To build a cargo project without extra tests, run the following in a fresh directory:

nix flake init -t github:ipetkov/crane#quick-start-simple

Alternatively, if you have an existing project already, copy and paste the following flake.nix:

{
  description = "Build a cargo project without extra checks";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";

    crane.url = "github:ipetkov/crane";

    flake-utils.url = "github:numtide/flake-utils";
  };

  outputs = { self, nixpkgs, crane, flake-utils, ... }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = nixpkgs.legacyPackages.${system};

        craneLib = crane.mkLib pkgs;

        # Common arguments can be set here to avoid repeating them later
        # Note: changes here will rebuild all dependency crates
        commonArgs = {
          src = craneLib.cleanCargoSource ./.;
          strictDeps = true;

          buildInputs = [
            # Add additional build inputs here
          ] ++ pkgs.lib.optionals pkgs.stdenv.isDarwin [
            # Additional darwin specific inputs can be set here
            pkgs.libiconv
          ];
        };

        my-crate = craneLib.buildPackage (commonArgs // {
          cargoArtifacts = craneLib.buildDepsOnly commonArgs;

          # Additional environment variables or build phases/hooks can be set
          # here *without* rebuilding all dependency crates
          # MY_CUSTOM_VAR = "some value";
        });
      in
      {
        checks = {
          inherit my-crate;
        };

        packages.default = my-crate;

        apps.default = flake-utils.lib.mkApp {
          drv = my-crate;
        };

        devShells.default = craneLib.devShell {
          # Inherit inputs from checks.
          checks = self.checks.${system};

          # Additional dev-shell environment variables can be set directly
          # MY_CUSTOM_DEVELOPMENT_VAR = "something else";

          # Extra inputs can be added here; cargo and rustc are provided by default.
          packages = [
            # pkgs.ripgrep
          ];
        };
      });
}