1 files changed, 78 insertions, 0 deletions
diff --git a/spec/ruby/core/enumerator/produce_spec.rb b/spec/ruby/core/enumerator/produce_spec.rb
new file mode 100644
index 0000000000..eb1b09294e
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+++ b/spec/ruby/core/enumerator/produce_spec.rb
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+require_relative '../../spec_helper'
+
+describe "Enumerator.produce" do
+  it "creates an infinite enumerator" do
+    enum = Enumerator.produce(0) { |prev| prev + 1 }
+
+    enum.size.should == Float::INFINITY
+    enum.take(5).should == [0, 1, 2, 3, 4]
+  end
+
+  it "terminates iteration when block raises StopIteration exception" do
+    enum = Enumerator.produce(0) do | prev|
+      raise StopIteration if prev >= 2
+      prev + 1
+    end
+
+    enum.to_a.should == [0, 1, 2]
+  end
+
+  context "when initial value skipped" do
+    it "uses nil instead" do
+      ScratchPad.record []
+      enum = Enumerator.produce { |prev| ScratchPad << prev; (prev || 0) + 1 }
+
+      enum.take(3).should == [1, 2, 3]
+      ScratchPad.recorded.should == [nil, 1, 2]
+    end
+
+    it "starts enumerable from result of first block call" do
+      array = "a\nb\nc\nd".lines
+      lines = Enumerator.produce { array.shift }.take_while { |s| s }
+
+      lines.should == ["a\n", "b\n", "c\n", "d"]
+    end
+  end
+
+  it "raises ArgumentError when no block is given" do
+    -> { Enumerator.produce }.should.raise(ArgumentError, "no block given")
+  end
+
+  ruby_version_is ""..."4.0" do
+    it "accepts keyword arguments as the initial value" do
+      enum = Enumerator.produce(a: 1, b: 1) {}
+      enum.take(1).should == [{a: 1, b: 1}]
+    end
+  end
+
+  ruby_version_is "4.0" do
+    it "raises ArgumentError for unknown keyword arguments" do
+      -> { Enumerator.produce(a: 1, b: 1) {} }.should.raise(ArgumentError, /unknown keywords/)
+    end
+  end
+
+  ruby_version_is "4.0" do
+    context "with size keyword argument" do
+      it "sets the size of the enumerator" do
+        enum = Enumerator.produce(0, size: 10) { |n| n + 1 }
+
+        enum.size.should == 10
+        enum.take(5).should == [0, 1, 2, 3, 4]
+      end
+
+      it "accepts a callable" do
+        enum = Enumerator.produce(0, size: -> { 5 * 5 }) { |n| n + 1 }
+
+        enum.size.should == 25
+        enum.take(5).should == [0, 1, 2, 3, 4]
+      end
+
+      it "accepts nil" do
+        enum = Enumerator.produce(0, size: nil) { |n| n + 1 }
+
+        enum.size.should == nil
+        enum.take(5).should == [0, 1, 2, 3, 4]
+      end
+    end
+  end
+end