1 files changed, 47 insertions, 1 deletions
diff --git a/spec/ruby/core/array/element_set_spec.rb b/spec/ruby/core/array/element_set_spec.rb
index 2e01e838e9..1c143f3e37 100644
--- a/spec/ruby/core/array/element_set_spec.rb
+++ b/spec/ruby/core/array/element_set_spec.rb
@@ -439,7 +439,6 @@ end
 
 ruby_version_is "2.6" do
   describe "Array#[]= with [m..]" do
-
     it "just sets the section defined by range to nil even if the rhs is nil" do
       a = [1, 2, 3, 4, 5]
       a[eval("(2..)")] = nil
@@ -476,6 +475,53 @@ ruby_version_is "2.6" do
   end
 end
 
+ruby_version_is "2.7" do
+  describe "Array#[]= with [..n] and [...n]" do
+    it "just sets the section defined by range to nil even if the rhs is nil" do
+      a = [1, 2, 3, 4, 5]
+      a[eval("(..2)")] = nil
+      a.should == [nil, 4, 5]
+      a[eval("(...2)")] = nil
+      a.should == [nil, 5]
+    end
+
+    it "just sets the section defined by range to nil if n < 0 and the rhs is nil" do
+      a = [1, 2, 3, 4, 5]
+      a[eval("(..-3)")] = nil
+      a.should == [nil, 4, 5]
+      a[eval("(...-1)")] = [nil, 5]
+    end
+
+    it "replaces the section defined by range" do
+      a = [6, 5, 4, 3, 2, 1]
+      a[eval("(...3)")] = 9
+      a.should == [9, 3, 2, 1]
+      a[eval("(..2)")] = [7, 7, 7, 7, 7]
+      a.should == [7, 7, 7, 7, 7, 1]
+    end
+
+    it "replaces the section if n < 0" do
+      a = [1, 2, 3, 4, 5]
+      a[eval("(..-2)")] = [7, 8, 9]
+      a.should == [7, 8, 9, 5]
+    end
+
+    it "replaces everything if n > the array size" do
+      a = [1, 2, 3]
+      a[eval("(...7)")] = [4]
+      a.should == [4]
+    end
+
+    it "inserts at the beginning if n < negative the array size" do
+      a = [1, 2, 3]
+      a[eval("(..-7)")] = [4]
+      a.should == [4, 1, 2, 3]
+      a[eval("(...-10)")] = [6]
+      a.should == [6, 4, 1, 2, 3]
+    end
+  end
+end
+
 describe "Array#[] after a shift" do
   it "works for insertion" do
     a = [1,2]