Create rule S8037: Test classes should have only one @testSetup method

rules/S8037/apex/metadata.json

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+{
+  "title": "Test classes should have only one @testSetup method",
+  "type": "BUG",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant/Issue",
+    "constantCost": "5 min"
+  },
+  "tags": [
+    "apex",
+    "test"
+  ],
+  "defaultSeverity": "Blocker",
+  "ruleSpecification": "RSPEC-8037",
+  "sqKey": "S8037",
+  "scope": "Tests",
+  "defaultQualityProfiles": [
+    "Sonar way"
+  ],
+  "quickfix": "unknown",
+  "code": {
+    "impacts": {
+      "RELIABILITY": "BLOCKER",
+      "MAINTAINABILITY": "BLOCKER"
+    },
+    "attribute": "LOGICAL"
+  }
+}

rules/S8037/apex/rule.adoc

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+This is an issue when a test class contains multiple methods annotated with `@testSetup`.
+
+== Why is this an issue?
+
+In Apex, test classes can only contain one `@testSetup` method. The `@testSetup` annotation is used to create test data that will be available to all test methods in the class, improving test performance by avoiding duplicate data creation.
+
+When you define multiple `@testSetup` methods in the same test class, the Apex compiler will reject the code and throw a compilation error. This happens because the Salesforce platform expects exactly one setup method per test class to maintain predictable test execution order and data consistency.
+
+The `@testSetup` method runs once before all test methods in the class, creating a clean, consistent data state. Having multiple setup methods would create ambiguity about execution order and could lead to unpredictable test behavior.
+
+=== What is the potential impact?
+
+Multiple `@testSetup` methods will cause compilation errors, preventing the test class from being deployed or executed. This blocks development progress and can prevent deployments to production environments.
+
+== How to fix it
+
+Consolidate all setup logic into a single @testSetup method. Move the code from multiple setup methods into one method and remove the duplicate @testSetup annotations.
+
+=== Code examples
+
+==== Noncompliant code example
+
+[source,apex,diff-id=1,diff-type=noncompliant]
+----
+@isTest
+public class MyTestClass {
+    @testSetup
+    static void setup1() {
+        // setup code
+        Account acc = new Account(Name = 'Test Account');
+        insert acc;
+    }
+
+    @testSetup // Noncompliant
+    static void setup2() {
+        // more setup code
+        Contact con = new Contact(LastName = 'Test Contact');
+        insert con;
+    }
+}
+----
+
+==== Compliant solution
+
+[source,apex,diff-id=1,diff-type=compliant]
+----
+@isTest
+public class MyTestClass {
+    @testSetup
+    static void setup() {
+        // all setup code in one method
+        Account acc = new Account(Name = 'Test Account');
+        insert acc;
+
+        Contact con = new Contact(LastName = 'Test Contact');
+        insert con;
+    }
+}
+----
+
+== Resources
+
+=== Documentation
+
+ * Apex Testing Framework - https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_testing_framework.htm[Official Salesforce documentation on Apex testing framework and @testSetup usage]
+
+ * Unit Testing in Apex - https://www.apexhours.com/unit-testing-in-apex[Comprehensive guide on Apex unit testing including @testSetup best practices]
+
+=== Related rules
+
+ * RSPEC-3411 - https://rules.sonarsource.com/csharp/RSPEC-3411/[Similar rule for C# test classes with multiple setup methods]

rules/S8037/metadata.json

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+{
+}