1 files changed, 82 insertions, 0 deletions
diff --git a/spec/ruby/core/enumerator/lazy/grep_spec.rb b/spec/ruby/core/enumerator/lazy/grep_spec.rb
new file mode 100644
index 0000000000..372be80d61
--- /dev/null
+++ b/spec/ruby/core/enumerator/lazy/grep_spec.rb
@@ -0,0 +1,82 @@
+# -*- encoding: us-ascii -*-
+
+require File.expand_path('../../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "Enumerator::Lazy#grep" do
+  before :each do
+    @yieldsmixed = EnumeratorLazySpecs::YieldsMixed.new.to_enum.lazy
+    @eventsmixed = EnumeratorLazySpecs::EventsMixed.new.to_enum.lazy
+    ScratchPad.record []
+  end
+
+  after :each do
+    ScratchPad.clear
+  end
+
+  it "requires an argument" do
+    Enumerator::Lazy.instance_method(:grep).arity.should == 1
+  end
+
+  it "returns a new instance of Enumerator::Lazy" do
+    ret = @yieldsmixed.grep(Object) {}
+    ret.should be_an_instance_of(Enumerator::Lazy)
+    ret.should_not equal(@yieldsmixed)
+
+    ret = @yieldsmixed.grep(Object)
+    ret.should be_an_instance_of(Enumerator::Lazy)
+    ret.should_not equal(@yieldsmixed)
+  end
+
+  it "sets #size to nil" do
+    Enumerator::Lazy.new(Object.new, 100) {}.grep(Object) {}.size.should == nil
+    Enumerator::Lazy.new(Object.new, 100) {}.grep(Object).size.should == nil
+  end
+
+  describe "when the returned lazy enumerator is evaluated by Enumerable#first" do
+    it "stops after specified times when not given a block" do
+      (0..Float::INFINITY).lazy.grep(Integer).first(3).should == [0, 1, 2]
+
+      @eventsmixed.grep(BasicObject).first(1)
+      ScratchPad.recorded.should == [:before_yield]
+    end
+
+    it "stops after specified times when given a block" do
+      (0..Float::INFINITY).lazy.grep(Integer, &:succ).first(3).should == [1, 2, 3]
+
+      @eventsmixed.grep(BasicObject) {}.first(1)
+      ScratchPad.recorded.should == [:before_yield]
+    end
+  end
+
+  it "calls the block with a gathered array when yield with multiple arguments" do
+    yields = []
+    @yieldsmixed.grep(BasicObject) { |v| yields << v }.force
+    yields.should == EnumeratorLazySpecs::YieldsMixed.gathered_yields
+
+    @yieldsmixed.grep(BasicObject).force.should == yields
+  end
+
+  describe "on a nested Lazy" do
+    it "sets #size to nil" do
+      Enumerator::Lazy.new(Object.new, 100) {}.grep(Object) {}.size.should == nil
+      Enumerator::Lazy.new(Object.new, 100) {}.grep(Object).size.should == nil
+    end
+
+    describe "when the returned lazy enumerator is evaluated by Enumerable#first" do
+      it "stops after specified times when not given a block" do
+        (0..Float::INFINITY).lazy.grep(Integer).grep(Object).first(3).should == [0, 1, 2]
+
+        @eventsmixed.grep(BasicObject).grep(Object).first(1)
+        ScratchPad.recorded.should == [:before_yield]
+      end
+
+      it "stops after specified times when given a block" do
+        (0..Float::INFINITY).lazy.grep(Integer) { |n| n > 3 ? n : false }.grep(Integer) { |n| n.even? ? n : false }.first(3).should == [4, false, 6]
+
+        @eventsmixed.grep(BasicObject) {}.grep(Object) {}.first(1)
+        ScratchPad.recorded.should == [:before_yield]
+      end
+    end
+  end
+end