Add opt-in rule balanced_xctest_lifecycle

CHANGELOG.md

@@ -48,9 +48,10 @@
   `assert(false)`.  
   [Otavio Cordeiro](https://github.com/otaviocc)
 
-* Add opt-in rule `private_subject` rule which warns against
-  public Combine subjects.  
+* Adds `balanced_xctest_lifecycle` opt-in rule to enforce balanced `setUp`
+  and `tearDown` methods in a test class.  
   [Otavio Cordeiro](https://github.com/otaviocc)
+  [#3452](https://github.com/realm/SwiftLint/issues/3452)
 
 * Tweak the auto-correction result console output for clarity.  
   [mokagio](https://github.com/mokagio)
@@ -91,6 +92,10 @@
   variable when running analyze.  
   [jpsim](https://github.com/jpsim)
 
+* Add opt-in rule `private_subject` rule which warns against
+  public Combine subjects.  
+  [Otavio Cordeiro](https://github.com/otaviocc)
+
 #### Bug Fixes
 
 * Fix `custom_rules` merging when the parent configuration is based on

Source/SwiftLintFramework/Models/PrimaryRuleList.swift

@@ -155,6 +155,7 @@ public let primaryRuleList = RuleList(rules: [
     RedundantVoidReturnRule.self,
     RequiredDeinitRule.self,
     RequiredEnumCaseRule.self,
+    BalancedXCTestLifecycleRule.self,
     ReturnArrowWhitespaceRule.self,
     ShorthandOperatorRule.self,
     SingleTestClassRule.self,

Source/SwiftLintFramework/Rules/Lint/BalancedXCTestLifecycleRule.swift

@@ -0,0 +1,159 @@
+import SourceKittenFramework
+
+public struct BalancedXCTestLifecycleRule: Rule, OptInRule, ConfigurationProviderRule, AutomaticTestableRule {
+    // MARK: - Properties
+
+    public var configuration = SeverityConfiguration(.warning)
+
+    public static let description = RuleDescription(
+        identifier: "balanced_xctest_lifecycle",
+        name: "Balanced XCTest life-cycle",
+        description: "Test classes must implement balanced setUp and tearDown methods.",
+        kind: .lint,
+        nonTriggeringExamples: [
+            Example(#"""
+            final class FooTests: XCTestCase {
+                override func setUp() {}
+                override func tearDown() {}
+            }
+            """#),
+            Example(#"""
+            final class FooTests: XCTestCase {
+                override func setUpWithError() throws {}
+                override func tearDown() {}
+            }
+            """#),
+            Example(#"""
+            final class FooTests: XCTestCase {
+                override func setUp() {}
+                override func tearDownWithError() throws {}
+            }
+            """#),
+            Example(#"""
+            final class FooTests: XCTestCase {
+                override func setUpWithError() throws {}
+                override func tearDownWithError() throws {}
+            }
+            final class BarTests: XCTestCase {
+                override func setUpWithError() throws {}
+                override func tearDownWithError() throws {}
+            }
+            """#),
+            Example(#"""
+            struct FooTests {
+                override func setUp() {}
+            }
+            class BarTests {
+                override func setUpWithError() throws {}
+            }
+            """#),
+            Example(#"""
+            final class FooTests: XCTestCase {
+                override func setUpAlLExamples() {}
+            }
+            """#),
+            Example(#"""
+            final class FooTests: XCTestCase {
+                class func setUp() {}
+                class func tearDown() {}
+            }
+            """#)
+        ],
+        triggeringExamples: [
+            Example(#"""
+            final class ↓FooTests: XCTestCase {
+                override func setUp() {}
+            }
+            """#),
+            Example(#"""
+            final class ↓FooTests: XCTestCase {
+                override func setUpWithError() throws {}
+            }
+            """#),
+            Example(#"""
+            final class FooTests: XCTestCase {
+                override func setUp() {}
+                override func tearDownWithError() throws {}
+            }
+            final class ↓BarTests: XCTestCase {
+                override func setUpWithError() throws {}
+            }
+            """#),
+            Example(#"""
+            final class ↓FooTests: XCTestCase {
+                class func tearDown() {}
+            }
+            """#),
+            Example(#"""
+            final class ↓FooTests: XCTestCase {
+                override func tearDown() {}
+            }
+            """#),
+            Example(#"""
+            final class ↓FooTests: XCTestCase {
+                override func tearDownWithError() throws {}
+            }
+            """#),
+            Example(#"""
+            final class FooTests: XCTestCase {
+                override func setUp() {}
+                override func tearDownWithError() throws {}
+            }
+            final class ↓BarTests: XCTestCase {
+                override func tearDownWithError() throws {}
+            }
+            """#)
+        ]
+    )
+
+    // MARK: - Life cycle
+
+    public init() {}
+
+    // MARK: - Public
+
+    public func validate(file: SwiftLintFile) -> [StyleViolation] {
+        testClasses(in: file).compactMap { violations(in: file, for: $0) }
+    }
+
+    // MARK: - Private
+
+    private func testClasses(in file: SwiftLintFile) -> [SourceKittenDictionary] {
+        file.structureDictionary.substructure.filter { dictionary in
+            guard dictionary.declarationKind == .class else { return false }
+            return dictionary.inheritedTypes.contains("XCTestCase")
+        }
+    }
+
+    private func violations(in file: SwiftLintFile,
+                            for dictionary: SourceKittenDictionary) -> StyleViolation? {
+        let methods = dictionary.substructure
+            .compactMap { XCTMethod($0.name) }
+
+        guard
+            methods.contains(.setUp) != methods.contains(.tearDown),
+            let offset = dictionary.nameOffset
+        else {
+            return nil
+        }
+
+        return StyleViolation(ruleDescription: Self.description,
+                              severity: configuration.severity,
+                              location: Location(file: file, byteOffset: offset))
+    }
+}
+
+// MARK: - Private
+
+private enum XCTMethod {
+    case setUp
+    case tearDown
+
+    init?(_ name: String?) {
+        switch name {
+        case "setUp()", "setUpWithError()": self = .setUp
+        case "tearDown()", "tearDownWithError()": self = .tearDown
+        default: return nil
+        }
+    }
+}

