Rename tests dir from 'internal' to 'custom'

Author: AlePouroullis

.fernignore

@@ -18,7 +18,7 @@ src/humanloop/cli
 
 ## Tests
 
-tests/internal
+tests/custom
 
 ## CI
 

.gitignore

@@ -5,5 +5,6 @@ poetry.toml
 .ruff_cache/
 .vscode
 .env
+.env.test
 tests/assets/*.jsonl
 tests/assets/*.parquet

tests/custom/README.md

@@ -0,0 +1,19 @@
+# Custom Tests Directory
+
+This directory contains custom tests for the Humanloop Python SDK. While the main SDK is auto-generated using [Fern](https://buildwithfern.com/), this directory allows us to add our own test implementations that won't be overwritten during regeneration.
+
+## Why Custom Tests?
+
+- **Preservation**: Tests in this directory won't be overwritten when regenerating the SDK
+- **Custom Implementation**: Allows testing of our own implementations beyond the auto-generated code
+- **Integration**: Enables testing of how our custom code works with the auto-generated SDK
+
+## Running Tests
+
+```bash
+# Run all custom tests
+pytest tests/custom/
+
+# Run specific test file
+pytest tests/custom/sync/test_sync_client.py
+```

tests/custom/integration/test_evals.py

@@ -4,7 +4,7 @@
 import pytest
 from humanloop.client import Humanloop
 from humanloop.error import HumanloopRuntimeError
-from tests.integration.conftest import TestIdentifiers
+from tests.custom.integration.conftest import TestIdentifiers
 
 
 def test_eval_run_works_on_online_files(