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+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