Only add pydicom handler if not present (#50)

Author: scaramallion

.github/workflows/pytest-builds.yml

@@ -4,7 +4,6 @@ on:
   push:
     branches: [ master ]
   pull_request:
-    branches: [ master ]
 
 jobs:
   ubuntu:
@@ -29,12 +28,17 @@ jobs:
         python -m pip install .
         python -m pip uninstall -y pylibjpeg-openjpeg
         python -m pip install git+https://github.com/pydicom/pylibjpeg-data
-        python -m pip install pytest coverage pytest-cov pydicom
+        python -m pip install pytest coverage pytest-cov
 
     - name: Run pytest with no plugins
       run: |
         pytest --cov=pylibjpeg --cov-append
 
+    - name: Rerun pytest with pydicom and no plugins
+      run: |
+        pip install pydicom
+        pytest --cov=pylibjpeg --cov-append
+
     - name: Rerun pytest with -lj plugin
       run: |
 

pylibjpeg/__init__.py

@@ -27,8 +27,14 @@ def debug_logger():
 
 try:
     import pydicom
-    add_handler()
     _logger.debug('pydicom module loaded')
     from pylibjpeg.pydicom.utils import generate_frames
+
+    # We only add a handler if pydicom doesn't already have one
+    try:
+        import pydicom.pixel_data_handlers.pylibjpeg_handler
+    except ImportError:
+        add_handler()
+
 except ImportError:
     pass

pylibjpeg/tests/test_pydicom.py

@@ -72,6 +72,7 @@ def test_get_pixeldata_no_lj_syntax(self):
             handler.get_pixeldata(ds)
 
 
+@pytest.mark.skipif(not HAS_PYDICOM, reason="No pydicom")
 class TestPlugins(object):
     """Test interaction with plugins."""
     @pytest.mark.skipif(not RUN_JPEG, reason="No JPEG plugin")