1 files changed, 70 insertions, 0 deletions
diff --git a/spec/ruby/core/module/deprecate_constant_spec.rb b/spec/ruby/core/module/deprecate_constant_spec.rb
new file mode 100644
index 0000000000..597379eb87
--- /dev/null
+++ b/spec/ruby/core/module/deprecate_constant_spec.rb
@@ -0,0 +1,70 @@
+require_relative '../../spec_helper'
+
+describe "Module#deprecate_constant" do
+  before :each do
+    @module = Module.new
+    @value = :value
+    @module::PUBLIC1 = @value
+    @module::PUBLIC2 = @value
+    @module::PRIVATE = @value
+    @module.private_constant :PRIVATE
+    @module.deprecate_constant :PRIVATE
+  end
+
+  describe "when accessing the deprecated module" do
+    it "passes the accessing" do
+      @module.deprecate_constant :PUBLIC1
+
+      value = nil
+      -> {
+        value = @module::PUBLIC1
+      }.should complain(/warning: constant .+::PUBLIC1 is deprecated/)
+      value.should.equal?(@value)
+
+      -> { @module::PRIVATE }.should.raise(NameError)
+    end
+
+    it "warns with a message" do
+      @module.deprecate_constant :PUBLIC1
+
+      -> { @module::PUBLIC1 }.should complain(/warning: constant .+::PUBLIC1 is deprecated/)
+      -> { @module.const_get :PRIVATE }.should complain(/warning: constant .+::PRIVATE is deprecated/)
+    end
+
+    it "does not warn if Warning[:deprecated] is false" do
+      @module.deprecate_constant :PUBLIC1
+
+      deprecated = Warning[:deprecated]
+      begin
+        Warning[:deprecated] = false
+        -> { @module::PUBLIC1 }.should_not complain
+      ensure
+        Warning[:deprecated] = deprecated
+      end
+    end
+  end
+
+  ruby_bug '#20900', ''...'3.4' do
+    describe "when removing the deprecated module" do
+      it "warns with a message" do
+        @module.deprecate_constant :PUBLIC1
+        -> { @module.module_eval {remove_const :PUBLIC1} }.should complain(/warning: constant .+::PUBLIC1 is deprecated/)
+      end
+    end
+  end
+
+  it "accepts multiple symbols and strings as constant names" do
+    @module.deprecate_constant "PUBLIC1", :PUBLIC2
+
+    -> { @module::PUBLIC1 }.should complain(/warning: constant .+::PUBLIC1 is deprecated/)
+    -> { @module::PUBLIC2 }.should complain(/warning: constant .+::PUBLIC2 is deprecated/)
+  end
+
+  it "returns self" do
+    @module.deprecate_constant(:PUBLIC1).should.equal?(@module)
+  end
+
+  it "raises a NameError when given an undefined name" do
+    -> { @module.deprecate_constant :UNDEFINED }.should.raise(NameError)
+  end
+end