ruby: add test of rb/uninitialized-local-variable

Author: yoff

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

@@ -0,0 +1,6 @@
+| UninitializedLocal.rb:12:5:12:5 | m | Local variable $@ may be used before it is initialized. | UninitializedLocal.rb:8:9:8:9 | m | m |
+| UninitializedLocal.rb:17:18:17:18 | a | Local variable $@ may be used before it is initialized. | UninitializedLocal.rb:17:9:17:9 | a | a |
+| UninitializedLocal.rb:24:5:24:5 | b | Local variable $@ may be used before it is initialized. | UninitializedLocal.rb:21:9:21:9 | b | b |
+| UninitializedLocal.rb:25:5:25:5 | b | Local variable $@ may be used before it is initialized. | UninitializedLocal.rb:21:9:21:9 | b | b |
+| UninitializedLocal.rb:35:15:35:15 | a | Local variable $@ may be used before it is initialized. | UninitializedLocal.rb:31:13:31:13 | a | a |
+| UninitializedLocal.rb:36:5:36:5 | a | Local variable $@ may be used before it is initialized. | UninitializedLocal.rb:31:13:31:13 | a | a |

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

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

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

@@ -0,0 +1,37 @@
+def m
+    puts "m"
+end
+
+def foo
+    m # calls m above
+    if false
+        m = 0
+        m # reads local variable m
+    else
+    end
+    m  #$ Alert
+    m2 # undefined local variable or method 'm2' for main (NameError)
+end
+
+def test_guards
+    if (a = 3 && a)  #$ SPURIOUS: Alert
+        a
+    end
+    if false
+        b = 0
+    end
+    b.nil?
+    b || 0  #$ SPURIOUS: Alert
+    b&.m  #$ SPURIOUS: Alert
+end
+
+def test_loop
+    begin
+        if false
+            a = 0
+        else
+            set_a
+        end   
+    end until a  #$ SPURIOUS: Alert
+    a  #$ SPURIOUS: Alert
+end