Fixed flaky tests in CompatParquetReaderTest.java with ObjectMapper

[CaseyPan]

Description

Fixed flaky tests in CompatParquetReaderTest.java with ObjectMapper

druid/extensions-core/parquet-extensions/src/test/java/org/apache/druid/data/input/parquet/CompatParquetReaderTest.java

Line 43 in ad32f84

public class CompatParquetReaderTest extends BaseParquetReaderTest

Test: testBinaryAsString, testParquetThriftCompat, testReadNestedArrayStruct, testProtoStructWithArray

Steps to Reproduce:

1. Clone the repo

   git clone git clone https://github.com/apache/druid.git
   

2. Install the package

   mvn install -pl extensions-core/parquet-extensions -am -DskipTests
   

3. Run the test in regular runs

   mvn -pl extensions-core/parquet-extensions test -Dtest=org.apache.druid.data.input.parquet.CompatParquetReaderTest#testname
   

4. The test failed by running the test with Non-Dex tool.

   mvn -pl extensions-core/parquet-extensions edu.illinois:nondex-maven-plugin:2.1.1:nondex -Dcheckstyle.skip -Dtest=org.apache.druid.data.input.parquet.CompatParquetReaderTest#testname
   

The following is an example error message from testReadNestedArrayStruct

[ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 2.732 s <<< FAILURE! -- in org.apache.druid.data.input.parquet.CompatParquetReaderTest
[ERROR] org.apache.druid.data.input.parquet.CompatParquetReaderTest.testReadNestedArrayStruct -- Time elapsed: 0.052 s <<< FAILURE!
org.junit.ComparisonFailure: 
expected:<{
  "[primitive" : 2,
  "myComplex" : [ {
    "id" : 1,
    "repeatedMessage" : [ 3 ]
  } ]]
}> but was:<{
  "[myComplex" : [ {
    "id" : 1,
    "repeatedMessage" : [ 3 ]
  } ],
  "primitive" : 2]
}>
        at org.junit.Assert.assertEquals(Assert.java:117)
        at org.junit.Assert.assertEquals(Assert.java:146)
        at org.apache.druid.data.input.parquet.CompatParquetReaderTest.testReadNestedArrayStruct(CompatParquetReaderTest.java:392)

Reason of flakiness:
These tests check the equality of two JSON strings. The data reading methods used createReader() in those tests do not retrieve data in a consistent order, which can possibly lead to different JSON representations of the same data during test runs.

Changes:

• Imported fasterxml.jackson package, and changed from using standard assertion method Assert to using JSONNode and ObjectMapper, which parse two JSON strings and convert them to a tree structure and each node in the trees are compared. Thus, the order of the elements in JSON strings is deterministic and the test passes.

Release note

Fixed: CompatParquetReaderTest tests no longer fail when running with the NonDex tool.

---

This PR has:

• been self-reviewed.
• added documentation for new or modified features or behaviors.
• a release note entry in the PR description.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.

[zzjas]

Have you checked if any existing dependency has the ability to compare JSON strings? I saw com.fasterxml.jackson in the pom file and you might want to check that.

[prathyushreddylpr]

What is the reason for adding try-catch blocks? I see that you are any way throwing RuntimeException in catch block, what is the use of changing the type of exception