add 'language/and' spec

test/test-android/app/language/and_spec.rb

@@ -0,0 +1,64 @@
+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 "evalutes to the first condition not to be true" do
+    ("yes" && 1 && nil && true).should == nil
+    ("yes" && 1 && false && true).should == false
+  end
+
+  it "evalutes 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 "evalutes to the first condition not to be true" do
+    ("yes" and 1 and nil and true).should == nil
+    ("yes" and 1 and false and true).should == false
+  end
+
+  it "evalutes 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