add Struct tests

test/t/struct.rb

@@ -9,3 +9,53 @@ assert('Struct superclass', '15.2.18.2') do
   Struct.superclass == Object
 end
 
+assert('Struct.new', '15.2.18.3.1') do
+  c = Struct.new(:m1, :m2)
+  c.superclass == Struct and
+    c.members == [:m1,:m2]
+end
+
+assert('Struct#[]', '15.2.18.4.2') do
+  c = Struct.new(:m1, :m2)
+  cc = c.new(1,2)
+  cc[:m1] == 1 and cc["m2"] == 2
+end
+
+assert('Struct#[]=', '15.2.18.4.3') do
+  c = Struct.new(:m1, :m2)
+  cc = c.new(1,2)
+  cc[:m1] = 3
+  cc[:m1] == 3
+end
+
+assert('Struct#each', '15.2.18.4.4') do
+  c = Struct.new(:m1, :m2)
+  cc = c.new(1,2)
+  a = []
+  cc.each{|x|
+    a << x
+  }
+  a[0] == 1 and a[1] == 2
+end
+
+assert('Struct#each_pair', '15.2.18.4.5') do
+  c = Struct.new(:m1, :m2)
+  cc = c.new(1,2)
+  a = []
+  cc.each_pair{|k,v|
+    a << [k,v]
+  }
+  a[0] == [:m1, 1] and a[1] == [:m2, 2]
+end
+
+assert('Struct#members', '15.2.18.4.6') do
+  c = Struct.new(:m1, :m2)
+  cc = c.new(1,2)
+  cc.members == [:m1,:m2]
+end
+
+assert('Struct#select', '15.2.18.4.7') do
+  c = Struct.new(:m1, :m2)
+  cc = c.new(1,2)
+  cc.select{|v| v % 2 == 0} == [2]
+end