C#: Re-factor the ExternalFlow test.

Author: michaelnebel

csharp/ql/test/library-tests/dataflow/external-models/ExternalFlow.expected

@@ -1,3 +1,4 @@
+invalidModelRow
 edges
 | ExternalFlow.cs:9:27:9:38 | object creation of type Object : Object | ExternalFlow.cs:10:29:10:32 | access to local variable arg1 : Object |
 | ExternalFlow.cs:10:29:10:32 | access to local variable arg1 : Object | ExternalFlow.cs:10:18:10:33 | call to method StepArgRes |
@@ -162,7 +163,6 @@ nodes
 | ExternalFlow.cs:206:18:206:40 | call to method MixedFlowArgs | semmle.label | call to method MixedFlowArgs |
 | ExternalFlow.cs:206:38:206:39 | access to local variable o2 : Object | semmle.label | access to local variable o2 : Object |
 subpaths
-invalidModelRow
 #select
 | ExternalFlow.cs:10:18:10:33 | call to method StepArgRes | ExternalFlow.cs:9:27:9:38 | object creation of type Object : Object | ExternalFlow.cs:10:18:10:33 | call to method StepArgRes | $@ | ExternalFlow.cs:9:27:9:38 | object creation of type Object : Object | object creation of type Object : Object |
 | ExternalFlow.cs:18:18:18:24 | access to local variable argOut1 | ExternalFlow.cs:15:29:15:40 | object creation of type Object : Object | ExternalFlow.cs:18:18:18:24 | access to local variable argOut1 | $@ | ExternalFlow.cs:15:29:15:40 | object creation of type Object : Object | object creation of type Object : Object |

csharp/ql/test/library-tests/dataflow/external-models/ExternalFlow.ql

@@ -3,23 +3,23 @@
  */
 
 import csharp
-import DataFlow::PathGraph
 import semmle.code.csharp.dataflow.ExternalFlow
+import Taint::PathGraph
 import ModelValidation
 
-class Conf extends TaintTracking::Configuration {
-  Conf() { this = "ExternalFlow" }
+module TaintConfig implements DataFlow::ConfigSig {
+  predicate isSource(DataFlow::Node src) { src.asExpr() instanceof ObjectCreation }
 
-  override predicate isSource(DataFlow::Node src) { src.asExpr() instanceof ObjectCreation }
-
-  override predicate isSink(DataFlow::Node sink) {
+  predicate isSink(DataFlow::Node sink) {
     exists(MethodCall mc |
       mc.getTarget().hasName("Sink") and
       mc.getAnArgument() = sink.asExpr()
     )
   }
 }
 
+module Taint = TaintTracking::Global<TaintConfig>;
+
 /**
  * Simulate that methods with summaries are not included in the source code.
  * This is relevant for dataflow analysis using summaries tagged as generated.
@@ -28,6 +28,6 @@ private class MyMethod extends Method {
   override predicate fromSource() { none() }
 }
 
-from DataFlow::PathNode source, DataFlow::PathNode sink, Conf conf
-where conf.hasFlowPath(source, sink)
+from Taint::PathNode source, Taint::PathNode sink
+where Taint::flowPath(source, sink)
 select sink, source, sink, "$@", source, source.toString()