
 - Uses `pytest-playwright-asyncio` for async Playwright fixtures
 - Playwright configuration: Use pytest CLI args like `--browser firefox --headed` to customize
@@ -131,13 +138,13 @@ OAuth integration tests support both **automated** (Playwright) and **interactiv
 - Example:
   ```bash
   # Run all OAuth tests with automated Playwright flow using Firefox
-  uv run pytest tests/integration/test_oauth*.py --browser firefox -v
+  uv run pytest tests/server/test_oauth*.py --browser firefox -v
 
   # Run specific Playwright tests with visible browser for debugging
-  uv run pytest tests/integration/test_oauth_playwright.py --browser firefox --headed -v
+  uv run pytest tests/server/test_mcp_oauth.py --browser firefox --headed -v
 
   # Run with Chromium (default)
-  uv run pytest tests/integration/test_oauth.py -v
+  uv run pytest tests/server/test_oauth*.py -v
   ```
 
 **Interactive Testing (Manual browser login):**
@@ -149,18 +156,20 @@ OAuth integration tests support both **automated** (Playwright) and **interactiv
 - Example:
   ```bash
   # Run OAuth tests with interactive flow (will open browser and wait for manual login)
-  uv run pytest tests/integration/test_oauth_interactive.py -v
+  uv run pytest tests/client/test_oauth_interactive.py -v
   ```
 
 **Test Environment Setup:**
 - Start OAuth MCP server: `docker-compose up --build -d mcp-oauth`
 - OAuth server runs on port 8001 (regular MCP on 8000)
-- Both flows register OAuth clients dynamically using Nextcloud's OIDC provider
+- Shared OAuth client is registered once and reused across test runs
+- Client credentials cached in `.nextcloud_oauth_shared_test_client.json`
 
 **CI/CD Considerations:**
 - Interactive OAuth tests are automatically skipped when `GITHUB_ACTIONS` environment variable is set
 - Automated Playwright tests will run in CI/CD environments
 - Use Firefox browser in CI: `--browser firefox` (Chromium may have issues with localhost redirects)
+- Shared client approach reduces test time and API calls to Nextcloud
 
 ### Configuration Files