Avoid setting ENV["PATH"] in cmdtest itself.

Instead set PATH in the shell scripts used to execute
the actual commands to test.

bin/cmdtest.rb

@@ -190,13 +190,6 @@ module Cmdtest
       @orig_env_path.dup
     end
 
-    def set_env_path(path_arr)
-      path_str = path_arr.join(_path_separator)
-      if path_str != ENV["PATH"]
-        ENV["PATH"] = path_str
-      end
-    end
-
     def run
       @orig_cwd = Dir.pwd
       ENV["PATH"] = Dir.pwd + _path_separator + ENV["PATH"]

lib/cmdtest/testcase.rb

@@ -521,9 +521,8 @@ module Cmdtest
 
       @_runner.notify("cmdline", @_cmdline, @_comment_str)
       @_comment_str = nil
-      @_runner.set_env_path(@_env_path)
       @_t1 = Time.now
-      @_effects = @_work_dir.run_cmd(@_cmdline)
+      @_effects = @_work_dir.run_cmd(@_cmdline, @_env_path)
       @_t2 = Time.now
 
       @_checked_status = false

lib/cmdtest/workdir.rb

@@ -90,6 +90,14 @@ module Cmdtest
       File.join(Workdir.tmp_cmdtest_dir, "tmp-stderr.log")
     end
 
+    def _set_env_path_str(env_path)
+      if _windows
+        "set path=" + env_path.join(";")
+      else
+        "export PATH=" + env_path.join(":")
+      end
+    end
+
     def _ruby_S(cmdline)
       if @runner.opts.ruby_s
         if cmdline =~ /ruby/
@@ -102,8 +110,9 @@ module Cmdtest
       end
     end
 
-    def run_cmd(cmdline)
+    def run_cmd(cmdline, env_path)
       File.open(_tmp_command_sh, "w") do |f|
+        f.puts _set_env_path_str(env_path)
         f.puts _ruby_S(cmdline)
       end
       str = "%s %s  > %s  2> %s" % [