From 1fc6ecfe9da8b0b11df833546870643d5529a6d1 Mon Sep 17 00:00:00 2001
From: Tyson Jones <tyson.jones.input@gmail.com>
Date: Tue, 6 May 2025 00:05:25 +0200
Subject: [PATCH] added calcRealAmpSum tests

---
 tests/unit/calculations.cpp | 41 +++++++++++++++++++++++++++++++++++++
 tests/utils/linalg.cpp      | 31 ++++++++++++++++++++++++++++
 tests/utils/linalg.hpp      |  3 +++
 3 files changed, 75 insertions(+)

diff --git a/tests/unit/calculations.cpp b/tests/unit/calculations.cpp
index 3cbe22c9f..8c9e6c653 100644
--- a/tests/unit/calculations.cpp
+++ b/tests/unit/calculations.cpp
@@ -156,6 +156,47 @@ void TEST_ON_CACHED_QUREG_AND_MATRIX(quregCache quregs, matrixCache matrices, au
 
 
 
+TEST_CASE( "calcRealAmpSum", TEST_CATEGORY ) {
+
+    SECTION( LABEL_CORRECTNESS ) {
+
+        // The boilerplate for testing a function differs
+        // greatly depending on what the function does;
+        // this function is trivial so has a simple test,
+        // re-using the existing TEST_ALL_QUREGS() macro.
+        // This macro invokes the below RHS expressions
+        // passing substitutions of the LHS expressions
+        // with Quregs (statevector or density matrix)
+        // and reference objects (qvector or qmatrix), for
+        // every possible deployment (i.e. multithreading,
+        // GPU-acceleration, distribution, hybrids, etc).
+
+        TEST_ALL_QUREGS(
+            qureg, calcRealAmpSum(qureg),
+            refer, std::real(getTotal(refer))
+        );
+    }
+
+    SECTION( LABEL_VALIDATION ) {
+
+        SECTION( "qureg uninitialised" ) {
+
+            // prepare an un-initialised qureg
+            Qureg qureg;
+
+            // manually mangle the fields for validation
+            // to detect, since the default values are
+            // undefined behaviour and might not trigger
+            // (e.g. compiler could re-use a valid Qureg)
+            qureg.numQubits = -123;
+
+            REQUIRE_THROWS_WITH( calcRealAmpSum(qureg), ContainsSubstring("invalid Qureg") );
+        }
+    }
+}
+
+
+
 TEST_CASE( "calcExpecPauliStr", TEST_CATEGORY ) {
 
     SECTION( LABEL_CORRECTNESS ) {
diff --git a/tests/utils/linalg.cpp b/tests/utils/linalg.cpp
index f4686fc44..716b14b6e 100644
--- a/tests/utils/linalg.cpp
+++ b/tests/utils/linalg.cpp
@@ -107,6 +107,37 @@ int getNumPermutations(int n, int k) {
 
 
 
+/*
+ * NONSENSE PR OPERATIONS
+ */
+
+
+qcomp getTotal(qvector in) {
+
+    qcomp out = 0;
+
+    // no compensated summation
+    for (auto& elem : in)
+        out += elem;
+
+    return out;
+}
+
+
+qcomp getTotal(qmatrix in) {
+
+    qcomp out = 0;
+
+    // no compensated summation
+    for (auto& row : in)
+        for (auto& elem : row)
+            out += elem;
+
+    return out;
+}
+
+
+
 /*
  * VECTOR OPERATIONS
  */
diff --git a/tests/utils/linalg.hpp b/tests/utils/linalg.hpp
index 87cd116b5..ebca2b4c5 100644
--- a/tests/utils/linalg.hpp
+++ b/tests/utils/linalg.hpp
@@ -29,6 +29,9 @@ qindex setBitAt(qindex num, int ind, int bit);
 qindex setBitsAt(qindex num, vector<int> inds, qindex bits);
 qindex getPow2(int);
 
+qcomp getTotal(qvector);
+qcomp getTotal(qmatrix);
+
 qreal getSum(vector<qreal> vec);
 qcomp getSum(qvector);
 qvector getNormalised(qvector);