fix(engine): expose session close

app/src/main/java/org/openobservatory/ooniprobe/test/TestAsyncTask.java

@@ -197,6 +197,9 @@ private void downloadURLs() {
                 currentTest.setMax_runtime(app.getPreferenceManager().getMaxRuntime());
             }
             publishProgress(URL);
+
+            // we close the session to ensure that we have no running circumvention tunnels
+            session.close();
         } catch (Exception e) {
             e.printStackTrace();
             ThirdPartyServices.logException(e);

engine/src/main/java/org/openobservatory/engine/OONISession.java

@@ -38,4 +38,7 @@ public interface OONISession {
     OONIRunDescriptor getLatestOONIRunLink(OONIContext ctx, String probeServicesURL, long id) throws Exception;
 
     OONIRunRevisions getOONIRunLinkRevisions(@Nullable OONIContext ooniContext, @NotNull String probeServicesURL, long runId) throws Exception ;
+
+    /** close closes the session along with any running circumvention tunnels */
+    void close() throws Exception;
 }

engine/src/main/java/org/openobservatory/engine/PESession.java

@@ -58,4 +58,8 @@ public OONIRunRevisions getOONIRunLinkRevisions(OONIContext ooniContext, @NotNul
 
         return revisions;
     }
+
+    public void close() throws Exception {
+        session.close();
+    }
 }