* Enumerator#size{=}: Basic generic specs

* Kernel#to_enum: Basic spec for block form
marcandre · Aug 18, 2010 · 43babf4 · 43babf4
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diff --git a/core/enumerator/fixtures/classes.rb b/core/enumerator/fixtures/classes.rb
@@ -0,0 +1,24 @@
+module EnumeratorSpecs
+
+  class Numerous
+    include Enumerable
+    def initialize(*list)
+      @list = list.empty? ? [2, 5, 3, 6, 1, 4] : list
+    end
+
+    def each
+      return to_enum unless block_given?
+      @list.each { |i| yield i }
+    end
+
+    def more(*list)
+      @list += list
+    end
+  end
+
+  class SizedNumerous < Numerous
+    def size
+      @list.size
+    end
+  end
+end
diff --git a/core/enumerator/size_spec.rb b/core/enumerator/size_spec.rb
@@ -0,0 +1,296 @@
+# encoding: utf-8
+
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+# Note: this describes the generic #size and #size=
+# Specialized #size methods are found in subfolders, e.g. loop/size_spec.rb
+
+ruby_version_is "1.9.3" do
+  describe "Enumerator#size" do
+    before :each do
+      @e = Enumerator.new{|y| y << :foo << :bar}
+    end
+
+    describe "when called without a block" do
+      it "returns nil when size was not specified" do
+        @e.size.should == nil
+      end
+
+      it "returns the specified size" do
+        @e.size = 42
+        @e.size.should == 42
+      end
+
+      it "returns the result of the given size block or method" do
+        values = [42, 1, 2, 3]
+        @e.size = Proc.new{ values.pop }
+        @e.size.should == 3
+        @e.size.should == 2
+        def values.shift(x)
+          super()
+        end
+        @e.size = values.method(:shift)
+        @e.size.should == 42
+        @e.size.should == 1
+      end
+
+      it "yields the receiver and the arguments to the given size block or method" do
+        values = [42, 1, 2, 3]
+        def values.foo(*args)
+          each{|x| yield x}
+        end
+        s = "hello"
+        @e = values.to_enum(:foo, s)
+        receiver = nil
+        arg = nil
+        @e.size = lambda{|r, a| receiver = r; arg = a; r.size }
+        @e.size.should == 4
+        receiver.should equal(values)
+        arg.should equal(s)
+      end
+
+      it "is lazy and doesn't iterate" do
+        lambda{
+          Enumerator.new{ raise "be lazy!" }.size
+        }.should_not raise_error
+      end
+    end
+
+    describe "when called with a block" do
+      it "returns the actual size when size was not specified" do
+        @e.size{}.should == 2
+      end
+
+      it "ignores the specified size" do
+        @e.size = 42
+        @e.size{}.should == 2
+      end
+
+      it "ignores the given size block or method" do
+        @e.size = Proc.new{ raise "ignore me" }
+        lambda{
+          @e.size{}
+        }.should_not raise_error
+      end
+    end
+  end
+
+  describe "Array#permutation.size" do
+    it "returns the number of permutations" do
+      [].permutation.size.should == 1
+      [1].permutation.size.should == 1
+      [1, 2].permutation(3).size.should == 0
+      (1..5).to_a.permutation(2).size.should == 20
+      (1..100).to_a.permutation.size.should == 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000
+    end
+  end
+
+  describe "Array#combination.size" do
+    it "returns the number of combinations" do
+      [].combination(0).size.should == 1
+      [1].combination(0).size.should == 1
+      [1].combination(1).size.should == 1
+      [1, 2].combination(3).size.should == 0
+      (1..5).to_a.combination(2).size.should == 10
+      (1..5).to_a.combination(3).size.should == 10
+      (1..100).to_a.combination(40).size.should == 13746234145802811501267369720
+    end
+  end
+
+  describe "Array#repeated_permutation.size" do
+    it "returns the number of repeated permutations" do
+      [ ].repeated_permutation(0).size.should == 1
+      [ ].repeated_permutation(2).size.should == 0
+      [1].repeated_permutation(0).size.should == 1
+      [1].repeated_permutation(5).size.should == 1
+      [1].repeated_permutation(-1).size.should == 0
+      (1..100).to_a.repeated_permutation(40).size.should == 100**40
+    end
+  end
+
+  describe "Array#repeated_combination.size" do
+    it "returns the number of repeated combinations" do
+      [ ].repeated_combination(0).size.should == 1
+      [ ].repeated_combination(2).size.should == 0
+      [1].repeated_combination(0).size.should == 1
+      [1].repeated_combination(5).size.should == 1
+      [1].repeated_combination(-1).size.should == 0
+      (1..5).to_a.repeated_combination(3).size.should == 35
+      (1..100).to_a.repeated_combination(40).size.should == 126279609474586092455213621207360700
+    end
+  end
+
+  describe "Array#cycle.size" do
+    it "returns the size" do
+      [ ].cycle.size.should == 0
+      [1].cycle.size.should == Float::INFINITY
+      [1,2].cycle(3).size.should == 6
+    end
+  end
+
+  describe "Kernel#loop.size" do
+    it "returns Infinity" do
+      loop.size.should == Float::INFINITY
+    end
+  end
+
+  describe "Enumerator#size when created from an enumerable" do
+    before :each do
