[jira] [Commented] (BEAM-9000) Java Test Assertions without toString for GenericJson subclasses

["Kirill Kozlov (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/BEAM-9000?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17003733#comment-17003733 ] 

Kirill Kozlov commented on BEAM-9000:
-------------------------------------

I believe that the following PR [1] is somewhat relevant to this, so I decided to link it here just in case.

 [1] [https://github.com/apache/beam/pull/10094]

CC: [~bhulette]

> Java Test Assertions without toString for GenericJson subclasses
> ----------------------------------------------------------------
>
>                 Key: BEAM-9000
>                 URL: https://issues.apache.org/jira/browse/BEAM-9000
>             Project: Beam
>          Issue Type: Improvement
>          Components: testing
>            Reporter: Tomo Suzuki
>            Assignee: Tomo Suzuki
>            Priority: Minor
>             Fix For: 2.19.0
>
>          Time Spent: 2h
>  Remaining Estimate: 0h
>
> As of now, there are many tests that assert on {{toString()}} of objects.
> {code:java}
>     CounterUpdate result = testObject.transform(monitoringInfo);
>     assertEquals(
>         "{cumulative=true, integer={highBits=0, lowBits=0}, "
>             + "nameAndKind={kind=SUM, "
>             + "name=transformedValue-ElementCount}}",
>         result.toString());
> {code}
> This style is prone to unnecessary maintenance of the test code when upgrading dependencies. Dependencies may change the internal ordering of fields and trivial change in {{toString()}}. In BEAM-8695, where I tried to upgrade google-http-client, there are ~30 comparison failure due to this {{toString}} assertions.
> They are subclasses of {{com.google.api.client.json.GenericJson}}. 
> Several options to enhance these assertions.
> h1. Option 1: Assertion using Map
> Leveraging the fact that GenericJson is a subclass of AbstractMap<String, Object>, the assertion can be written as
> {code:java}
>     ImmutableMap<String, Object> expected = ImmutableMap.of("cumulative", true,
>         "integer", ImmutableMap.of("highBits", 0, "lowBits", 0),
>         "nameAndKind", ImmutableMap.of("kind", "SUM", "name", "transformedValue-ElementCount"));
>     assertEquals(expected, (Map<String, Object>)result);
> {code}
> Credit: Ben Whitehead.
> h1. Option 2: Create assertEqualsOnJson
> Leveraging the fact that instance of GenericJson can be instantiated through JSON, the assertion can be written as
> {code:java}
>     assertEqualsOnJson(
>         "{\"cumulative\":true, \"integer\":{\"highBits\":0, \"lowBits\":0}, "
>             + "\"nameAndKind\":{\"kind\":\"SUM\", "
>             + "\"name\":\"transformedValue-ElementCount\"}}",
>         result);
> {code}
>  
> {{assertEqualsOnJson}} is implemented as below. The following field and methods should go to shared test utility class (sdks/testing?)
> {code:java}
>   private static final JacksonFactory jacksonFactory = JacksonFactory.getDefaultInstance();
>   public static <T extends GenericJson> void assertEqualsOnJson(String expectedJsonText, T actual) {
>     CounterUpdate expected = parse(expectedJsonText, CounterUpdate.class);
>     assertEquals(expected, actual);
>   }
>   public static <T extends GenericJson> T parse(String text, Class<T> clazz) {
>     try {
>       JsonParser parser = jacksonFactory.createJsonParser(text);
>       return parser.parse(clazz);
>     } catch (IOException ex) {
>       throw new IllegalArgumentException("Could not parse the text as " + clazz, ex);
>     }
>   }
> {code}
> A feature request to handle escaping double quotes via JacksonFactory: [https://github.com/googleapis/google-http-java-client/issues/923]
>  
> h1. Option3: Check JSON equality via JSONassert
> * https://github.com/skyscreamer/JSONassert
> * https://github.com/hertzsprung/hamcrest-json (Not using as last commit was in 2012) 
> The JSONassert example does not carry quoted double quote characters. The implementation would be converting actual object into JSON object and calling {{JSONAssert.assertEqual}}.
> Credit: Luke Cwik
>  



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