1 files changed, 126 insertions, 0 deletions
diff --git a/test/test_prime.rb b/test/test_prime.rb
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+++ b/test/test_prime.rb
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+require 'test/unit'
+require 'prime'
+require 'stringio'
+
+class TestPrime < Test::Unit::TestCase
+  # The first 100 prime numbers
+  PRIMES = [
+    2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37,
+    41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 
+    89, 97, 101, 103, 107, 109, 113, 127, 131, 
+    137, 139, 149, 151, 157, 163, 167, 173, 179, 
+    181, 191, 193, 197, 199, 211, 223, 227, 229, 
+    233, 239, 241, 251, 257, 263, 269, 271, 277, 
+    281, 283, 293, 307, 311, 313, 317, 331, 337, 
+    347, 349, 353, 359, 367, 373, 379, 383, 389, 
+    397, 401, 409, 419, 421, 431, 433, 439, 443, 
+    449, 457, 461, 463, 467, 479, 487, 491, 499, 
+    503, 509, 521, 523, 541,
+  ]
+  def test_each
+    primes = []
+    Prime.each do |p|
+      break if p > 541
+      primes << p
+    end
+    assert_equal PRIMES, primes
+  end
+
+  def test_each_by_prime_number_theorem
+    3.upto(15) do |i|
+      max = 2**i
+      primes = []
+      Prime.each do |p|
+        break if p >= max
+        primes << p
+      end
+
+      # Prime number theorem
+      assert primes.length >= max/Math.log(max)  
+      delta = 0.05
+      li = (2..max).step(delta).inject(0){|sum,x| sum + delta/Math.log(x)}
+      assert primes.length <= li
+    end
+  end
+
+  def test_each_without_block
+    enum = Prime.each
+    assert enum.respond_to?(:each)
+    assert enum.kind_of?(Enumerable)
+    assert enum.respond_to?(:with_index)
+    assert enum.respond_to?(:next)
+    assert enum.respond_to?(:succ)
+    assert enum.respond_to?(:rewind)
+  end
+
+  def test_new
+    buf = StringIO.new('', 'w')
+    orig, $stderr = $stderr, buf
+
+    enum = Prime.new
+    assert !buf.string.empty?
+    $stderr = orig
+
+    assert enum.respond_to?(:each)
+    assert enum.kind_of?(Enumerable)
+    assert enum.respond_to?(:succ)
+
+    assert Prime === enum
+  ensure
+    $stderr = orig
+  end
+
+  def test_enumerator_succ
+    enum = Prime.each
+    assert_equal PRIMES[0, 50], 50.times.map{ enum.succ }
+    assert_equal PRIMES[50, 50], 50.times.map{ enum.succ }
+    enum.rewind
+    assert_equal PRIMES[0, 100], 100.times.map{ enum.succ }
+  end
+
+  def test_enumerator_with_index
+    enum = Prime.each
+    last = -1
+    enum.with_index do |p,i|
+      break if i >= 100
+      assert_equal last+1, i
+      assert_equal PRIMES[i], p
+      last = i
+    end
+  end
+
+  class TestInteger < Test::Unit::TestCase
+    def test_prime_division
+      pd = PRIMES.inject(&:*).prime_division
+      assert_equal PRIMES.map{|p| [p, 1]}, pd
+    end
+
+    def test_from_prime_division
+      assert_equal PRIMES.inject(&:*), Integer.from_prime_division(PRIMES.map{|p| [p,1]})
+    end
+
+    def test_prime?
+      # small primes
+      assert 2.prime?
+      assert 3.prime?
+
+      # squared prime
+      assert !4.prime?
+      assert !9.prime?
+
+      # mersenne numbers
+      assert (2**31-1).prime?
+      assert !(2**32-1).prime?
+
+      # fermat numbers
+      assert (2**(2**4)+1).prime?
+      assert !(2**(2**5)+1).prime? # Euler!
+
+      # large composite
+      assert !((2**13-1) * (2**17-1)).prime?
+
+      # factorial
+      assert !(2...100).inject(&:*).prime?
+    end
+  end
+end