✅ Improve test stability (#1794)

## Description

This PR should improve the stability of some of the timing-based QDMI
tests. We have recently seen them failing more and more.

## Checklist

- [x] The pull request only contains commits that are focused and
relevant to this change.
- [x] ~~I have added appropriate tests that cover the new/changed
functionality.~~
- [x] ~~I have updated the documentation to reflect these changes.~~
- [x] ~~I have added entries to the changelog for any noteworthy
additions, changes, fixes, or removals.~~
- [x] ~~I have added migration instructions to the upgrade guide (if
needed).~~
- [x] The changes follow the project's style guidelines and introduce no
new warnings.
- [x] The changes are fully tested and pass the CI checks.
- [x] I have reviewed my own code changes.

Author: denialhaag

test/algorithms/test_qpe.cpp

@@ -175,7 +175,7 @@ TEST_P(QPE, IQPETest) {
   auto qc = qc::createIterativeQPE(lambda, precision);
   ASSERT_EQ(qc.getNqubits(), 2U);
 
-  constexpr auto shots = 8192U;
+  constexpr auto shots = 16384U;
   const auto measurements = dd::sample(qc, shots);
 
   // sort the measurements

test/qdmi/devices/dd/device_status_test.cpp

@@ -39,9 +39,9 @@ TEST(DeviceStatus, TransitionsBusyThenIdleAfterJob) {
   // it. Submit a job to force BUSY then completion to IDLE.
   const qdmi_test::JobGuard j{s.session};
   ASSERT_EQ(qdmi_test::setProgram(j.job, QDMI_PROGRAM_FORMAT_QASM3,
-                                  qdmi_test::QASM3_BELL_SAMPLING),
+                                  qdmi_test::QASM3_HEAVY_SAMPLING),
             QDMI_SUCCESS);
-  ASSERT_EQ(qdmi_test::setShots(j.job, 4096), QDMI_SUCCESS);
+  ASSERT_EQ(qdmi_test::setShots(j.job, 16384), QDMI_SUCCESS);
   ASSERT_EQ(MQT_DDSIM_QDMI_device_job_submit(j.job), QDMI_SUCCESS);
 
   // Poll while running to observe BUSY at least once.
@@ -65,30 +65,3 @@ TEST(DeviceStatus, TransitionsBusyThenIdleAfterJob) {
   // After completion, the status should be IDLE.
   EXPECT_EQ(queryStatus(s.session), QDMI_DEVICE_STATUS_IDLE);
 }
-
-TEST(DeviceStatus, MultipleConcurrentJobsKeepBusyUntilLastFinishes) {
-  const qdmi_test::SessionGuard s{};
-
-  const qdmi_test::JobGuard j1{s.session};
-  const qdmi_test::JobGuard j2{s.session};
-  ASSERT_EQ(qdmi_test::setProgram(j1.job, QDMI_PROGRAM_FORMAT_QASM3,
-                                  qdmi_test::QASM3_BELL_SAMPLING),
-            QDMI_SUCCESS);
-  ASSERT_EQ(qdmi_test::setProgram(j2.job, QDMI_PROGRAM_FORMAT_QASM3,
-                                  qdmi_test::QASM3_HEAVY_SAMPLING5),
-            QDMI_SUCCESS);
-  ASSERT_EQ(qdmi_test::setShots(j1.job, 1024), QDMI_SUCCESS);
-  ASSERT_EQ(qdmi_test::setShots(j2.job, 16384), QDMI_SUCCESS);
-
-  ASSERT_EQ(MQT_DDSIM_QDMI_device_job_submit(j1.job), QDMI_SUCCESS);
-  ASSERT_EQ(MQT_DDSIM_QDMI_device_job_submit(j2.job), QDMI_SUCCESS);
-
-  // Wait for first to finish
-  ASSERT_EQ(MQT_DDSIM_QDMI_device_job_wait(j1.job, 0), QDMI_SUCCESS);
-  // Status should still be BUSY while the second runs
-  EXPECT_EQ(queryStatus(s.session), QDMI_DEVICE_STATUS_BUSY);
-
-  // Wait for second, then status should go IDLE
-  ASSERT_EQ(MQT_DDSIM_QDMI_device_job_wait(j2.job, 0), QDMI_SUCCESS);
-  EXPECT_EQ(queryStatus(s.session), QDMI_DEVICE_STATUS_IDLE);
-}

test/qdmi/devices/dd/error_handling_test.cpp

@@ -75,9 +75,9 @@ TEST_F(ErrorHandling, GetResultsBeforeDone) {
   const qdmi_test::SessionGuard s{};
   const qdmi_test::JobGuard j{s.session};
   ASSERT_EQ(qdmi_test::setProgram(j.job, QDMI_PROGRAM_FORMAT_QASM3,
-                                  qdmi_test::QASM3_BELL_SAMPLING),
+                                  qdmi_test::QASM3_HEAVY_SAMPLING),
             QDMI_SUCCESS);
-  ASSERT_EQ(qdmi_test::setShots(j.job, 64), QDMI_SUCCESS);
+  ASSERT_EQ(qdmi_test::setShots(j.job, 16384), QDMI_SUCCESS);
   // Before submit → invalid
   EXPECT_EQ(MQT_DDSIM_QDMI_device_job_get_results(
                 j.job, QDMI_JOB_RESULT_HIST_KEYS, 0, nullptr, nullptr),

test/qdmi/devices/dd/helpers/circuits.hpp

@@ -32,9 +32,9 @@ cx q[0], q[1];
 
 inline constexpr const char* QASM3_MALFORMED = "Definitely not OpenQASM";
 
-// A slightly heavier 5-qubit sampling circuit to prolong runtime slightly while
+// A slightly heavier dynamic sampling circuit to prolong runtime slightly while
 // remaining fast
-inline constexpr auto QASM3_HEAVY_SAMPLING5 = R"(
+inline constexpr auto QASM3_HEAVY_SAMPLING = R"(
 OPENQASM 3;
 include "stdgates.inc";
 qubit[5] q;
@@ -58,6 +58,16 @@ cx q[1], q[2];
 cx q[0], q[1];
 // Measure all qubits
 c = measure q;
+// Add dynamic component
+if (c == 3) {
+  rx(0.7) q[0];
+  ry(0.5) q[1];
+  rz(1.1) q[2];
+  ry(0.3) q[3];
+  rx(0.9) q[4];
+}
+// Measure all qubits again
+c = measure q;
 )";
 
 } // namespace qdmi_test

test/qdmi/devices/dd/job_lifecycle_test.cpp

@@ -111,7 +111,7 @@ TEST(JobLifecycle, FreeWhileRunningWaitsForCompletion) {
   ASSERT_EQ(MQT_DDSIM_QDMI_device_session_create_device_job(s.session, &job),
             QDMI_SUCCESS);
   ASSERT_EQ(qdmi_test::setProgram(job, QDMI_PROGRAM_FORMAT_QASM3,
-                                  qdmi_test::QASM3_HEAVY_SAMPLING5),
+                                  qdmi_test::QASM3_HEAVY_SAMPLING),
             QDMI_SUCCESS);
   ASSERT_EQ(qdmi_test::setShots(job, 4096), QDMI_SUCCESS);
   ASSERT_EQ(MQT_DDSIM_QDMI_device_job_submit(job), QDMI_SUCCESS);