summaryrefslogtreecommitdiff
path: root/spec/ruby/library/prime/integer/prime_spec.rb
diff options
context:
space:
mode:
Diffstat (limited to 'spec/ruby/library/prime/integer/prime_spec.rb')
-rw-r--r--spec/ruby/library/prime/integer/prime_spec.rb17
1 files changed, 17 insertions, 0 deletions
diff --git a/spec/ruby/library/prime/integer/prime_spec.rb b/spec/ruby/library/prime/integer/prime_spec.rb
new file mode 100644
index 0000000000..d24f883b19
--- /dev/null
+++ b/spec/ruby/library/prime/integer/prime_spec.rb
@@ -0,0 +1,17 @@
+require_relative '../../../spec_helper'
+require 'prime'
+
+describe "Integer#prime?" do
+ it "returns a true value for prime numbers" do
+ 2.prime?.should == true
+ 3.prime?.should == true
+ (2**31-1).prime?.should == true # 8th Mersenne prime (M8)
+ end
+
+ it "returns a false value for composite numbers" do
+ 4.prime?.should == false
+ 15.prime?.should == false
+ (2**32-1).prime?.should == false
+ ( (2**17-1)*(2**19-1) ).prime?.should == false # M6*M7
+ end
+end