6 files changed, 71 insertions, 49 deletions
diff --git a/spec/ruby/core/enumerator/lazy/compact_spec.rb b/spec/ruby/core/enumerator/lazy/compact_spec.rb
new file mode 100644
index 0000000000..e678bc71eb
--- /dev/null
+++ b/spec/ruby/core/enumerator/lazy/compact_spec.rb
@@ -0,0 +1,16 @@
+require_relative '../../../spec_helper'
+require_relative 'fixtures/classes'
+
+ruby_version_is '3.1' do
+  describe "Enumerator::Lazy#compact" do
+    it 'returns array without nil elements' do
+      arr = [1, nil, 3, false, 5].to_enum.lazy.compact
+      arr.should be_an_instance_of(Enumerator::Lazy)
+      arr.force.should == [1, 3, false, 5]
+    end
+
+    it "sets #size to nil" do
+      Enumerator::Lazy.new(Object.new, 100) {}.compact.size.should == nil
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/lazy/eager_spec.rb b/spec/ruby/core/enumerator/lazy/eager_spec.rb
index 30ba2dfe0e..592da4fd8c 100644
--- a/spec/ruby/core/enumerator/lazy/eager_spec.rb
+++ b/spec/ruby/core/enumerator/lazy/eager_spec.rb
@@ -1,29 +1,27 @@
 require_relative '../../../spec_helper'
 
-ruby_version_is "2.7" do
-  describe "Enumerator::Lazy#eager" do
-    it "returns a non-lazy Enumerator converted from the lazy enumerator" do
-      enum = [1, 2, 3].lazy
+describe "Enumerator::Lazy#eager" do
+  it "returns a non-lazy Enumerator converted from the lazy enumerator" do
+    enum = [1, 2, 3].lazy
 
-      enum.class.should == Enumerator::Lazy
-      enum.eager.class.should == Enumerator
-    end
+    enum.class.should == Enumerator::Lazy
+    enum.eager.class.should == Enumerator
+  end
 
-    it "does not enumerate an enumerator" do
-      ScratchPad.record []
+  it "does not enumerate an enumerator" do
+    ScratchPad.record []
 
-      sequence = [1, 2, 3]
-      enum_lazy = Enumerator::Lazy.new(sequence) do |yielder, value|
-        yielder << value
-        ScratchPad << value
-      end
+    sequence = [1, 2, 3]
+    enum_lazy = Enumerator::Lazy.new(sequence) do |yielder, value|
+      yielder << value
+      ScratchPad << value
+    end
 
-      ScratchPad.recorded.should == []
-      enum = enum_lazy.eager
-      ScratchPad.recorded.should == []
+    ScratchPad.recorded.should == []
+    enum = enum_lazy.eager
+    ScratchPad.recorded.should == []
 
-      enum.map { |i| i }.should == [1, 2, 3]
-      ScratchPad.recorded.should == [1, 2, 3]
-    end
+    enum.map { |i| i }.should == [1, 2, 3]
+    ScratchPad.recorded.should == [1, 2, 3]
   end
 end
diff --git a/spec/ruby/core/enumerator/lazy/filter_map_spec.rb b/spec/ruby/core/enumerator/lazy/filter_map_spec.rb
index 3480af0865..99dd59cebe 100644
--- a/spec/ruby/core/enumerator/lazy/filter_map_spec.rb
+++ b/spec/ruby/core/enumerator/lazy/filter_map_spec.rb
@@ -3,14 +3,12 @@
 require_relative '../../../spec_helper'
 require_relative 'fixtures/classes'
 
-ruby_version_is "2.7" do
-  describe "Enumerator::Lazy#filter_map" do
-    it "maps only truthy results" do
-      (1..Float::INFINITY).lazy.filter_map { |i| i if i.odd? }.first(4).should == [1, 3, 5, 7]
-    end
+describe "Enumerator::Lazy#filter_map" do
+  it "maps only truthy results" do
+    (1..Float::INFINITY).lazy.filter_map { |i| i if i.odd? }.first(4).should == [1, 3, 5, 7]
+  end
 