+      @methods = [:each_with_index, :each_entry, :reverse_each,
+                  :find_all, :reject, :map, :flat_map, :partition, :group_by, :sort_by,
+                  :min_by, :max_by, :minmax_by ]
+    end
+
+    it "returns nil if the Enumerable has no size method" do
+      e = EnumeratorSpecs::Numerous.new
+      @methods.each do |method|
+        e.send(method).size.should == nil
+      end
+      e.each_with_object(:foo).size.should == nil
+    end
+
+    it "uses the size method if there is one" do
+      e = EnumeratorSpecs::SizedNumerous.new
+      @methods.each do |method|
+        e.send(method).size.should == 6
+      end
+      e.each_with_object(:foo).size.should == 6
+    end
+  end
+
+  describe "Enumerable#each_slize.size" do
+    it "returns the right size" do
+      e = EnumeratorSpecs::SizedNumerous.new(*1..42)
+      e.each_slice(3).size.should == 14
+      e.each_slice(4).size.should == 11
+    end
+  end
+
+  describe "Enumerable#each_cons.size" do
+    it "returns the right size" do
+      e = EnumeratorSpecs::SizedNumerous.new(*1..42)
+      e.each_cons(3).size.should == 40
+      e.each_cons(50).size.should == 0
+    end
+  end
+
+  describe "Enumerable#cycle.size" do
+    it "returns the right size" do
+      e = EnumeratorSpecs::SizedNumerous.new
+      e.cycle(3).size.should == 18
+      e.cycle(0).size.should == 0
+      e.cycle(-1).size.should == 0
+      e.cycle.size.should == Float::INFINITY
+    end
+  end
+
+  describe "Enumerator#size when created from a Hash" do
+    it "returns the hash's size" do
+      h = {"hello" => "world", :foo => :bar, 1 => 2}
+      [ :each, :each_value, :each_key, :each_pair,
+        :keep_if, :delete_if, :reject!, :select, :select!
+      ].each do |method|
+        h.send(method).size.should == 3
+      end
+    end
+  end
+
+  describe "Enumerator#size when created from ENV" do
+    it "returns the number of environment variables" do
+      s = ENV.to_a.size
+      [ :each, :each_value, :each_key, :each_pair,
+        :keep_if, :delete_if, :reject!, :select, :select!
+      ].each do |method|
+        ENV.send(method).size.should == s
+      end
+    end
+  end
+
+  describe "Enumerator#size when created from a Struct" do
+    it "returns the number of fields" do
+      klass = Struct.new(:foo, :bar, :baz)
+      s = klass.new
+      [ :each, :each_pair, :select
+      ].each do |method|
+        s.send(method).size.should == 3
+      end
+    end
+  end
+
+  describe "Numeric#step.size" do
+    it "returns the right size for fixnums" do
+      42.step(99, 3).size.should == 20
+      42.step(100, 3).size.should == 20
+      42.step(20, 3).size.should == 0
+      42.step(20, -3).size.should == 8
+      10.step(20).size.should == 11
+    end
+
+    it "returns the right size for floats" do
+      0.5.step(4.2, 0.3).size.should == 13
+      0.5.step(4.2, -0.3).size.should == 0
+      -0.5.step(-4.2, -0.3).size.should == 13
+    end
+
+    it "returns the right size for bignums" do
+      (2 ** 100).step(2 ** 100 + 42, 2).size.should == 22
+      (2 ** 100).step(2 ** 100 - 41, 2).size.should == 0
+      (2 ** 100).step(2 ** 100 - 41, -2).size.should == 21
+    end
+  end
+
+  describe "Numeric#upto.size" do
+    it "returns the right size for fixnums" do
+      42.upto(99).size.should == 58
+      42.upto(20).size.should == 0
+    end
+
+    it "returns the right size for bignum arguments" do
+      (2 ** 100).upto(2 ** 100 + 42).size.should == 43
+      (2 ** 100).upto(2 ** 100 - 42).size.should == 0
+    end
+  end
+
+  describe "Numeric#downto.size" do
+    it "returns the right size for fixnums" do
+      42.downto(99).size.should == 0
+      42.downto(20).size.should == 23
+    end
+
+    it "returns the right size for bignum arguments" do
+      (2 ** 100).downto(2 ** 100 + 42).size.should == 0
+      (2 ** 100).downto(2 ** 100 - 42).size.should == 43
+    end
+  end
+
+  describe "Numeric#times.size" do
+    it "returns the right size" do
+      5.times.size.should == 5
+      (2 ** 99).times.size.should == 2 ** 99
+    end
+
+    it "returns 0 for negative integers" do
+      (-5).times.size.should == 0
+      (-2 ** 99).times.size.should == 0
+    end
+  end
+
+  describe "String#each_byte.size" do
+    it "returns the size" do
+      "Môntréål".each_byte.size.should == 11
+    end
+  end
+
+  describe "String#each_char.size" do
+    it "returns the number of characters" do
+      "Môntréål".each_char.size.should == 8
+    end
+  end
+
+  describe "String#each_codepoint.size" do
+    it "returns the number of characters" do
+      "Môntréål".each_codepoint.size.should == 8
+    end
+  end
+end
diff --git a/core/kernel/to_enum_spec.rb b/core/kernel/to_enum_spec.rb
@@ -3,5 +3,15 @@
 ruby_version_is "1.9" do
   describe "Kernel#to_enum" do
     it "needs to be reviewed for spec completeness"
+
+    ruby_version_is "1.9.3" do
+      it "accepts a size block" do
+        x = "foo"
+        args = nil
+        enum = x.to_enum(:foo, :bar){|*a| args = a; 42}
+        enum.size.should == 42
+        args.should == [x, :bar]
+      end
+    end
   end
 end