string compression tests

test/CMakeLists.txt

@@ -76,6 +76,7 @@ set(CORE_TEST_SOURCES
     test_shared.cpp
     test_status.cpp
     test_string_data.cpp
+    test_string_compression.cpp
     test_table_view.cpp
     test_thread.cpp
     test_transactions.cpp

test/test_string_compression.cpp

@@ -0,0 +1,61 @@
+/*************************************************************************
+ *
+ * Copyright 2024 Realm Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ **************************************************************************/
+
+#include "testsettings.hpp"
+
+#include <cstring>
+#include <string>
+#include <sstream>
+
+#include <realm.hpp>
+#include <realm/string_data.hpp>
+#include <realm/unicode.hpp>
+#include <realm/string_interner.hpp>
+
+#include "test.hpp"
+
+using namespace realm;
+
+
+ONLY(StringInterner_Basic_Creation)
+{
+    Group group;
+    TableRef table = group.add_table("test");
+    auto string_col_key = table->add_column(type_String, "string");
+    auto obj = table->create_object();
+    std::string my_string = "aaaaaaaaaaaaaaa";
+    obj.set(string_col_key, StringData(my_string));
+
+    Array dummy_parent{obj.get_alloc()};
+    dummy_parent.create(realm::NodeHeader::type_HasRefs);
+    dummy_parent.add(0);
+    StringInterner string_interner(obj.get_alloc(), dummy_parent, string_col_key, true);
+    auto id = string_interner.intern(obj.get_any(string_col_key).get_string());
+
+    const auto stored_id = string_interner.lookup(StringData(my_string));
+    CHECK(stored_id);
+    CHECK(*stored_id == id);
+
+    // this fails ... the id retured is 1 but the size of the compressed strings is 1.
+    // either the stored id should be 0 or we should start indexing from 1.
+    CHECK(string_interner.compare(StringData(my_string), *stored_id) == 0); // should be equal
+    const auto origin_string = string_interner.get(id);
+    CHECK(obj.get_any(string_col_key).get_string() == origin_string);
+
+    CHECK(string_interner.compare(*stored_id, id) == 0); // compare agaist self.
+}