fixed new flatten operation function, added first test structure

Author: M-J-Hochreiter

src/algorithms/StatePreparation.cpp

@@ -150,7 +150,7 @@ template <typename T>
     multiplexer.cx(0, static_cast<Qubit>(localNumQubits - 1));
   }
 
-  CircuitOptimizer::flattenOperations(multiplexer);
+  CircuitOptimizer::flattenOperations(multiplexer, false);
   return multiplexer;
 }
 
@@ -277,7 +277,7 @@ auto createStatePreparationCircuit(
   QuantumComputation toZeroCircuit = gatesToUncompute(amplitudes, numQubits);
 
   // invert circuit
-  CircuitOptimizer::flattenOperations(toZeroCircuit);
+  CircuitOptimizer::flattenOperations(toZeroCircuit, false);
   toZeroCircuit.invert();
 
   return toZeroCircuit;

test/algorithms/test_statepreparation.cpp

@@ -0,0 +1,44 @@
+#include "Definitions.hpp"
+#include "algorithms/StatePreparation.hpp"
+#include "dd/Package.hpp"
+#include "ir/QuantumComputation.hpp"
+
+#include <cmath>
+#include <complex>
+#include <gtest/gtest.h>
+#include <sstream>
+#include <string>
+#include <vector>
+
+class StatePreparation
+    : public testing::TestWithParam<std::vector<std::complex<double>>> {
+protected:
+  std::vector<std::complex<double>> amplitudes{};
+
+  void TearDown() override {}
+  void SetUp() override { amplitudes = GetParam(); }
+};
+
+INSTANTIATE_TEST_SUITE_P(
+    StatePreparation, StatePreparation,
+    testing::Values(std::vector{std::complex{1 / std::sqrt(2)},
+                                std::complex{-1 / std::sqrt(2)}},
+                    std::vector<std::complex<double>>{
+                        0, std::complex{1 / std::sqrt(2)},
+                        std::complex{-1 / std::sqrt(2)}, 0}),
+    [](const testing::TestParamInfo<StatePreparation::ParamType>& inf) {
+      const std::vector<std::complex<double>> vector = inf.param;
+      std::stringstream ss{};
+      ss << "State Preparation with amplitudes: [";
+      for (const auto cmplx : vector) {
+        ss << ", (" + std::to_string(cmplx.real()) + "," +
+                  std::to_string(cmplx.imag()) + ")";
+      }
+      return ss.str();
+    });
+
+TEST_P(StatePreparation, StatePreparationCircuitSimulation) {
+  ASSERT_NO_THROW({ auto qc = qc::createStatePreparationCircuit(amplitudes); });
+}
+
+TEST_P(StatePreparation, StatePreparationCircuit) {}