* lib/prime.rb: Add basic argument checking to Prime.prime?

[Bug #11606]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52201 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Tue Oct 20 12:17:56 2015  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
+
+	* lib/prime.rb: Add basic argument checking to Prime.prime?
+	    [Bug #11606]
+
 Tue Oct 20 12:17:50 2015  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
 
 	* lib/prime.rb: Optimize Integer#prime?

lib/prime.rb

@@ -144,6 +144,8 @@ class Prime
   # +value+:: an arbitrary integer to be checked.
   # +generator+:: optional. A pseudo-prime generator.
   def prime?(value, generator = Prime::Generator23.new)
+    raise ArgumentError, "Expected a prime generator, got #{generator}" unless generator.respond_to? :each
+    raise ArgumentError, "Expected an integer, got #{value}" unless value.respond_to?(:integer?) && value.integer?
     return false if value < 2
     generator.each do |num|
       q,r = value.divmod num

test/test_prime.rb

@@ -118,6 +118,11 @@ class TestPrime < Test::Unit::TestCase
     assert_not_respond_to(Prime.instance, :next)
   end
 
+  def test_prime_each_basic_argument_checking
+    assert_raise(ArgumentError) { Prime.prime?(1,2) }
+    assert_raise(ArgumentError) { Prime.prime?(1.2) }
+  end
+
   class TestInteger < Test::Unit::TestCase
     def test_prime_division
       pd = PRIMES.inject(&:*).prime_division