-    it "does not map false results" do
-      (1..Float::INFINITY).lazy.filter_map { |i| i.odd? ? i : false }.first(4).should == [1, 3, 5, 7]
-    end
+  it "does not map false results" do
+    (1..Float::INFINITY).lazy.filter_map { |i| i.odd? ? i : false }.first(4).should == [1, 3, 5, 7]
   end
 end
diff --git a/spec/ruby/core/enumerator/lazy/initialize_spec.rb b/spec/ruby/core/enumerator/lazy/initialize_spec.rb
index f23018d010..e1e0b1d608 100644
--- a/spec/ruby/core/enumerator/lazy/initialize_spec.rb
+++ b/spec/ruby/core/enumerator/lazy/initialize_spec.rb
@@ -56,8 +56,8 @@ describe "Enumerator::Lazy#initialize" do
   end
 
   describe "on frozen instance" do
-    it "raises a RuntimeError" do
-      -> {  @uninitialized.freeze.send(:initialize, @receiver) {} }.should raise_error(RuntimeError)
+    it "raises a FrozenError" do
+      -> {  @uninitialized.freeze.send(:initialize, @receiver) {} }.should raise_error(FrozenError)
     end
   end
 end
diff --git a/spec/ruby/core/enumerator/lazy/lazy_spec.rb b/spec/ruby/core/enumerator/lazy/lazy_spec.rb
index cde9b31066..0fb104e25a 100644
--- a/spec/ruby/core/enumerator/lazy/lazy_spec.rb
+++ b/spec/ruby/core/enumerator/lazy/lazy_spec.rb
@@ -16,6 +16,10 @@ describe "Enumerator::Lazy" do
     ]
     lazy_methods += [:chunk_while, :uniq]
 
+    ruby_version_is '3.1' do
+      lazy_methods += [:compact]
+    end
+
     Enumerator::Lazy.instance_methods(false).should include(*lazy_methods)
   end
 end
diff --git a/spec/ruby/core/enumerator/lazy/with_index_spec.rb b/spec/ruby/core/enumerator/lazy/with_index_spec.rb
index 3a59ba4116..a6b5c38777 100644
--- a/spec/ruby/core/enumerator/lazy/with_index_spec.rb
+++ b/spec/ruby/core/enumerator/lazy/with_index_spec.rb
@@ -3,28 +3,34 @@
 require_relative '../../../spec_helper'
 require_relative 'fixtures/classes'
 
-ruby_version_is "2.7" do
-  describe "Enumerator::Lazy#with_index" do
-    it "enumerates with an index" do
-      (0..Float::INFINITY).lazy.with_index.map { |i, idx| [i, idx] }.first(3).should == [[0, 0], [1, 1], [2, 2]]
-    end
+describe "Enumerator::Lazy#with_index" do
+  it "enumerates with an index" do
+    (0..Float::INFINITY).lazy.with_index.map { |i, idx| [i, idx] }.first(3).should == [[0, 0], [1, 1], [2, 2]]
+  end
+
+  it "enumerates with an index starting at a given offset" do
+    (0..Float::INFINITY).lazy.with_index(3).map { |i, idx| [i, idx] }.first(3).should == [[0, 3], [1, 4], [2, 5]]
+  end
 
-    it "enumerates with an index starting at a given offset" do
-      (0..Float::INFINITY).lazy.with_index(3).map { |i, idx| [i, idx] }.first(3).should == [[0, 3], [1, 4], [2, 5]]
-    end
+  it "enumerates with an index starting at 0 when offset is nil" do
+    (0..Float::INFINITY).lazy.with_index(nil).map { |i, idx| [i, idx] }.first(3).should == [[0, 0], [1, 1], [2, 2]]
+  end
 
-    it "enumerates with an index starting at 0 when offset is nil" do
-      (0..Float::INFINITY).lazy.with_index(nil).map { |i, idx| [i, idx] }.first(3).should == [[0, 0], [1, 1], [2, 2]]
-    end
+  it "raises TypeError when offset does not convert to Integer" do
+    -> { (0..Float::INFINITY).lazy.with_index(false).map { |i, idx| i }.first(3) }.should raise_error(TypeError)
+  end
 
-    it "raises TypeError when offset does not convert to Integer" do
-      -> { (0..Float::INFINITY).lazy.with_index(false).map { |i, idx| i }.first(3) }.should raise_error(TypeError)
-    end
+  it "enumerates with a given block" do
+    result = []
+    (0..Float::INFINITY).lazy.with_index { |i, idx| result << [i * 2, idx] }.first(3)
+    result.should == [[0,0],[2,1],[4,2]]
+  end
 
-    it "enumerates with a given block" do
-      result = []
-      (0..Float::INFINITY).lazy.with_index { |i, idx| result << [i * 2, idx] }.first(3)
-      result.should == [[0,0],[2,1],[4,2]]
-    end
+  it "resets after a new call to each" do
+    enum = (0..2).lazy.with_index.map { |i, idx| [i, idx] }
+    result = []
+    enum.each { |i, idx| result << [i, idx] }
+    enum.each { |i, idx| result << [i, idx] }
+    result.should == [[0,0], [1,1], [2,2], [0,0], [1,1], [2,2]]
   end
 end