1 files changed, 116 insertions, 0 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
new file mode 100644
index 00000000000..6a51b9192ce
--- /dev/null
+++ b/vespalib/src/tests/datastore/buffer_type/buffer_type_test.cpp
@@ -0,0 +1,116 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include <vespa/vespalib/datastore/buffer_type.h>
+#include <vespa/vespalib/testkit/testapp.h>
+
+using namespace search::datastore;
+
+using IntBufferType = BufferType<int>;
+constexpr uint32_t ARRAYS_SIZE(4);
+constexpr uint32_t MAX_ARRAYS(128);
+constexpr uint32_t NUM_ARRAYS_FOR_NEW_BUFFER(0);
+
+struct Setup {
+    uint32_t _minArrays;
+    size_t _usedElems;
+    size_t _neededElems;
+    uint32_t _bufferId;
+    float _allocGrowFactor;
+    bool _resizing;
+    Setup()
+        : _minArrays(0),
+          _usedElems(0),
+          _neededElems(0),
+          _bufferId(1),
+          _allocGrowFactor(0.5),
+          _resizing(false)
+    {}
+    Setup &minArrays(uint32_t value) { _minArrays = value; return *this; }
+    Setup &used(size_t value) { _usedElems = value; return *this; }
+    Setup &needed(size_t value) { _neededElems = value; return *this; }
+    Setup &bufferId(uint32_t value) { _bufferId = value; return *this; }
+    Setup &resizing(bool value) { _resizing = value; return *this; }
+};
+
+struct Fixture {
+    Setup setup;
+    IntBufferType bufferType;
+    size_t deadElems;
+    int buffer;
+    Fixture(const Setup &setup_)
+        : setup(setup_),
+          bufferType(ARRAYS_SIZE, setup._minArrays, MAX_ARRAYS, NUM_ARRAYS_FOR_NEW_BUFFER, setup._allocGrowFactor),
+          deadElems(0),
+          buffer(0)
+    {}
+    ~Fixture() {
+        bufferType.onHold(&setup._usedElems);
+        bufferType.onFree(setup._usedElems);
+    }
+    void onActive() {
+        bufferType.onActive(setup._bufferId, &setup._usedElems, deadElems, &buffer);
+    }
+    size_t arraysToAlloc() {
+        return bufferType.calcArraysToAlloc(setup._bufferId, setup._neededElems, setup._resizing);
+    }
+};
+
+void
+assertArraysToAlloc(size_t exp, const Setup &setup)
+{
+    Fixture f(setup);
+    f.onActive();
+    EXPECT_EQUAL(exp, f.arraysToAlloc());
+}
+
+TEST("require that complete arrays are allocated")
+{
+    TEST_DO(assertArraysToAlloc(1, Setup().needed(1)));
+    TEST_DO(assertArraysToAlloc(1, Setup().needed(2)));
+    TEST_DO(assertArraysToAlloc(1, Setup().needed(3)));
+    TEST_DO(assertArraysToAlloc(1, Setup().needed(4)));
+    TEST_DO(assertArraysToAlloc(2, Setup().needed(5)));
+}
+
+TEST("require that reserved elements are taken into account when not resizing")
+{
+    TEST_DO(assertArraysToAlloc(2, Setup().needed(1).bufferId(0)));
+    TEST_DO(assertArraysToAlloc(2, Setup().needed(4).bufferId(0)));
+    TEST_DO(assertArraysToAlloc(3, Setup().needed(5).bufferId(0)));
+}
+
+TEST("require that arrays to alloc is based on currently used elements (no resizing)")
+{
+    TEST_DO(assertArraysToAlloc(2, Setup().used(4 * 4).needed(4)));
+    TEST_DO(assertArraysToAlloc(4, Setup().used(8 * 4).needed(4)));
+}
+
+TEST("require that arrays to alloc is based on currently used elements (with resizing)")
+{
+    TEST_DO(assertArraysToAlloc(4 + 2, Setup().used(4 * 4).needed(4).resizing(true)));
+    TEST_DO(assertArraysToAlloc(8 + 4, Setup().used(8 * 4).needed(4).resizing(true)));
+    TEST_DO(assertArraysToAlloc(4 + 3, Setup().used(4 * 4).needed(3 * 4).resizing(true)));
+}
+
+TEST("require that arrays to alloc always contain elements needed")
+{
+    TEST_DO(assertArraysToAlloc(2, Setup().used(4 * 4).needed(2 * 4)));
+    TEST_DO(assertArraysToAlloc(3, Setup().used(4 * 4).needed(3 * 4)));
+    TEST_DO(assertArraysToAlloc(4, Setup().used(4 * 4).needed(4 * 4)));
+}
+
+TEST("require that arrays to alloc is capped to max arrays")
+{
+    TEST_DO(assertArraysToAlloc(127, Setup().used(254 * 4).needed(4)));
+    TEST_DO(assertArraysToAlloc(128, Setup().used(256 * 4).needed(4)));
+    TEST_DO(assertArraysToAlloc(128, Setup().used(258 * 4).needed(8)));
+}
+
+TEST("require that arrays to alloc is capped to min arrays")
+{
+    TEST_DO(assertArraysToAlloc(16, Setup().used(30 * 4).needed(4).minArrays(16)));
+    TEST_DO(assertArraysToAlloc(16, Setup().used(32 * 4).needed(4).minArrays(16)));
+    TEST_DO(assertArraysToAlloc(17, Setup().used(34 * 4).needed(4).minArrays(16)));
+}
+
+TEST_MAIN() { TEST_RUN_ALL(); }