diff --git a/speedcopy/__init__.py b/speedcopy/__init__.py
index c7b2c99..e681fd7 100644
--- a/speedcopy/__init__.py
+++ b/speedcopy/__init__.py
@@ -144,8 +144,8 @@ if not sys.platform.startswith("win32"):
             os.symlink(os.readlink(src), dst)
         else:
             fs_src_type = FilesystemInfo().filesystem(src.encode('utf-8'))
-            fs_dst_type = FilesystemInfo().filesystem(
-                os.path.dirname(dst.encode('utf-8')))
+            dst_dir_path = os.path.normpath(os.path.dirname(dst.encode('utf-8')))  # noqa: E501
+            fs_dst_type = FilesystemInfo().filesystem(dst_dir_path)
             supported_fs = ['CIFS', 'SMB2']
             debug(">>> Source FS: {}".format(fs_src_type))
             debug(">>> Destination FS: {}".format(fs_dst_type))
@@ -218,8 +218,8 @@ else:
                                  ctypes.c_void_p)
             copyfile.restype = ctypes.HRESULT
 
-            source_file = os.path.normpath(src)
-            dest_file = os.path.normpath(dst)
+            source_file = os.path.abspath(os.path.normpath(src))
+            dest_file = os.path.abspath(os.path.normpath(dst))
             if source_file.startswith('\\\\'):
                 source_file = 'UNC\\' + source_file[2:]
             if dest_file.startswith('\\\\'):

Copying doesn't work if non-absolute filenames supplied
```
speedcopy.copyfile("C:/Temp/asdf", "C:/Temp/fdsa")
```
should work exactly the same as
```
os.chdir("C:/Temp")
speedcopy.copyfile("asdf", "fdsa")
```

diff --git a/tests/test_speedcopy.py b/tests/test_speedcopy.py
index bea8ba4..ec69756 100644
--- a/tests/test_speedcopy.py
+++ b/tests/test_speedcopy.py
@@ -3,6 +3,7 @@ import speedcopy
 import os
 
 speedcopy.SPEEDCOPY_DEBUG = True
+_FILE_SIZE = 5 * 1024 * 1024
 
 
 def setup_function(function):
@@ -13,11 +14,11 @@ def teadown_function(function):
     speedcopy.unpatch_copyfile()
 
 
-def test_copy(tmpdir):
+def test_copy_abs(tmpdir):
     src = tmpdir.join("source")
     dst = tmpdir.join("destination")
     with open(str(src), "wb") as f:
-        f.write(os.urandom(5 * 1024 * 1024))
+        f.write(os.urandom(_FILE_SIZE))
     f.close()
 
     shutil.copyfile(str(src), str(dst))
@@ -25,6 +26,24 @@ def test_copy(tmpdir):
     assert os.path.isfile(str(dst))
 
 
+def test_copy_rel(tmpdir):
+    cwd = os.getcwd()
+    os.chdir(str(tmpdir))
+
+    try:
+        src = "source"
+        dst = "destination"
+        with open(str(src), "wb") as f:
+            f.write(os.urandom(_FILE_SIZE))
+        f.close()
+
+        shutil.copyfile(str(src), str(dst))
+
+        assert os.path.isfile(str(dst))
+    finally:
+        os.chdir(cwd)
+
+
 def test_patch():
     assert shutil.copyfile == speedcopy.copyfile
 

pip install -e .
parse_log_pytest
pytest
pysendfile pytest
apt-get update apt-get install -y gcc
3.6
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
attrs @ file:///opt/conda/conda-bld/attrs_1642510447205/work
certifi==2021.5.30
importlib-metadata @ file:///tmp/build/80754af9/importlib-metadata_1631916693255/work
iniconfig @ file:///home/linux1/recipes/ci/iniconfig_1610983019677/work
more-itertools @ file:///tmp/build/80754af9/more-itertools_1637733554872/work
packaging @ file:///tmp/build/80754af9/packaging_1637314298585/work
pluggy @ file:///tmp/build/80754af9/pluggy_1615976315926/work
py @ file:///opt/conda/conda-bld/py_1644396412707/work
pyparsing @ file:///tmp/build/80754af9/pyparsing_1635766073266/work
pysendfile==2.0.1
pytest==6.2.4
-e git+https://github.com/antirotor/speedcopy.git@78dee74fa0f0aef2c61f9f48f6389969f63272f7#egg=speedcopy
toml @ file:///tmp/build/80754af9/toml_1616166611790/work
typing_extensions @ file:///opt/conda/conda-bld/typing_extensions_1647553014482/work
zipp @ file:///tmp/build/80754af9/zipp_1633618647012/work

name: speedcopy
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - attrs=21.4.0=pyhd3eb1b0_0
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2021.5.30=py36h06a4308_0
  - importlib-metadata=4.8.1=py36h06a4308_0
  - importlib_metadata=4.8.1=hd3eb1b0_0
  - iniconfig=1.1.1=pyhd3eb1b0_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.3=he6710b0_2
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - more-itertools=8.12.0=pyhd3eb1b0_0
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - packaging=21.3=pyhd3eb1b0_0
  - pip=21.2.2=py36h06a4308_0
  - pluggy=0.13.1=py36h06a4308_0
  - py=1.11.0=pyhd3eb1b0_0
  - pyparsing=3.0.4=pyhd3eb1b0_0
  - pytest=6.2.4=py36h06a4308_2
  - python=3.6.13=h12debd9_1
  - readline=8.2=h5eee18b_0
  - setuptools=58.0.4=py36h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - toml=0.10.2=pyhd3eb1b0_0
  - typing_extensions=4.1.1=pyh06a4308_0
  - wheel=0.37.1=pyhd3eb1b0_0
  - xz=5.6.4=h5eee18b_1
  - zipp=3.6.0=pyhd3eb1b0_0
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - pysendfile==2.0.1
prefix: /opt/conda/envs/speedcopy

tests/test_speedcopy.py::test_copy_rel
tests/test_speedcopy.py::test_copy_abs tests/test_speedcopy.py::test_patch tests/test_speedcopy.py::test_unpatch
speedcopy/__init__.py
speedcopy/__init__.py