shunit2: use resholvePackage

pkgs/tools/misc/shunit2/default.nix

@@ -1,6 +1,15 @@
-{ lib, stdenv, fetchFromGitHub }:
+{ lib
+, resholvePackage
+, fetchFromGitHub
+, bash
+, coreutils
+, gnused
+, gnugrep
+, findutils
+, ncurses
+}:
 
-stdenv.mkDerivation {
+resholvePackage {
   pname = "shunit2";
   version = "2019-08-10";
 
@@ -22,6 +31,55 @@ stdenv.mkDerivation {
     $out/bin/shunit2
   '';
 
+  solutions = {
+    shunit = {
+      # Caution: see __SHUNIT_CMD_ECHO_ESC before changing
+      interpreter = "${bash}/bin/sh";
+      scripts = [ "bin/shunit2" ];
+      inputs = [ coreutils gnused gnugrep findutils ncurses ];
+      # resholve's Nix API is analogous to the CLI flags
+      # documented in 'man resholve'
+      fake = {
+        # "missing" functions shunit2 expects the user to declare
+        function = [
+          "oneTimeSetUp"
+          "oneTimeTearDown"
+          "setUp"
+          "tearDown"
+          "suite"
+          "noexec"
+        ];
+        # shunit2 is both bash and zsh compatible, and in
+        # some zsh-specific code it uses this non-bash builtin
+        builtin = [ "setopt" ];
+      };
+      fix = {
+        # stray absolute path; make it resolve from coreutils
+        "/usr/bin/od" = true;
+        /*
+        Caution: this one is contextually debatable. shunit2
+        sets this variable after testing whether `echo -e test`
+        yields `test` or `-e test`. Since we're setting the
+        interpreter, we can pre-test this. But if we go fiddle
+        the interpreter later, I guess we _could_ break it.
+        */
+        "$__SHUNIT_CMD_ECHO_ESC" = [ "'echo -e'" ];
+        "$SHUNIT_CMD_TPUT" = [ "tput" ]; # from ncurses
+      };
+      keep = {
+        # dynamically defined in shunit2:_shunit_mktempFunc
+        eval = [ "shunit_condition_" "_shunit_test_" "_shunit_prepForSourcing" ];
+
+        # dynamic based on CLI flag
+        "$_SHUNIT_LINENO_" = true;
+      };
+      execer = [
+        # drop after https://github.com/abathur/binlore/issues/2
+        "cannot:${ncurses}/bin/tput"
+      ];
+    };
+  };
+
   meta = with lib; {
     homepage = "https://github.com/kward/shunit2";
     description = "A xUnit based unit test framework for Bourne based shell scripts";