2 files changed, 127 insertions, 0 deletions
diff --git a/eval/src/tests/tensor/index_lookup_table/CMakeLists.txt b/eval/src/tests/tensor/index_lookup_table/CMakeLists.txt
new file mode 100644
index 00000000000..f2dc5d31045
--- /dev/null
+++ b/eval/src/tests/tensor/index_lookup_table/CMakeLists.txt
@@ -0,0 +1,9 @@
+# Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+vespa_add_executable(eval_index_lookup_table_test_app TEST
+    SOURCES
+    index_lookup_table_test.cpp
+    DEPENDS
+    vespaeval
+    gtest
+)
+vespa_add_test(NAME eval_index_lookup_table_test_app COMMAND eval_index_lookup_table_test_app)
diff --git a/eval/src/tests/tensor/index_lookup_table/index_lookup_table_test.cpp b/eval/src/tests/tensor/index_lookup_table/index_lookup_table_test.cpp
new file mode 100644
index 00000000000..3f806e8252c
--- /dev/null
+++ b/eval/src/tests/tensor/index_lookup_table/index_lookup_table_test.cpp
@@ -0,0 +1,118 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include <vespa/eval/tensor/dense/index_lookup_table.h>
+#include <vespa/eval/eval/function.h>
+#include <vespa/eval/eval/value_type.h>
+#include <vespa/vespalib/gtest/gtest.h>
+
+using namespace vespalib::eval;
+using namespace vespalib::tensor;
+
+std::vector<uint32_t> make_table(std::vector<uint32_t> list) { return list; }
+
+TEST(IndexLookupTableTest, single_dimension_lookup_table_is_correct)
+{
+    auto idx_fun = Function::parse({"x"}, "5-x");
+    auto type = ValueType::from_spec("tensor(x[6])");
+    auto table = IndexLookupTable::create(*idx_fun, type);
+
+    EXPECT_EQ(IndexLookupTable::num_cached(), 1);
+    EXPECT_EQ(IndexLookupTable::count_refs(), 1);
+    EXPECT_EQ(table->get(), make_table({5,4,3,2,1,0}));
+}
+
+TEST(IndexLookupTableTest, dual_dimension_lookup_table_is_correct)
+{
+    auto idx_fun = Function::parse({"x","y"}, "5-(x*2+y)");
+    auto type = ValueType::from_spec("tensor(x[3],y[2])");
+    auto table = IndexLookupTable::create(*idx_fun, type);
+
+    EXPECT_EQ(IndexLookupTable::num_cached(), 1);
+    EXPECT_EQ(IndexLookupTable::count_refs(), 1);
+    EXPECT_EQ(table->get(), make_table({5,4,3,2,1,0}));
+}
+
+TEST(IndexLookupTableTest, multi_dimension_lookup_table_is_correct)
+{
+    auto idx_fun = Function::parse({"a","b","c","d"}, "11-(a*6+b*2+c*2+d)");
+    auto type = ValueType::from_spec("tensor(a[2],b[3],c[1],d[2])");
+    auto table = IndexLookupTable::create(*idx_fun, type);
+
+    EXPECT_EQ(IndexLookupTable::num_cached(), 1);
+    EXPECT_EQ(IndexLookupTable::count_refs(), 1);
+    EXPECT_EQ(table->get(), make_table({11,10,9,8,7,6,5,4,3,2,1,0}));
+}
+
+TEST(IndexLookupTableTest, lookup_tables_can_be_shared)
+{
+    auto idx_fun1 = Function::parse({"x"}, "5-x");
+    auto type1 = ValueType::from_spec("tensor(x[6])");
+    auto table1 = IndexLookupTable::create(*idx_fun1, type1);
+
+    auto idx_fun2 = Function::parse({"x"}, "5-x");
+    auto type2 = ValueType::from_spec("tensor(x[6])");
+    auto table2 = IndexLookupTable::create(*idx_fun2, type2);
+
+    EXPECT_EQ(IndexLookupTable::num_cached(), 1);
+    EXPECT_EQ(IndexLookupTable::count_refs(), 2);
+    EXPECT_EQ(&table1->get(), &table2->get());
+    EXPECT_EQ(table1->get(), make_table({5,4,3,2,1,0}));
+}
+
+TEST(IndexLookupTableTest, lookup_tables_with_different_index_functions_are_not_shared)
+{
+    auto idx_fun1 = Function::parse({"x"}, "5-x");
+    auto type1 = ValueType::from_spec("tensor(x[6])");
+    auto table1 = IndexLookupTable::create(*idx_fun1, type1);
+
+    auto idx_fun2 = Function::parse({"x"}, "x");
+    auto type2 = ValueType::from_spec("tensor(x[6])");
+    auto table2 = IndexLookupTable::create(*idx_fun2, type2);
+
+    EXPECT_EQ(IndexLookupTable::num_cached(), 2);
+    EXPECT_EQ(IndexLookupTable::count_refs(), 2);
+    EXPECT_NE(&table1->get(), &table2->get());
+    EXPECT_EQ(table1->get(), make_table({5,4,3,2,1,0}));
+    EXPECT_EQ(table2->get(), make_table({0,1,2,3,4,5}));
+}
+
+TEST(IndexLookupTableTest, lookup_tables_with_different_value_types_are_not_shared)
+{
+    auto idx_fun1 = Function::parse({"x"}, "x");
+    auto type1 = ValueType::from_spec("tensor(x[6])");
+    auto table1 = IndexLookupTable::create(*idx_fun1, type1);
+
+    auto idx_fun2 = Function::parse({"x"}, "x");
+    auto type2 = ValueType::from_spec("tensor(x[5])");
+    auto table2 = IndexLookupTable::create(*idx_fun2, type2);
+
+    EXPECT_EQ(IndexLookupTable::num_cached(), 2);
+    EXPECT_EQ(IndexLookupTable::count_refs(), 2);
+    EXPECT_NE(&table1->get(), &table2->get());
+    EXPECT_EQ(table1->get(), make_table({0,1,2,3,4,5}));
+    EXPECT_EQ(table2->get(), make_table({0,1,2,3,4}));
+}
+
+TEST(IndexLookupTableTest, identical_lookup_tables_might_not_be_shared)
+{
+    auto idx_fun1 = Function::parse({"x"}, "5-x");
+    auto type1 = ValueType::from_spec("tensor(x[6])");
+    auto table1 = IndexLookupTable::create(*idx_fun1, type1);
+
+    auto idx_fun2 = Function::parse({"x","y"}, "5-(x*2+y)");
+    auto type2 = ValueType::from_spec("tensor(x[3],y[2])");
+    auto table2 = IndexLookupTable::create(*idx_fun2, type2);
+
+    EXPECT_EQ(IndexLookupTable::num_cached(), 2);
+    EXPECT_EQ(IndexLookupTable::count_refs(), 2);
+    EXPECT_NE(&table1->get(), &table2->get());
+    EXPECT_EQ(table1->get(), make_table({5,4,3,2,1,0}));
+    EXPECT_EQ(table2->get(), make_table({5,4,3,2,1,0}));
+}
+
+TEST(IndexLookupTableTest, unused_lookup_tables_are_discarded) {
+    EXPECT_EQ(IndexLookupTable::num_cached(), 0);
+    EXPECT_EQ(IndexLookupTable::count_refs(), 0);
+}
+
+GTEST_MAIN_RUN_ALL_TESTS()