Move attribute lookup to separate extension

Author: hamtiko

Sources/SwiftFormat/CMakeLists.txt

@@ -42,6 +42,7 @@ add_library(SwiftFormat
   Core/SyntaxLintRule.swift
   Core/SyntaxProtocol+Convenience.swift
   Core/Trivia+Convenience.swift
+  Core/WithAttributesSyntax+Convenience.swift
   Core/WithSemicolonSyntax.swift
   PrettyPrint/Comment.swift
   PrettyPrint/Indent+Length.swift

Sources/SwiftFormat/Core/WithAttributesSyntax+Convenience.swift

@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SwiftSyntax
+
+extension WithAttributesSyntax {
+    /// Indicates whether the node has attribute with the given `name`.
+    ///
+    /// - Parameter name: The name of the attribute to lookup.
+    /// - Returns: True if the node has an attribute with the given `name`, otherwise false.
+    func hasAttribute(_ name: String) -> Bool {
+        attributes.contains { attribute in
+            let attributeName = attribute.as(AttributeSyntax.self)?.attributeName
+            return attributeName?.as(IdentifierTypeSyntax.self)?.name.text == name
+            // support @Module.Attribute syntax as well
+            || attributeName?.as(MemberTypeSyntax.self)?.name.text == name
+        }
+    }
+}

Sources/SwiftFormat/Rules/AlwaysUseLowerCamelCase.swift

@@ -100,10 +100,7 @@ public final class AlwaysUseLowerCamelCase: SyntaxLintRule {
 
     // We allow underscores in test names, because there's an existing convention of using
     // underscores to separate phrases in very detailed test names.
-    let allowUnderscores = testCaseFuncs.contains(node) || node.attributes.contains {
-      // Allow underscore for test functions with the `@Test` attribute.
-      $0.as(AttributeSyntax.self)?.attributeName.as(IdentifierTypeSyntax.self)?.name.text == "Test"
-    }
+    let allowUnderscores = testCaseFuncs.contains(node) || node.hasAttribute("Test")
 
     diagnoseLowerCamelCaseViolations(
       node.name, allowUnderscores: allowUnderscores,

Tests/SwiftFormatTests/Rules/AlwaysUseLowerCamelCaseTests.swift

@@ -217,7 +217,7 @@ final class AlwaysUseLowerCamelCaseTests: LintOrFormatRuleTestCase {
       """
       @Test
       func function_With_Test_Attribute() {}
-      @Test("Description for test functions",
+      @Testing.Test("Description for test functions",
             .tags(.testTag))
       func function_With_Test_Attribute_And_Args() {}
       func 1️⃣function_Without_Test_Attribute() {}