flake.nix: create packaging, generate coverage

nix/coverage.nix

@@ -0,0 +1,75 @@
+{
+  lib
+, stdenvNoCC
+, rustPlatform
+, cargoToml
+, cargoLock
+, src
+
+, rust-bin
+, cargo-nextest
+, grcov
+}:
+
+stdenvNoCC.mkDerivation {
+  pname = "coverage-${cargoToml.package.name}";
+  version = cargoToml.package.version;
+  inherit src;
+
+  env = {
+    RUSTFLAGS = "-Cinstrument-coverage";
+    LLVM_PROFILE_FILE = "target/coverage/%p-%m.profraw";
+  };
+
+  cargoDeps = rustPlatform.importCargoLock {
+    lockFile = cargoLock;
+  };
+
+  nativeBuildInputs = [
+    rustPlatform.cargoSetupHook
+    cargo-nextest
+    grcov
+    (rust-bin.selectLatestNightlyWith (toolchain: toolchain.default.override {
+      extensions = [ "llvm-tools-preview" ];
+    }))
+  ];
+
+  buildPhase = ''
+    runHook preBuild
+
+    export HOME="$(pwd)"
+
+    cargo nextest run --all-features --release --no-fail-fast
+
+    grcov \
+      --source-dir . \
+      --binary-path ./target/release/deps/ \
+      --excl-start 'mod test* \{' \
+      --ignore 'tests/*' \
+      --ignore "*test.rs" \
+      --ignore "*tests.rs" \
+      --ignore "*github.com*" \
+      --ignore "*libcore*" \
+      --ignore "*rustc*" \
+      --ignore "*liballoc*" \
+      --ignore "*cargo*" \
+      -t html \
+      -o ./target/coverage/html \
+      target/coverage/
+
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preBuild
+
+    mv target/coverage $out
+
+    runHook postBuild
+  '';
+
+  meta = with lib; {
+    license = licenses.mit;
+    platforms = platforms.linux ++ platforms.darwin;
+  };
+}

nix/default.nix

@@ -0,0 +1,22 @@
+{
+  lib
+, rustPlatform
+, cargoToml
+, cargoLock
+, src
+}:
+let
+in
+rustPlatform.buildRustPackage {
+  pname = cargoToml.package.name;
+  version = cargoToml.package.version;
+  inherit src;
+
+  cargoLock.lockFile = cargoLock;
+
+  meta = with lib; {
+    license = licenses.mit;
+    platforms = platforms.linux ++ platforms.darwin;
+    mainProgram = (lib.head cargoToml.bin).name;
+  };
+}