Ruby: CFG: add test case

ruby/ql/test/library-tests/controlflow/graph/Cfg.expected

@@ -1010,7 +1010,7 @@ case.rb:
 #-----|  -> value
 
 #   69| case_match_various
-#-----|  -> exit case.rb (normal)
+#-----|  -> case_match_guard_no_else
 
 #   69| exit case_match_various
 
@@ -1311,6 +1311,51 @@ case.rb:
 #-----| raise -> exit case_match_various (abnormal)
 #-----| match -> exit case_match_various (normal)
 
+#   95| enter case_match_guard_no_else
+#-----|  -> value
+
+#   95| case_match_guard_no_else
+#-----|  -> exit case.rb (normal)
+
+#   95| exit case_match_guard_no_else
+
+#   95| exit case_match_guard_no_else (abnormal)
+#-----|  -> exit case_match_guard_no_else
+
+#   95| exit case_match_guard_no_else (normal)
+#-----|  -> exit case_match_guard_no_else
+
+#   95| value
+#-----|  -> case ...
+
+#   96| case ...
+#-----|  -> value
+
+#   96| value
+#-----|  -> in ... then ...
+
+#   97| in ... then ...
+#-----|  -> x
+
+#   97| x
+#-----| match -> x
+
+#   97| ... == ...
+#-----| true -> 6
+#-----| raise -> exit case_match_guard_no_else (abnormal)
+
+#   97| x
+#-----|  -> 5
+
+#   97| 5
+#-----|  -> ... == ...
+
+#   97| then ...
+#-----|  -> exit case_match_guard_no_else (normal)
+
+#   97| 6
+#-----|  -> then ...
+
 cfg.html.erb:
 #    5| enter cfg.html.erb
 #-----|  -> @title

ruby/ql/test/library-tests/controlflow/graph/Nodes.expected

@@ -90,6 +90,7 @@ positionalArguments
 | case.rb:77:8:77:18 | call to [] | case.rb:77:11:77:13 | :"foo" |
 | case.rb:77:8:77:18 | call to [] | case.rb:77:15:77:17 | :"bar" |
 | case.rb:85:15:85:21 | ... == ... | case.rb:85:20:85:21 | 10 |
+| case.rb:97:13:97:18 | ... == ... | case.rb:97:18:97:18 | 5 |
 | cfg.html.erb:6:9:6:58 | call to stylesheet_link_tag | cfg.html.erb:6:29:6:41 | "application" |
 | cfg.html.erb:6:9:6:58 | call to stylesheet_link_tag | cfg.html.erb:6:44:6:58 | Pair |
 | cfg.html.erb:12:11:12:33 | call to link_to | cfg.html.erb:12:19:12:21 | "A" |

ruby/ql/test/library-tests/controlflow/graph/case.rb

@@ -91,3 +91,9 @@ def case_match_various value
     in (0 | "" | [] | {})
   end
 end
+
+def case_match_guard_no_else value
+  case value
+    in x if x == 5 then 6
+  end
+end