tests for "case" expression.

test/t/syntax.rb

@@ -42,6 +42,98 @@ assert('Abbreviated variable assignment', '11.4.2.3.2') do
   assert_equal 3, c
 end
 
+assert('case expression', '11.5.2.2.4') do
+  # case-expression-with-expression, one when-clause
+  x = 0
+  case "a"
+  when "a"
+    x = 1
+  end
+  assert_equal 1, x
+
+  # case-expression-with-expression, multiple when-clauses
+  x = 0
+  case "b"
+  when "a"
+    x = 1
+  when "b"
+    x = 2
+  end
+  assert_equal 2, x
+
+  # no matching when-clause
+  x = 0
+  case "c"
+  when "a"
+    x = 1
+  when "b"
+    x = 2
+  end
+  assert_equal 0, x
+
+  # case-expression-with-expression, one when-clause and one else-clause
+  a = 0
+  case "c"
+  when "a"
+    x = 1
+  else
+    x = 3
+  end
+  assert_equal 3, x
+
+  # case-expression-without-expression, one when-clause
+  x = 0
+  case
+  when true
+    x = 1
+  end
+  assert_equal 1, x
+
+  # case-expression-without-expression, multiple when-clauses
+  x = 0
+  case
+  when 0 == 1
+    x = 1
+  when 1 == 1
+    x = 2
+  end
+  assert_equal 2, x
+
+  # case-expression-without-expression, one when-clause and one else-clause
+  x = 0
+  case
+  when 0 == 1
+    x = 1
+  else
+    x = 3
+  end
+  assert_equal 3, x
+
+  # multiple when-arguments
+  x = 0
+  case 4
+  when 1, 3, 5
+    x = 1
+  when 2, 4, 6
+    x = 2
+  end
+  assert_equal 2, x
+
+  # when-argument with splatting argument
+  x = :integer
+  odds  = [ 1, 3, 5, 7, 9 ]
+  evens = [ 2, 4, 6, 8 ]
+  case 5
+  when *odds
+    x = :odd
+  when *evens
+    x = :even
+  end
+  assert_equal :odd, x
+
+  true
+end
+
 assert('Nested const reference') do
   module Syntax4Const
     CONST1 = "hello world"