Move to tool/lib from test/lib.

tool/lib/find_executable.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+require "rbconfig"
+
+module EnvUtil
+  def find_executable(cmd, *args)
+    exts = RbConfig::CONFIG["EXECUTABLE_EXTS"].split | [RbConfig::CONFIG["EXEEXT"]]
+    ENV["PATH"].split(File::PATH_SEPARATOR).each do |path|
+      next if path.empty?
+      path = File.join(path, cmd)
+      exts.each do |ext|
+        cmdline = [path + ext, *args]
+        begin
+          return cmdline if yield(IO.popen(cmdline, "r", err: [:child, :out], &:read))
+        rescue
+          next
+        end
+      end
+    end
+    nil
+  end
+  module_function :find_executable
+end