* lib/prime.rb: Optimize prime?

  Adapted from patch by Jabari Zakiya [#12665]

* test/test_prime.rb: Improve test

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55856 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 10 deletions

diff --git a/test/test_prime.rb b/test/test_prime.rb
index b48ccae319..7f15894abf 100644
--- a/test/test_prime.rb
+++ b/test/test_prime.rb
@@ -140,17 +140,14 @@ class TestPrime < Test::Unit::TestCase
     end
 
     def test_prime?
-      # zero and unit
-      assert_not_predicate(0, :prime?)
-      assert_not_predicate(1, :prime?)
-
-      # small primes
-      assert_predicate(2, :prime?)
-      assert_predicate(3, :prime?)
+      PRIMES.each do |p|
+        assert_predicate(p, :prime?)
+      end
 
-      # squared prime
-      assert_not_predicate(4, :prime?)
-      assert_not_predicate(9, :prime?)
+      composites = (0..PRIMES.last).to_a - PRIMES
+      composites.each do |c|
+        assert_not_predicate(c, :prime?)
+      end
 
       # mersenne numbers
       assert_predicate((2**31-1), :prime?)