Added tests for grouping

Signed-off-by: Thien Nguyen <nguyentm@ornl.gov>

quantum/observable/pauli/PauliOperator.cpp

@@ -277,7 +277,7 @@ PauliOperator::observe(std::shared_ptr<CompositeInstruction> function, const Het
   }
 
   // For this, we require the Accelerator info:
-  if (grouping_options.pointerLikeExists<Accelerator>("accelerator")) {
+  if (!grouping_options.pointerLikeExists<Accelerator>("accelerator")) {
     xacc::error("'accelerator' is required for Observable grouping");
   }
   auto qpu = grouping_options.getPointerLike<Accelerator>("accelerator");

quantum/observable/pauli/tests/PauliOperatorTester.cpp

@@ -490,6 +490,29 @@ TEST(PauliOperatorTester, checkNormalize) {
 
 }
 
+TEST(PauliOperatorTester, checkGroupingQaoa) {
+  PauliOperator op;
+  op.fromString("(0, -1) Z0 Z1 + (0, -1) Z1 Z2 + (0, -1) Z2 Z0");
+  std::cout << op.toString() << "\n";
+  auto qpu = xacc::getAccelerator("qpp", {{"shots", 1024}});
+  auto gateRegistry = xacc::getService<xacc::IRProvider>("quantum");
+  auto f = gateRegistry->createComposite("f");
+  auto h0 = gateRegistry->createInstruction("H", 0);
+  auto h1 = gateRegistry->createInstruction("H", 1);
+  auto h2 = gateRegistry->createInstruction("H", 2);
+  f->addInstructions({h0, h1, h2});
+  auto observed = op.observe(f, {{"accelerator", qpu}});
+  EXPECT_EQ(observed.size(), 1);
+
+  // Check non-commute as well:
+  PauliOperator op_non_commute;
+  op_non_commute.fromString("(0, -1) Z0 Z1 + (0, -1) Z1 Z2 + (0, -1) Z2 X0");
+  std::cout << op_non_commute.toString() << "\n";
+  auto observed_non_commute = op_non_commute.observe(f, {{"accelerator", qpu}});
+  // Three terms:
+  EXPECT_EQ(observed_non_commute.size(), 3);
+}
+
 int main(int argc, char **argv) {
   xacc::Initialize(argc, argv);
   ::testing::InitGoogleTest(&argc, argv);

quantum/plugins/qpp/accelerator/QppAccelerator.hpp

@@ -28,6 +28,7 @@ public:
     virtual void initialize(const HeterogeneousMap& params = {}) override;
     virtual void updateConfiguration(const HeterogeneousMap& config) override {initialize(config);};
     virtual const std::vector<std::string> configurationKeys() override { return {}; }
+    virtual HeterogeneousMap getProperties() override { return {{"shots", m_shots}}; }
     virtual BitOrder getBitOrder() override {return BitOrder::LSB;}
     virtual void execute(std::shared_ptr<AcceleratorBuffer> buffer, const std::shared_ptr<CompositeInstruction> compositeInstruction) override;
     virtual void execute(std::shared_ptr<AcceleratorBuffer> buffer, const std::vector<std::shared_ptr<CompositeInstruction>> compositeInstructions) override;