Migrate testing of example notebooks to nix and run them in CI on the…

… dedicated GPU box

.github/workflows/build-with-nix.yml

@@ -39,3 +39,6 @@ jobs:
     - name: Test pytket-cutensornet
       # impure is necessary due to nixgl usage (system-dependent cuda)
       run: nix run .#tests --impure --accept-flake-config
+    - name: Test example notebooks
+      # impure is necessary due to nixgl usage (system-dependent cuda)
+      run: nix run .#example-tests --impure --accept-flake-config

examples/check-examples

@@ -10,6 +10,11 @@ do
     cmp ${name}.ipynb ${name}-gen.ipynb
     rm ${name}-gen.ipynb
 
-    # Run script:
-    python python/${name}.py
+    # run tests are performed in nix, allowing
+    # us to manage the testing environment in a
+    # reproducible way.
+    #
+    # See /nix-support/pytket-cutensornet.nix,
+    # in the derivation called
+    # run-pytket-cutensornet-examples.
 done

flake.nix

@@ -43,9 +43,9 @@
       in {
         packages = {
           default = pkgs.pytket-cutensornet;
-          cupy = pkgs.cupy';
           pytket-cutensornet = pkgs.pytket-cutensornet;
           tests = pkgs.run-pytket-cutensornet-tests;
+          example-tests = pkgs.run-pytket-cutensornet-examples;
         };
         devShells = {
           default = pkgs.mkShell { buildInputs = [ pkgs.pytket-cutensornet ]; };

nix-support/pytket-cutensornet.nix

@@ -65,4 +65,32 @@ EOF
       export LD_LIBRARY_PATH;
       ${test-env}/bin/pytest -s ${../tests};
   '';
+  run-pytket-cutensornet-examples = let
+    example-env = super.python3.withPackages(ps: with ps; [
+      self.pytket-cutensornet
+      matplotlib
+      numpy
+      networkx
+      ipython
+      nbmake
+      pytest
+    ]);
+    nixgl-bin = self.lib.getExe self.nixgl.auto.nixGLNvidia;
+  in super.writeShellScriptBin "run-pytket-cutensornet-examples" ''
+      HOME=$(mktemp -d);
+      export HOME;
+      NIXGL_PATH="$(${nixgl-bin} printenv LD_LIBRARY_PATH)";
+      WSL_PATH="/usr/lib/wsl/lib";
+      LD_LIBRARY_PATH="$NIXGL_PATH:$WSL_PATH:$LD_LIBRARY_PATH";
+      
+      example_dir=${../examples};
+      set -e;
+      for name in `cat ''${example_dir}/ci-tested-notebooks.txt`;
+      do
+          ${example-env}/bin/pytest \
+            --nbmake \
+            -p no:cacheprovider \
+            $example_dir/$name.ipynb;
+      done;
+  '';
 }