1 files changed, 101 insertions, 0 deletions
diff --git a/spec/ruby/language/safe_navigator_spec.rb b/spec/ruby/language/safe_navigator_spec.rb
new file mode 100644
index 0000000000..a8b29dc5a3
--- /dev/null
+++ b/spec/ruby/language/safe_navigator_spec.rb
@@ -0,0 +1,101 @@
+require File.expand_path("../../spec_helper", __FILE__)
+
+ruby_version_is "2.3" do
+  describe "Safe navigator" do
+    it "requires a method name to be provided" do
+      lambda { eval("obj&. {}") }.should raise_error(SyntaxError)
+    end
+
+    context "when context is nil" do
+      it "always returns nil" do
+        eval("nil&.unknown").should == nil
+        eval("[][10]&.unknown").should == nil
+      end
+
+      it "can be chained" do
+        eval("nil&.one&.two&.three").should == nil
+      end
+
+      it "doesn't evaluate arguments" do
+        obj = Object.new
+        obj.should_not_receive(:m)
+        eval("nil&.unknown(obj.m) { obj.m }")
+      end
+    end
+
+    context "when context is false" do
+      it "calls the method" do
+        eval("false&.to_s").should == "false"
+
+        lambda { eval("false&.unknown") }.should raise_error(NoMethodError)
+      end
+    end
+
+    context "when context is truthy" do
+      it "calls the method" do
+        eval("1&.to_s").should == "1"
+
+        lambda { eval("1&.unknown") }.should raise_error(NoMethodError)
+      end
+    end
+
+    it "takes a list of arguments" do
+      eval("[1,2,3]&.first(2)").should == [1,2]
+    end
+
+    it "takes a block" do
+      eval("[1,2]&.map { |i| i * 2 }").should == [2, 4]
+    end
+
+    it "allows assignment methods" do
+      klass = Class.new do
+        attr_reader :foo
+        def foo=(val)
+          @foo = val
+          42
+        end
+      end
+      obj = klass.new
+
+      eval("obj&.foo = 3").should == 3
+      obj.foo.should == 3
+
+      obj = nil
+      eval("obj&.foo = 3").should == nil
+    end
+
+    it "allows assignment operators" do
+      klass = Class.new do
+        attr_accessor :m
+
+        def initialize
+          @m = 0
+        end
+      end
+
+      obj = klass.new
+
+      eval("obj&.m += 3")
+      obj.m.should == 3
+
+      obj = nil
+      eval("obj&.m += 3").should == nil
+    end
+
+    it "does not call the operator method lazily with an assignment operator" do
+      klass = Class.new do
+        attr_writer :foo
+        def foo
+          nil
+        end
+      end
+      obj = klass.new
+
+      lambda {
+        eval("obj&.foo += 3")
+      }.should raise_error(NoMethodError) { |e|
+        e.name.should == :+
+      }
+    end
+  end
+end