2 files changed, 51 insertions, 6 deletions
diff --git a/spec/ruby/core/env/shared/to_hash.rb b/spec/ruby/core/env/shared/to_hash.rb
index 254054c14d..bfa5699e8d 100644
--- a/spec/ruby/core/env/shared/to_hash.rb
+++ b/spec/ruby/core/env/shared/to_hash.rb
@@ -1,10 +1,17 @@
 describe :env_to_hash, shared: true do
+  before :each do
+    @saved_foo = ENV["foo"]
+  end
+
+  after :each do
+    ENV["foo"]= @saved_foo
+  end
+
   it "returns the ENV as a hash" do
     ENV["foo"] = "bar"
     h = ENV.send(@method)
     h.should be_an_instance_of(Hash)
     h["foo"].should == "bar"
-    ENV.delete "foo"
   end
 
   it "uses the locale encoding for keys" do
@@ -18,5 +25,9 @@ describe :env_to_hash, shared: true do
   it "duplicates the ENV when converting to a Hash" do
     h = ENV.send(@method)
     h.should_not equal ENV
+    h.size.should == ENV.size
+    h.each_pair do |k, v|
+      ENV[k].should == v
+    end
   end
 end
diff --git a/spec/ruby/core/env/shared/update.rb b/spec/ruby/core/env/shared/update.rb
index 430cda5185..129a56544c 100644
--- a/spec/ruby/core/env/shared/update.rb
+++ b/spec/ruby/core/env/shared/update.rb
@@ -9,8 +9,8 @@ describe :env_update, shared: true do
     ENV["bar"] = @saved_bar
   end
 
-  it "adds the parameter hash to ENV" do
-    ENV.send @method, {"foo" => "0", "bar" => "1"}
+  it "adds the parameter hash to ENV, returning ENV" do
+    ENV.send(@method, "foo" => "0", "bar" => "1").should equal(ENV)
     ENV["foo"].should == "0"
     ENV["bar"].should == "1"
   end
@@ -19,17 +19,43 @@ describe :env_update, shared: true do
     ENV.send(@method, {"foo" => "0", "bar" => "1"}).should equal(ENV)
   end
 
-  it "yields key, the old value and the new value when replacing entries" do
+  it "yields key, the old value and the new value when replacing an entry" do
     ENV.send @method, {"foo" => "0", "bar" => "3"}
     a = []
     ENV.send @method, {"foo" => "1", "bar" => "4"} do |key, old, new|
       a << [key, old, new]
+      new
+    end
+    a[0].should == ["foo", "0", "1"]
+    a[1].should == ["bar", "3", "4"]
+  end
+
+  it "yields key, the old value and the new value when replacing an entry" do
+    ENV.send @method, {"foo" => "0", "bar" => "3"}
+    ENV.send @method, {"foo" => "1", "bar" => "4"} do |key, old, new|
       (new.to_i + 1).to_s
     end
     ENV["foo"].should == "2"
     ENV["bar"].should == "5"
-    a[0].should == ["foo", "0", "1"]
-    a[1].should == ["bar", "3", "4"]
+  end
+
+  ruby_version_is "2.7" do
+    # BUG: https://bugs.ruby-lang.org/issues/16192
+    it "does not evaluate the block when the name is new" do
+      ENV.delete("bar")
+      ENV.send @method, {"foo" => "0"}
+      ENV.send(@method, "bar" => "1") { |key, old, new| fail "Should not get here" }
+      ENV["bar"].should == "1"
+    end
+
+    # BUG: https://bugs.ruby-lang.org/issues/16192
+    it "does not use the block's return value as the value when the name is new" do
+      ENV.delete("bar")
+      ENV.send @method, {"foo" => "0"}
+      ENV.send(@method, "bar" => "1") { |key, old, new| "Should not use this value" }
+      ENV["foo"].should == "0"
+      ENV["bar"].should == "1"
+    end
   end
 
   it "returns ENV when block given" do
@@ -44,6 +70,14 @@ describe :env_update, shared: true do
     -> { ENV.send @method, "foo" => Object.new }.should raise_error(TypeError, "no implicit conversion of Object into String")
   end
 
+  it "raises Errno::EINVAL when a name contains the '=' character" do
+    -> { ENV.send(@method, "foo=" => "bar") }.should raise_error(Errno::EINVAL)
+  end
+
+  it "raises Errno::EINVAL when a name is an empty string" do
+    -> { ENV.send(@method, "" => "bar") }.should raise_error(Errno::EINVAL)
+  end
+
   it "updates good data preceding an error" do
     ENV["foo"] = "0"
     begin