Run table and unit table

.github/workflows/test_file_reader.yml

@@ -28,6 +28,7 @@ jobs:
         python -m pip install --upgrade pip
         pip install -r requirements.txt
         pip install .  
+        pip install graphviz
     - name: Test reader
       run: |
         pip install pytest

.github/workflows/test_file_writer.yml

@@ -26,7 +26,10 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install -r requirements.txt
-        pip install .  
+        python -m pip install opencv-python
+        pip install .
+        pip install graphviz
+        sudo apt-get install graphviz
     - name: Test reader
       run: |
         pip install pytest

dsi/backends/parquet.py

@@ -1,7 +1,5 @@
 import pyarrow as pa
 from pyarrow import parquet as pq
-import nbconvert as nbc
-import nbformat as nbf
 import subprocess
 
 from dsi.backends.filesystem import Filesystem
@@ -46,6 +44,9 @@ def get_cmd_output(cmd: list) -> str:
         return proc.stdout.strip().decode("utf-8")
 
     def inspect_artifacts(self, collection, interactive=False):
+        import nbconvert as nbc
+        import nbformat as nbf
+
         """Populate a Jupyter notebook with tools required to look at Parquet data."""
         nb = nbf.v4.new_notebook()
         text = """\