diff --git a/gwsumm/archive.py b/gwsumm/archive.py
index ad9d4ae3..b2c6ac53 100644
--- a/gwsumm/archive.py
+++ b/gwsumm/archive.py
@@ -210,7 +210,8 @@ def read_data_archive(sourcefile, rm_source_on_fail=True):
     # down the whole workflow, requiring manual intervention. Here, we attempt
     # to automatically catch a common failure
     try:
-        h5file = File(sourcefile, 'r')
+        with File(sourcefile, 'r'):
+            pass
     except FileNotFoundError:
         raise
     except OSError as exc:  # file is corrupt, so we remove it to start fresh
@@ -250,7 +251,8 @@ def read_data_archive(sourcefile, rm_source_on_fail=True):
 
         # -- timeseries -------------------------
 
-        for dataset in h5file.get('timeseries', {}).values():
+        for name in h5file.get('timeseries', {}):
+            dataset = h5file['timeseries'][name]
             ts = TimeSeries.read(dataset, format='hdf5')
             if (re.search(r'\.(rms|min|mean|max|n)\Z', ts.channel.name) and
                     ts.sample_rate.value == 1.0):
@@ -271,7 +273,8 @@ def read_data_archive(sourcefile, rm_source_on_fail=True):
 
         # -- statevector -- ---------------------
 
-        for dataset in h5file.get('statevector', {}).values():
+        for name in h5file.get('statevector', {}):
+            dataset = h5file['statevector'][name]
             sv = StateVector.read(dataset, format='hdf5')
             sv.channel = get_channel(sv.channel)
             add_timeseries(sv, key=sv.channel.ndsname)
@@ -279,9 +282,11 @@ def read_data_archive(sourcefile, rm_source_on_fail=True):
         # -- spectrogram ------------------------
 
         for tag, add_ in zip(
-                ['spectrogram', 'coherence-components'],
-                [add_spectrogram, add_coherence_component_spectrogram]):
-            for key, dataset in h5file.get(tag, {}).items():
+            ['spectrogram', 'coherence-components'],
+            [add_spectrogram, add_coherence_component_spectrogram],
+        ):
+            for key in h5file.get(tag, {}):
+                dataset = h5file[tag][key]
                 key = key.rsplit(',', 1)[0]
                 spec = Spectrogram.read(dataset, format='hdf5')
                 spec.channel = get_channel(spec.channel)
@@ -289,14 +294,16 @@ def read_data_archive(sourcefile, rm_source_on_fail=True):
 
         # -- segments ---------------------------
 
-        for name, dataset in h5file.get('segments', {}).items():
+        for name in h5file.get('segments', {}):
+            dataset = h5file['segments'][name]
             dqflag = DataQualityFlag.read(h5file, path=dataset.name,
                                           format='hdf5')
             globalv.SEGMENTS += {name: dqflag}
 
         # -- triggers ---------------------------
 
-        for dataset in h5file.get('triggers', {}).values():
+        for name in h5file.get('triggers', {}):
+            dataset = h5file['triggers'][name]
             load_table(dataset)
 
 
diff --git a/gwsumm/data/timeseries.py b/gwsumm/data/timeseries.py
index 6d03ac0e..54f12102 100644
--- a/gwsumm/data/timeseries.py
+++ b/gwsumm/data/timeseries.py
@@ -393,10 +393,12 @@ def all_adc(cache):
     """
     for path in cache:
         try:
-            tag = os.path.basename(path).split('-')[1]
+            path = os.path.basename(path)
         except (AttributeError, TypeError):  # CacheEntry
             tag = path.description
             path = path.path
+        else:
+            tag = path.split('-')[1]
         if not path.endswith('.gwf') or tag not in ADC_TYPES:
             return False
     return True
@@ -711,8 +713,11 @@ def _get_timeseries_dict(channels, segments, config=None,
                     data.override_unit(channel.unit)
 
                 # update channel type for trends
-                if data.channel.type is None and (
-                        data.channel.trend is not None):
+                if (
+                    data.channel is not None
+                    and data.channel.type is None
+                    and data.channel.trend is not None
+                ):
                     if data.dt.to('s').value == 1:
                         data.channel.type = 's-trend'
                     elif data.dt.to('s').value == 60:
diff --git a/gwsumm/tests/test_config.py b/gwsumm/tests/test_config.py
index 7d19ba82..d7d442f9 100644
--- a/gwsumm/tests/test_config.py
+++ b/gwsumm/tests/test_config.py
@@ -73,8 +73,8 @@ def new(cls):
         TEST_CONFIG.seek(0)
         return cp
 
+    @pytest.fixture
     @classmethod
-    @pytest.fixture()
     def cnfg(cls):
         return cls.new()
 
diff --git a/gwsumm/tests/test_plot.py b/gwsumm/tests/test_plot.py
index e59a469d..a5099f60 100644
--- a/gwsumm/tests/test_plot.py
+++ b/gwsumm/tests/test_plot.py
@@ -103,8 +103,8 @@ def create(cls, *args, **kwargs):
             return cls.PLOT(*args, **kwargs)
         return cls.PLOT(*cls.DEFAULT_ARGS, **cls.DEFAULT_KWARGS)
 
+    @pytest.fixture
     @classmethod
-    @pytest.fixture()
     def plot(cls):
         return cls.create()