Add in-tree mspec and ruby/spec

* For easier modifications of ruby/spec by MRI developers.
* .gitignore: track changes under spec.
* spec/mspec, spec/rubyspec: add in-tree mspec and ruby/spec.
  These files can therefore be updated like any other file in MRI.
  Instructions are provided in spec/README.
  [Feature #13156] [ruby-core:79246]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58595 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 80 insertions, 0 deletions

diff --git a/spec/rubyspec/language/and_spec.rb b/spec/rubyspec/language/and_spec.rb
new file mode 100644
index 0000000000..e084fd3cef
--- /dev/null
+++ b/spec/rubyspec/language/and_spec.rb
@@ -0,0 +1,80 @@
+require File.expand_path('../../spec_helper', __FILE__)
+
+describe "The '&&' statement" do
+
+  it "short-circuits evaluation at the first condition to be false" do
+    x = nil
+    true && false && x = 1
+    x.should be_nil
+  end
+
+  it "evaluates to the first condition not to be true" do
+    value = nil
+    (value && nil).should == nil
+    (value && false).should == nil
+    value = false
+    (value && nil).should == false
+    (value && false).should == false
+
+    ("yes" && 1 && nil && true).should == nil
+    ("yes" && 1 && false && true).should == false
+  end
+
+  it "evaluates to the last condition if all are true" do
+    ("yes" && 1).should == 1
+    (1 && "yes").should == "yes"
+  end
+
+  it "evaluates the full set of chained conditions during assignment" do
+    x, y = nil
+    x = 1 && y = 2
+    # "1 && y = 2" is evaluated and then assigned to x
+    x.should == 2
+  end
+
+  it "treats empty expressions as nil" do
+    (() && true).should be_nil
+    (true && ()).should be_nil
+    (() && ()).should be_nil
+  end
+
+end
+
+describe "The 'and' statement" do
+  it "short-circuits evaluation at the first condition to be false" do
+    x = nil
+    true and false and x = 1
+    x.should be_nil
+  end
+
+  it "evaluates to the first condition not to be true" do
+    value = nil
+    (value and nil).should == nil
+    (value and false).should == nil
+    value = false
+    (value and nil).should == false
+    (value and false).should == false
+
+    ("yes" and 1 and nil and true).should == nil
+    ("yes" and 1 and false and true).should == false
+  end
+
+  it "evaluates to the last condition if all are true" do
+    ("yes" and 1).should == 1
+    (1 and "yes").should == "yes"
+  end
+
+  it "when used in assignment, evaluates and assigns expressions individually" do
+    x, y = nil
+    x = 1 and y = 2
+    # evaluates (x=1) and (y=2)
+    x.should == 1
+  end
+
+  it "treats empty expressions as nil" do
+    (() and true).should be_nil
+    (true and ()).should be_nil
+    (() and ()).should be_nil
+  end
+
+end