ruby: add tests

ruby/ql/test/query-tests/variables/DeadStoreOfLocal/DeadStoreOfLocal.expected

@@ -0,0 +1,4 @@
+| DeadStoreOfLocal.rb:2:5:2:5 | y | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.rb:2:5:2:5 | y | y |
+| DeadStoreOfLocal.rb:14:9:14:9 | x | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.rb:8:5:8:5 | x | x |
+| DeadStoreOfLocal.rb:21:5:21:5 | x | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.rb:21:5:21:5 | x | x |
+| TestTemplate.rb:9:1:9:1 | x | This assignment to $@ is useless, since its value is never read. | TestTemplate.rb:9:1:9:1 | x | x |

ruby/ql/test/query-tests/variables/DeadStoreOfLocal/DeadStoreOfLocal.qlref

@@ -0,0 +1,2 @@
+query: queries/variables/DeadStoreOfLocal.ql
+postprocess: utils/test/InlineExpectationsTestQuery.ql

ruby/ql/test/query-tests/variables/DeadStoreOfLocal/DeadStoreOfLocal.rb

@@ -0,0 +1,36 @@
+def test_basic(x)
+    y = x  #$ Alert
+    y = x + 2
+    return y
+end
+
+def test_retry
+    x = 0
+    begin
+        if x == 0
+            raise "error"
+        end
+    rescue
+        x = 2  #$ SPURIOUS: Alert
+        retry
+    end
+    return 42
+end
+
+def test_binding
+    x = 4  #$ SPURIOUS: Alert
+    return binding
+end
+
+class Sup
+    def m(x)
+        print(x + 1)
+    end
+end
+  
+class Sub < Sup
+    def m(y)
+        y = 3  # OK - the call to `super` sees the value of y
+        super
+    end
+end

ruby/ql/test/query-tests/variables/DeadStoreOfLocal/TestTemplate.rb

@@ -0,0 +1,10 @@
+# -*- coding: utf-8 -*-
+require 'erb'
+
+template = ERB.new <<EOF
+<%#-*- coding: Big5 -*-%>
+  \_\_ENCODING\_\_ is <%= \_\_ENCODING\_\_ %>.
+  x is <%= x %>.
+EOF
+x = 5  #$ SPURIOUS: Alert
+puts template.result