Tests/LinuxMain.swift

@@ -1,6 +1,5 @@
-// Generated using Sourcery 1.0.2 — https://github.com/krzysztofzablocki/Sourcery
+// Generated using Sourcery 1.2.0 — https://github.com/krzysztofzablocki/Sourcery
 // DO NOT EDIT
-
 @testable import SwiftLintFrameworkTests
 import XCTest
 
@@ -34,6 +33,12 @@ extension AttributesRuleTests {
     ]
 }
 
+extension BalancedXCTestLifecycleRuleTests {
+    static var allTests: [(String, (BalancedXCTestLifecycleRuleTests) -> () throws -> Void)] = [
+        ("testWithDefaultConfiguration", testWithDefaultConfiguration)
+    ]
+}
+
 extension BlockBasedKVORuleTests {
     static var allTests: [(String, (BlockBasedKVORuleTests) -> () throws -> Void)] = [
         ("testWithDefaultConfiguration", testWithDefaultConfiguration)
@@ -185,12 +190,15 @@ extension ConfigurationTests {
         ("testInitWithRelativePathAndRootPath", testInitWithRelativePathAndRootPath),
         ("testEnableAllRulesConfiguration", testEnableAllRulesConfiguration),
         ("testOnlyRules", testOnlyRules),
+        ("testOnlyRulesWithCustomRules", testOnlyRulesWithCustomRules),
         ("testWarningThreshold_value", testWarningThreshold_value),
         ("testWarningThreshold_nil", testWarningThreshold_nil),
         ("testOtherRuleConfigurationsAlongsideOnlyRules", testOtherRuleConfigurationsAlongsideOnlyRules),
         ("testDisabledRules", testDisabledRules),
         ("testDisabledRulesWithUnknownRule", testDisabledRulesWithUnknownRule),
         ("testDuplicatedRules", testDuplicatedRules),
+        ("testIncludedExcludedRelativeLocationLevel1", testIncludedExcludedRelativeLocationLevel1),
+        ("testIncludedExcludedRelativeLocationLevel0", testIncludedExcludedRelativeLocationLevel0),
         ("testExcludedPaths", testExcludedPaths),
         ("testForceExcludesFile", testForceExcludesFile),
         ("testForceExcludesFileNotPresentInExcluded", testForceExcludesFileNotPresentInExcluded),
@@ -220,6 +228,9 @@ extension ConfigurationTests {
         ("testOnlyRulesMerging", testOnlyRulesMerging),
         ("testCustomRulesMerging", testCustomRulesMerging),
         ("testMergingAllowsDisablingParentsCustomRules", testMergingAllowsDisablingParentsCustomRules),
+        ("testCustomRulesMergingWithOnlyRulesCase1", testCustomRulesMergingWithOnlyRulesCase1),
+        ("testCustomRulesMergingWithOnlyRulesCase2", testCustomRulesMergingWithOnlyRulesCase2),
+        ("testCustomRulesReconfiguration", testCustomRulesReconfiguration),
         ("testLevel0", testLevel0),
         ("testLevel1", testLevel1),
         ("testLevel2", testLevel2),
@@ -1785,6 +1796,7 @@ XCTMain([
     testCase(AnyObjectProtocolRuleTests.allTests),
     testCase(ArrayInitRuleTests.allTests),
     testCase(AttributesRuleTests.allTests),
+    testCase(BalancedXCTestLifecycleRuleTests.allTests),
     testCase(BlockBasedKVORuleTests.allTests),
     testCase(ClassDelegateProtocolRuleTests.allTests),
     testCase(ClosingBraceRuleTests.allTests),

Tests/SwiftLintFrameworkTests/AutomaticRuleTests.generated.swift

@@ -1,6 +1,5 @@
-// Generated using Sourcery 1.0.2 — https://github.com/krzysztofzablocki/Sourcery
+// Generated using Sourcery 1.2.0 — https://github.com/krzysztofzablocki/Sourcery
 // DO NOT EDIT
-
 import SwiftLintFramework
 import XCTest
 
@@ -18,6 +17,12 @@ class ArrayInitRuleTests: XCTestCase {
     }
 }
 
+class BalancedXCTestLifecycleRuleTests: XCTestCase {
+    func testWithDefaultConfiguration() {
+        verifyRule(BalancedXCTestLifecycleRule.description)
+    }
+}
+
 class BlockBasedKVORuleTests: XCTestCase {
     func testWithDefaultConfiguration() {
         verifyRule(BlockBasedKVORule.description)