Add default.nix to build and test the crate

Author: danieldk

default.nix

@@ -0,0 +1,62 @@
+{
+  callPackage
+, stdenv
+
+, defaultCrateOverrides
+, nix-gitignore
+
+, darwin
+, python3Packages
+, pkgconfig
+
+, releaseBuild ? true
+}:
+
+let
+  rustNightly = callPackage ./nix/rust-nightly.nix {};
+in ((callPackage ./nix/finalfusion-python.nix {}).finalfusion_python {}).override {
+  release = releaseBuild;
+  rust = rustNightly;
+
+  crateOverrides = defaultCrateOverrides // {
+    finalfusion-python = attr: rec {
+      pname = "finalfusion-python";
+      name = "${pname}-${attr.version}";
+
+      src = nix-gitignore.gitignoreSource [ ".git/" "*.nix" "/nix" ] ./.;
+
+      buildInputs = stdenv.lib.optional stdenv.isDarwin darwin.Security;
+
+      installCheckInputs = [ python3Packages.pytest ];
+
+      propagatedBuildInputs = [ python3Packages.numpy ];
+
+      doInstallCheck = true;
+
+      installPhase = let
+        sitePackages = python3Packages.python.sitePackages;
+        sharedLibrary = stdenv.hostPlatform.extensions.sharedLibrary;
+      in ''
+        mkdir -p "$out/${sitePackages}"
+        cp target/lib/libfinalfusion-*${sharedLibrary} \
+          "$out/${sitePackages}/finalfusion.so"
+        export PYTHONPATH="$out/${sitePackages}:$PYTHONPATH"
+      '';
+
+      installCheckPhase = ''
+        cargo fmt --all -- --check
+        pytest
+      '';
+
+      meta = with stdenv.lib; {
+        description = "Python module for finalfusion embeddings";
+        license = licenses.asl20;
+        platforms = platforms.all;
+      };
+    };
+
+    pyo3 = attr: {
+      buildInputs = [ python3Packages.python ];
+    };
+  };
+}