Increase test coverage of mruby-struct

mrbgems/mruby-struct/test/struct.rb

@@ -73,5 +73,33 @@ if Object.const_defined?(:Struct)
     cc = c.new(1,2)
     cc.select{|v| v % 2 == 0} == [2]
   end
-end
 
+  assert('large struct') do
+    c = Struct.new(:m1, :m2, :m3, :m4, :m5, :m6, :m7, :m8, :m9, :m10, :m11, :m12, :m13)
+    cc = c.new(1,2,3,4,5,6,7,8,9,10,11,12,13)
+    assert_equal 1, cc.m1
+    assert_equal 2, cc.m2
+    assert_equal 3, cc.m3
+    assert_equal 4, cc.m4
+    assert_equal 5, cc.m5
+    assert_equal 6, cc.m6
+    assert_equal 7, cc.m7
+    assert_equal 8, cc.m8
+    assert_equal 9, cc.m9
+    assert_equal 10, cc.m10
+    assert_equal 13, cc.m13
+  end
+
+  assert('wrong struct arg count') do
+    c = Struct.new(:m1)
+    assert_raise ArgumentError do
+      cc = c.new(1,2,3)
+    end
+  end
+
+  assert('struct inspect') do
+    c = Struct.new(:m1, :m2, :m3, :m4, :m5)
+    cc = c.new(1,2,3,4,5)
+    assert_equal "#<struct #{c.inspect} m1=1, m2=2, m3=3, m4=4, m5=5>", cc.inspect
+  end
+end