start rubymotion-specific String specs

test/test-android/app/main.rb

@@ -14,7 +14,7 @@ class ShouldResult < Java::Lang::Object
 
   def ==(x)
     if (@obj == x) != @res
-      puts "Expectation failed (expected `#{@obj}' == `#{x}')"
+      puts "Expectation failed (expected `#{@obj}' (#{@obj.class}) == `#{x}' (#{x.class}))"
       $expectations_failures += 1
     end
     $expectations_total += 1

test/test-android/app/rubymotion/string_spec.rb

@@ -0,0 +1,13 @@
+describe "Strings" do
+  it "are based on com.rubymotion.String" do
+    'foo'.class.should == String
+    'foo'.class.inspect.should == 'com.rubymotion.String'
+  end
+
+  it "can be passed to Java methods expecting a java.lang.CharSequence" do
+    str_builder = Java::Lang::StringBuilder.new
+    str_builder.append('hello')
+    str_builder.append(' world')
+    str_builder.toString.should == 'hello world'
+  end
+end