[EmbedUrlProcessorServlet] Non-deterministic behavior of Class.getDeclaredFields() might fail test EmbedUrlProcessorServletTest.testUrlWithRegisteredProvider()

[SaaiVenkat]

Bug Report

Current Behavior

• EmbedUrlProcessorServlet.doGet() writes the result fetch into UrlProcessor.Result as JSON using ObjectMapper at https://github.com/adobe/aem-core-wcm-components/blob/3524e33424bf6831faca014284c5bad803d3744d/bundles/core/src/main/java/com/adobe/cq/wcm/core/components/internal/servlets/embed/EmbedUrlProcessorServlet.java#L69-L84
• However, ObjectMapper.writeValue() converts the value into JSON by fetching the fields of UrlProcessorResultImpl, which are processor and options, using Java reflection Class.getDeclaredFields() at AnnotatedFieldCollector.java:73
• The official Javadoc of Class.getDeclaredFields() mentions that the elements are not returned in any particular order. This causes issue where the order of class fields are expected to be in a specific order.
• Specifically, this assumption could be observed in com.adobe.cq.wcm.core.components.internal.servlets.embed.EmbedUrlProcessorServletTest.testUrlWithRegisteredProvider(), where the JSON string result from the EmbedUrlProcessorServlet.doGet() is expected to be in the order of process followed by options at https://github.com/adobe/aem-core-wcm-components/blob/3524e33424bf6831faca014284c5bad803d3744d/bundles/core/src/test/java/com/adobe/cq/wcm/core/components/internal/servlets/embed/EmbedUrlProcessorServletTest.java#L74
• But this order might be changed based on the order of fields returned by Class.getDeclaredFields(), which could result in the following error

  [INFO] Results:
  [INFO] 
  [ERROR] Failures: 
  [ERROR]   EmbedUrlProcessorServletTest.testUrlWithRegisteredProvider:78 Does not match the expected response output. ==> expected: <{"processor":"pinterest","options":{"pinId":"99360735500167749"}}> but was: <{"options":{"pinId":"99360735500167749"},"processor":"pinterest"}>
  [INFO] 
  [ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0
  [INFO] 

Steps to reproduce

• We could observe the above mentioned issue by running the test through NonDex, which shuffles the order of elements returned by Class.getDeclaredFields()

  
  # Clone the Repo
  https://github.com/adobe/aem-core-wcm-components.git

Compile the module byte-buddy-dep

mvn clean install -pl bundles/core -am -DskipTests

(Optional) Run the unit test

mvn -pl bundles/core test -Dtest=com.adobe.cq.wcm.core.components.internal.servlets.embed.EmbedUrlProcessorServletTest#testUrlWithRegisteredProvider

Run the unit test using NonDex

mvn -pl bundles/core edu.illinois:nondex-maven-plugin:2.1.1:nondex -Dtest=com.adobe.cq.wcm.core.components.internal.servlets.embed.EmbedUrlProcessorServletTest#testUrlWithRegisteredProvider

**Expected behavior/code**
- For any amount of runs, the test should have passes successfully (with `NonDex` too). 
- The expected order of elements might not necessarily be `processor` followed by `options`. 

**Environment**
- Core Components version: `2.23.5-SNAPSHOT`
- Java version: `Java(TM) SE Runtime Environment (build 1.8.0_381-b09)`

**Possible Solution 1**
- Since the test validates the data of the json and not the order, we can convert the strings to `JsonNode` and compare the nodes.

+/- com.adobe.cq.wcm.core.components.internal.servlets.embed.EmbedUrlProcessorServletTest.testUrlWithRegisteredProvider()

• String expectedOutput = "{\"processor\":\"pinterest\",\"options\":{\"pinId\":\"99360735500167749\"}}";

• assertEquals(expectedOutput, context.response().getOutputAsString(), "Does not match the expected response output.");

• ObjectMapper mapper = new ObjectMapper();

• JsonNode expected = mapper.readTree("{\"processor\":\"pinterest\",\"options\":{\"pinId\":\"99360735500167749\"}}");

• JsonNode actual = mapper.readTree(context.response().getOutputAsString());

• assertEquals(expected, actual, "Does not match the expected response output.");

  
  **Possible Solution 2**

• Since the order of elements might change inside ObjectMapper and there are only two possible strings returned, we could expect both the possibilities in the test.

  
  +/-  com.adobe.cq.wcm.core.components.internal.servlets.embed.EmbedUrlProcessorServletTest.testUrlWithRegisteredProvider()

• String expectedOutput = "{\"processor\":\"pinterest\",\"options\":{\"pinId\":\"99360735500167749\"}}";

• assertEquals(expectedOutput, context.response().getOutputAsString(), "Does not match the expected response output.");

• String expectedOutput1 = "{\"processor\":\"pinterest\",\"options\":{\"pinId\":\"99360735500167749\"}}";

• String expectedOutput2 = "{\"options\":{\"pinId\":\"99360735500167749\"},\"processor\":\"pinterest\"}";

• String actualOutput = context.response().getOutputAsString();

• assertTrue(expectedOutput1.equals(actualOutput) || expectedOutput2.equals(actualOutput), "Does not match the expected response output.");

• If the proposed solution looks good, I can create a PR.