Add unit test

cpp/src/parquet/schema-test.cc

@@ -566,6 +566,16 @@ TEST(TestColumnDescriptor, TestAttrs) {
   ASSERT_EQ(Type::BYTE_ARRAY, descr.physical_type());
 
   ASSERT_EQ(-1, descr.type_length());
+  ASSERT_EQ(
+      R"(column descriptor = {
+  name: name
+  path: 
+  physical_type: BYTE_ARRAY
+  logical_type: UTF8
+  max_definition_level: 4
+  max_repetition_level: 1
+})",
+      descr.ToString());
 
   // Test FIXED_LEN_BYTE_ARRAY
   node = PrimitiveNode::Make("name", Repetition::OPTIONAL, Type::FIXED_LEN_BYTE_ARRAY,
@@ -574,6 +584,20 @@ TEST(TestColumnDescriptor, TestAttrs) {
 
   ASSERT_EQ(Type::FIXED_LEN_BYTE_ARRAY, descr.physical_type());
   ASSERT_EQ(12, descr.type_length());
+
+  ASSERT_EQ(
+      R"(column descriptor = {
+  name: name
+  path: 
+  physical_type: FIXED_LEN_BYTE_ARRAY
+  logical_type: DECIMAL
+  max_definition_level: 4
+  max_repetition_level: 1
+  length: 12
+  precision: 10
+  scale: 4
+})",
+      descr.ToString());
 }
 
 class TestSchemaDescriptor : public ::testing::Test {