Java: Add test.

java/ql/test/library-tests/dataflow/partial/A.java

@@ -0,0 +1,25 @@
+public class A {
+  static void sink(Object o) { }
+
+  static class Box {
+    public Object elem;
+  }
+
+  static Object src() { return new Object(); }
+
+  Box f1() {
+    Box b = new Box();
+    b.elem = src();
+    return b;
+  }
+
+  void f2() {
+    Box b = f1();
+    f3(b);
+  }
+
+  void f3(Box b) {
+    Box other = new Box();
+    sink(other.elem);
+  }
+}

java/ql/test/library-tests/dataflow/partial/test.expected

@@ -0,0 +1,6 @@
+| 0 | A.java:12:5:12:5 | b [post update] [elem, ... (1)] |
+| 0 | A.java:12:5:12:18 | ...=... [Object] |
+| 0 | A.java:13:12:13:12 | b [elem, ... (1)] |
+| 1 | A.java:17:13:17:16 | f1(...) [elem, ... (1)] |
+| 1 | A.java:18:8:18:8 | b [elem, ... (1)] |
+| 2 | A.java:21:11:21:15 | b [elem, ... (1)] |

java/ql/test/library-tests/dataflow/partial/test.ql

@@ -0,0 +1,17 @@
+import java
+import semmle.code.java.dataflow.DataFlow
+import DataFlow
+
+class Conf extends Configuration {
+  Conf() { this = "partial flow" }
+
+  override predicate isSource(Node n) { n.asExpr().(MethodAccess).getMethod().hasName("src") }
+
+  override predicate isSink(Node n) { n.asExpr().(Argument).getCall().getCallee().hasName("sink") }
+
+  override int explorationLimit() { result = 10 }
+}
+
+from PartialPathNode n, int dist
+where any(Conf c).hasPartialFlow(_, n, dist)
+select dist, n