1 files changed, 38 insertions, 12 deletions

diff --git a/vespalib/src/tests/datastore/buffer_type/buffer_type_test.cpp b/vespalib/src/tests/datastore/buffer_type/buffer_type_test.cpp
index 96d94e9a71b..b5a0212528b 100644
--- a/vespalib/src/tests/datastore/buffer_type/buffer_type_test.cpp
+++ b/vespalib/src/tests/datastore/buffer_type/buffer_type_test.cpp
@@ -14,6 +14,7 @@ struct Setup {
     uint32_t  _minArrays;
     ElemCount _usedElems;
     ElemCount _neededElems;
+    ElemCount _deadElems;
     uint32_t  _bufferId;
     float     _allocGrowFactor;
     bool      _resizing;
@@ -21,6 +22,7 @@ struct Setup {
         : _minArrays(0),
           _usedElems(0),
           _neededElems(0),
+          _deadElems(0),
           _bufferId(1),
           _allocGrowFactor(0.5),
           _resizing(false)
@@ -33,25 +35,40 @@ struct Setup {
 };
 
 struct Fixture {
-    Setup         setup;
+    std::vector<Setup> setups;
     IntBufferType bufferType;
-    ElemCount     deadElems;
     int buffer[ARRAYS_SIZE];
     Fixture(const Setup &setup_)
-        : setup(setup_),
-          bufferType(ARRAYS_SIZE, setup._minArrays, MAX_ARRAYS, NUM_ARRAYS_FOR_NEW_BUFFER, setup._allocGrowFactor),
-          deadElems(0),
+        : setups(),
+          bufferType(ARRAYS_SIZE, setup_._minArrays, MAX_ARRAYS, NUM_ARRAYS_FOR_NEW_BUFFER, setup_._allocGrowFactor),
           buffer()
-    {}
+    {
+        setups.reserve(4);
+        setups.push_back(setup_);
+    }
     ~Fixture() {
-        bufferType.onHold(&setup._usedElems);
-        bufferType.onFree(setup._usedElems);
+        for (auto& setup : setups) {
+            bufferType.onHold(&setup._usedElems);
+            bufferType.onFree(setup._usedElems);
+        }
+    }
+    Setup& curr_setup() {
+        return setups.back();
+    }
+    void add_setup(const Setup& setup_in) {
+        // The buffer type stores pointers to ElemCount (from Setup) and we must ensure these do not move in memory.
+        assert(setups.size() < setups.capacity());
+        setups.push_back(setup_in);
     }
     void onActive() {
-        bufferType.onActive(setup._bufferId, &setup._usedElems, deadElems, &buffer[0]);
+        bufferType.onActive(curr_setup()._bufferId, &curr_setup()._usedElems, curr_setup()._deadElems, &buffer[0]);
     }
     size_t arraysToAlloc() {
-        return bufferType.calcArraysToAlloc(setup._bufferId, setup._neededElems, setup._resizing);
+        return bufferType.calcArraysToAlloc(curr_setup()._bufferId, curr_setup()._neededElems, curr_setup()._resizing);
+    }
+    void assertArraysToAlloc(size_t exp) {
+        onActive();
+        EXPECT_EQUAL(exp, arraysToAlloc());
     }
 };
 
@@ -59,8 +76,7 @@ void
 assertArraysToAlloc(size_t exp, const Setup &setup)
 {
     Fixture f(setup);
-    f.onActive();
-    EXPECT_EQUAL(exp, f.arraysToAlloc());
+    f.assertArraysToAlloc(exp);
 }
 
 TEST("require that complete arrays are allocated")
@@ -113,4 +129,14 @@ TEST("require that arrays to alloc is capped to min arrays")
     TEST_DO(assertArraysToAlloc(17, Setup().used(34 * 4).needed(4).minArrays(16)));
 }
 
+TEST("arrays to alloc considers used elements across all active buffers")
+{
+    Fixture f(Setup().used(6 * 4));
+    f.assertArraysToAlloc(6 * 0.5);
+    f.add_setup(Setup().used(8 * 4));
+    f.assertArraysToAlloc((6 + 8) * 0.5);
+    f.add_setup(Setup().used(10 * 4));
+    f.assertArraysToAlloc((6 + 8 + 10) * 0.5);
+}
+
 TEST_MAIN() { TEST_RUN_ALL(); }