GH-35460: Add ObjectParser unit tests

Author: Reranko05

cpp/src/arrow/json/CMakeLists.txt

@@ -23,6 +23,7 @@ add_arrow_test(test
                from_string_test.cc
                parser_test.cc
                reader_test.cc
+               object_parser_test.cc
                PREFIX
                "arrow-json"
                EXTRA_LINK_LIBS

cpp/src/arrow/json/object_parser_test.cc

@@ -0,0 +1,115 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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 "arrow/json/object_parser.h"
+
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>
+
+#include <string>
+#include <unordered_map>
+
+#include "arrow/testing/gtest_util.h"
+
+namespace arrow {
+namespace json {
+namespace internal {
+
+TEST(ObjectParser, GetString) {
+  ObjectParser parser;
+
+  ASSERT_OK(parser.Parse(R"({"name":"arrow"})"));
+
+  ASSERT_OK_AND_ASSIGN(auto value, parser.GetString("name"));
+  EXPECT_EQ(value, "arrow");
+}
+
+TEST(ObjectParser, GetBool) {
+  ObjectParser parser;
+
+  ASSERT_OK(parser.Parse(R"({"enabled":true})"));
+
+  ASSERT_OK_AND_ASSIGN(auto value, parser.GetBool("enabled"));
+  EXPECT_TRUE(value);
+}
+
+TEST(ObjectParser, InvalidJson) {
+  ObjectParser parser;
+
+  EXPECT_RAISES_WITH_MESSAGE_THAT(
+      Invalid,
+      ::testing::HasSubstr("Json parse error"),
+      parser.Parse(R"({"name":)"));
+}
+
+TEST(ObjectParser, GetStringMap) {
+  ObjectParser parser;
+
+  ASSERT_OK(parser.Parse(R"({
+    "k1": "v1",
+    "k2": "v2"
+  })"));
+
+  ASSERT_OK_AND_ASSIGN(auto map, parser.GetStringMap());
+
+  ASSERT_EQ(map.size(), 2U);
+  EXPECT_EQ(map["k1"], "v1");
+  EXPECT_EQ(map["k2"], "v2");
+}
+
+TEST(ObjectParser, MissingKey) {
+  ObjectParser parser;
+
+  ASSERT_OK(parser.Parse(R"({
+    "name": "arrow"
+  })"));
+
+  ASSERT_RAISES(KeyError, parser.GetString("missing"));
+  ASSERT_RAISES(KeyError, parser.GetBool("missing"));
+}
+
+TEST(ObjectParser, WrongType) {
+  ObjectParser parser;
+
+  ASSERT_OK(parser.Parse(R"({
+    "flag": true,
+    "name": "arrow"
+  })"));
+
+  ASSERT_RAISES(TypeError, parser.GetString("flag"));
+  ASSERT_RAISES(TypeError, parser.GetBool("name"));
+}
+
+TEST(ObjectParser, NonObjectRoot) {
+  ObjectParser parser;
+
+  ASSERT_RAISES(TypeError, parser.Parse(R"(["a", "b"])"));
+}
+
+TEST(ObjectParser, EmptyObject) {
+  ObjectParser parser;
+
+  ASSERT_OK(parser.Parse(R"({})"));
+
+  ASSERT_OK_AND_ASSIGN(auto map, parser.GetStringMap());
+
+  EXPECT_TRUE(map.empty());
+}
+
+}  // namespace internal
+}  // namespace json
+}  // namespace arrow