1 files changed, 87 insertions, 0 deletions
diff --git a/spec/ruby/core/range/overlap_spec.rb b/spec/ruby/core/range/overlap_spec.rb
new file mode 100644
index 0000000000..201cd2b1ff
--- /dev/null
+++ b/spec/ruby/core/range/overlap_spec.rb
@@ -0,0 +1,87 @@
+require_relative '../../spec_helper'
+
+describe "Range#overlap?" do
+  it "returns true if other Range overlaps self" do
+    (0..2).overlap?(1..3).should == true
+    (1..3).overlap?(0..2).should == true
+    (0..2).overlap?(0..2).should == true
+    (0..3).overlap?(1..2).should == true
+    (1..2).overlap?(0..3).should == true
+
+    ('a'..'c').overlap?('b'..'d').should == true
+  end
+
+  it "returns false if other Range does not overlap self" do
+    (0..2).overlap?(3..4).should == false
+    (0..2).overlap?(-4..-1).should == false
+
+    ('a'..'c').overlap?('d'..'f').should == false
+  end
+
+  it "raises TypeError when called with non-Range argument" do
+    -> {
+      (0..2).overlap?(1)
+    }.should.raise(TypeError, "wrong argument type Integer (expected Range)")
+  end
+
+  it "returns true when beginningless and endless Ranges overlap" do
+    (0..2).overlap?(..3).should == true
+    (0..2).overlap?(..1).should == true
+    (0..2).overlap?(..0).should == true
+
+    (..3).overlap?(0..2).should == true
+    (..1).overlap?(0..2).should == true
+    (..0).overlap?(0..2).should == true
+
+    (0..2).overlap?(-1..).should == true
+    (0..2).overlap?(1..).should == true
+    (0..2).overlap?(2..).should == true
+
+    (-1..).overlap?(0..2).should == true
+    (1..).overlap?(0..2).should == true
+    (2..).overlap?(0..2).should == true
+
+    (0..).overlap?(2..).should == true
+    (..0).overlap?(..2).should == true
+  end
+
+  it "returns false when beginningless and endless Ranges do not overlap" do
+    (0..2).overlap?(..-1).should == false
+    (0..2).overlap?(3..).should == false
+
+    (..-1).overlap?(0..2).should == false
+    (3..).overlap?(0..2).should == false
+  end
+
+  it "returns false when Ranges are not compatible" do
+    (0..2).overlap?('a'..'d').should == false
+  end
+
+  it "return false when self is empty" do
+    (2..0).overlap?(1..3).should == false
+    (2...2).overlap?(1..3).should == false
+    (1...1).overlap?(1...1).should == false
+    (2..0).overlap?(2..0).should == false
+
+    ('c'..'a').overlap?('b'..'d').should == false
+    ('a'...'a').overlap?('b'..'d').should == false
+    ('b'...'b').overlap?('b'...'b').should == false
+    ('c'...'a').overlap?('c'...'a').should == false
+  end
+
+  it "return false when other Range is empty" do
+    (1..3).overlap?(2..0).should == false
+    (1..3).overlap?(2...2).should == false
+
+    ('b'..'d').overlap?('c'..'a').should == false
+    ('b'..'d').overlap?('c'...'c').should == false
+  end
+
+  it "takes into account exclusive end" do
+    (0...2).overlap?(2..4).should == false
+    (2..4).overlap?(0...2).should == false
+
+    ('a'...'c').overlap?('c'..'e').should == false
+    ('c'..'e').overlap?('a'...'c').should == false
+  end
+end