Add enable_parallel and disable_parallel.

examples/failures.rb

@@ -31,7 +31,7 @@ def test_another_test_yes
   end
 
   def test_inc_test
-    assert_includes %w[a b c], 'd'
+    assert_include %w[a b c], 'd'
   end
 
   def test_equal

examples/parallel.rb

@@ -0,0 +1,15 @@
+require File.expand_path('../../lib/para', __FILE__)
+
+class Foo < Para::Test
+  enable_parallel
+
+  test "foo" do
+    assert true
+    sleep 1
+  end
+
+  test "foo again" do
+    assert true
+    sleep 1
+  end
+end

lib/para/base.rb

@@ -6,14 +6,31 @@ def thread_count()    (ENV['THREADS'] || 1).to_i; end
     def printer()         @printer ||= Printer.new; end
 
     # Worker
-    def worker!(q, i)     while q.any?; run_test i, *q.shift; end; end
+    def worker!(q, i)
+      if i == 0
+        # For the first thread, just take the next test.
+        while q.any?
+          run_test i, *q.shift
+        end
+      else
+        # For other threads, only work on the ones that are enabled for parallel.
+        while true
+          test = q.detect { |(testcase, _)| testcase.parallel? } or break
+          q.delete test
+          run_test i, *test
+        end
+      end
+    end
 
     # Spawn multiple threads, each doing #work!
     def start!
       Signal.trap("INT") { printer.done; exit }
 
       queue = Test.all_tests
-      thread_count.times.map { |i| Thread.new { worker!(queue, i) } }.each { |t| t.join }
+      threads = (thread_count-1).times.map { |i| Thread.new { worker!(queue, i+1) } }
+
+      worker!(queue, 0)
+      threads.join
 
       printer.done
     end
@@ -46,6 +63,10 @@ def failures()          @failures ||= Array.new; end
     def teardown(); end
     def setup(); end
 
+    def self.enable_parallel()  @parallel = true; end
+    def self.disable_parallel() @parallel = false; end
+    def self.parallel?()        !! @parallel; end
+
     def assert(what, msg=nil)
       if what
         @runner.printer.success