SONARJAVA-5410 Update rules metadata for S5977 (#5098)

Author: tomasz-tylenda-sonarsource

sonar-java-plugin/src/main/resources/org/sonar/l10n/java/rules/java/S5977.html

@@ -1,30 +1,40 @@
 <h2>Why is this an issue?</h2>
-<p>Tests should always:</p>
+<p>Randomness in test code, whether introduced intentionally to cover multiple scenarios or unintentionally through non-deterministic library
+functions, undermines the principles of effective testing. In most cases, randomness leads to problems, resulting in code that is unreliable and
+difficult to debug. Consequently, deterministic and reproducible tests are preferred, primarily for the following reasons:</p>
 <ul>
-  <li> Make sure that production code behaves as expected, including edge cases. </li>
-  <li> Be easy to debug, i.e. understandable and reproducible. </li>
+  <li> When a test fails, the ability to reproduce the conditions that led to the failure is crucial for effective debugging. Randomness can make it
+  difficult or even impossible to pinpoint the root cause, as subsequent runs may not exhibit the same failure. </li>
+  <li> Being able to replay a scenario allows us to easily compare logs between different test runs. </li>
+  <li> Determinism gives us confidence that a bug is fixed when it no longer appears in tests. If they behave randomly, a passing test after a fix
+  might be coincidental due to a specific random input, rather than a genuine resolution of the underlying problem. </li>
+  <li> Flaky tests, which pass or fail intermittently without any code changes, are a significant problem for CI pipelines (continuous integration).
+  They erode confidence in the CI system, lead to unnecessary investigations and reruns, and ultimately slow down the development and release process.
+  A stable CI pipeline relies on deterministic test outcomes. </li>
 </ul>
-<p>Using random values in tests will not necessarily check edge cases, and it will make test logs a lot harder to read. It is better to use easily
-readable hardcoded values. If this makes your code bigger you can use helper functions.</p>
-<p>There is one valid use case for random data in tests: when testing every value would make tests impractically slow. In this case the best you can
-do is use random to test every value on the long run. You should however make sure that random values are logged so that you can reproduce failures.
-Some libraries exist to make all this easier. You can for example use property-based testing libraries such as <a
-href="https://github.com/jlink/jqwik">jqwik</a>.</p>
 <p>This rule raises an issue when <code>new Random()</code> or <code>UUID.randomUUID()</code> are called in test code.</p>
+<h2>How to fix it</h2>
+<ul>
+  <li> When a test uses random numbers to generate inputs, an easy fix is to replace those random inputs with pseudo-random values generated from a
+  known seed. By initializing a pseudo-random number generator with a fixed seed, tests can generate sequences of seemingly random data that are
+  reproducible across different test runs. </li>
+  <li> When randomness occurs due to the use of a library function, the solution is to replace the call with a constant. For example, rather than
+  generating a UUID at random, one should use a fixed value. </li>
+</ul>
 <h3>Noncompliant code example</h3>
 <pre>
 int userAge = new Random().nextInt(42);  // Noncompliant
 UUID userID = UUID.randomUUID(); // Noncompliant
 </pre>
 <h3>Compliant solution</h3>
 <pre>
-int userAge = 31;
+static final int SEED = 0x533d;
+int userAge = new Random(SEED).nextInt(42);
 UUID userID = UUID.fromString("00000000-000-0000-0000-000000000001");
 </pre>
 <h2>Resources</h2>
 <ul>
   <li> <a href="https://phauer.com/2019/modern-best-practices-testing-java/#use-fixed-data-instead-of-randomized-data">Modern Best Practices for
   Testing in Java - Philipp Hauer</a> </li>
-  <li> <a href="https://jqwik.net/">Jqwik test engine</a> </li>
 </ul>
 

sonarpedia.json

@@ -3,7 +3,7 @@
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