diff options
| -rw-r--r-- | lib/prime.rb | 12 | ||||
| -rw-r--r-- | test/test_prime.rb | 8 |
2 files changed, 20 insertions, 0 deletions
diff --git a/lib/prime.rb b/lib/prime.rb index 5be12f24f5..44129d2dd7 100644 --- a/lib/prime.rb +++ b/lib/prime.rb @@ -141,6 +141,18 @@ class Prime generator.each(&block) end + # Return true if +obj+ is an Integer an is prime. Also returns + # true if +obj+ is a Module that is an ancestor of +Prime+. + def include?(obj) + case obj + when Integer + prime?(obj) + when Module + Module.instance_method(:include?).bind(Prime).call(obj) + else + false + end + end # Returns true if +value+ is a prime number, else returns false. # diff --git a/test/test_prime.rb b/test/test_prime.rb index 9db13f08fe..b809d15df7 100644 --- a/test/test_prime.rb +++ b/test/test_prime.rb @@ -27,6 +27,14 @@ class TestPrime < Test::Unit::TestCase assert_equal PRIMES, primes end + def test_include? + assert_equal(false, Prime.include?(nil)) + assert_equal(true, Prime.include?(3)) + assert_equal(false, Prime.include?(4)) + assert_equal(true, Prime.include?(Enumerable)) + assert_equal(false, Prime.include?(Comparable)) + end + def test_integer_each_prime primes = [] Integer.each_prime(1000) do |p| |