Add QLoRA Train and Merge16bit Test (#2130)

* add reference and unsloth lora merging tests

* add test / dataset printing to test scripts

* allow running tests from repo root

* add qlora test readme

* more readme edits

* ruff formatting

* additional readme comments

* forgot to add actual tests

* add apache license

tests/utils/__init__.py

@@ -0,0 +1,33 @@
+# Copyright 2023-present Daniel Han-Chen & the Unsloth team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import time
+from contextlib import contextmanager
+
+
+@contextmanager
+def timer(name):
+    start = time.time()
+    yield
+    end = time.time()
+    print(f"{name} took {end - start:.2f} seconds")
+
+
+@contextmanager
+def header_footer_context(title: str, char="-"):
+    print()
+    print(f"{char}" * 50 + f" {title} " + f"{char}" * 50)
+    yield
+    print(f"{char}" * (100 + len(title) + 2))
+    print()