1 files changed, 29 insertions, 16 deletions

diff --git a/spec/ruby/core/process/groups_spec.rb b/spec/ruby/core/process/groups_spec.rb
index 0669258bf3..fa916671a4 100644
--- a/spec/ruby/core/process/groups_spec.rb
+++ b/spec/ruby/core/process/groups_spec.rb
@@ -1,26 +1,37 @@
-require File.expand_path('../../../spec_helper', __FILE__)
+require_relative '../../spec_helper'
 
 describe "Process.groups" do
   platform_is_not :windows do
     it "gets an Array of the gids of groups in the supplemental group access list" do
       groups = `id -G`.scan(/\d+/).map { |i| i.to_i }
+      # Include the standard `id` command output.  On macOS, GNU
+      # coreutils `id` is limited to NGROUPS_MAX groups, because of
+      # the backward compatibility of getgroups(2).
+      (groups |= `/usr/bin/id -G`.scan(/\d+/).map { |i| i.to_i }) rescue nil
       gid = Process.gid
 
-      expected = (groups.sort - [gid]).sort
-      actual = (Process.groups - [gid]).sort
+      expected = (groups.sort - [gid]).uniq.sort
+      actual = (Process.groups - [gid]).uniq.sort
       actual.should == expected
     end
+  end
+end
 
-    # NOTE: This is kind of sketchy.
-    it "sets the list of gids of groups in the supplemental group access list" do
-      groups = Process.groups
-      if Process.uid == 0
+describe "Process.groups=" do
+  platform_is_not :windows, :android do
+    as_superuser do
+      it "sets the list of gids of groups in the supplemental group access list" do
+        groups = Process.groups
         Process.groups = []
         Process.groups.should == []
         Process.groups = groups
         Process.groups.sort.should == groups.sort
-      else
-        platform_is :aix do
+      end
+    end
+
+    as_user do
+      platform_is :aix do
+        it "sets the list of gids of groups in the supplemental group access list" do
           # setgroups() is not part of the POSIX standard,
           # so its behavior varies from OS to OS.  AIX allows a non-root
           # process to set the supplementary group IDs, as long as
@@ -30,6 +41,7 @@ describe "Process.groups" do
           # it should no longer be able to set any supplementary
           # group IDs, even if it originally belonged to them.
           # It should only be able to set its primary group ID.
+          groups = Process.groups
           Process.groups = groups
           Process.groups.sort.should == groups.sort
           Process.groups = []
@@ -38,17 +50,18 @@ describe "Process.groups" do
           Process.groups.should == [ Process.gid ]
           supplementary = groups - [ Process.gid ]
           if supplementary.length > 0
-            lambda { Process.groups = supplementary }.should raise_error(Errno::EPERM)
+            -> { Process.groups = supplementary }.should.raise(Errno::EPERM)
           end
         end
-        platform_is_not :aix do
-          lambda { Process.groups = [] }.should raise_error(Errno::EPERM)
+      end
+
+      platform_is_not :aix do
+        it "raises Errno::EPERM" do
+          -> {
+            Process.groups = [0]
+          }.should.raise(Errno::EPERM)
         end
       end
     end
   end
 end
-
-describe "Process.groups=" do
-  it "needs to be reviewed for spec completeness"
-end