Extend assertMacroExpansion with an optional build configuration

Author: DougGregor

Package.swift

@@ -328,6 +328,7 @@ let package = Package(
         "_SwiftSyntaxGenericTestSupport",
         "SwiftDiagnostics",
         "SwiftIDEUtils",
+        "SwiftIfConfig",
         "SwiftParser",
         "SwiftSyntaxMacros",
         "SwiftSyntaxMacroExpansion",

Sources/SwiftSyntaxMacrosGenericTestSupport/Assertions.swift

@@ -13,6 +13,7 @@
 #if compiler(>=6)
 import SwiftBasicFormat
 public import SwiftDiagnostics
+public import SwiftIfConfig
 @_spi(FixItApplier) import SwiftIDEUtils
 import SwiftParser
 import SwiftParserDiagnostics
@@ -24,6 +25,7 @@ private import _SwiftSyntaxGenericTestSupport
 import SwiftBasicFormat
 import SwiftDiagnostics
 @_spi(FixItApplier) import SwiftIDEUtils
+import SwiftIfConfig
 import SwiftParser
 import SwiftParserDiagnostics
 import SwiftSyntax
@@ -497,6 +499,7 @@ public func assertMacroExpansion(
   testModuleName: String = "TestModule",
   testFileName: String = "test.swift",
   indentationWidth: Trivia = .spaces(4),
+  buildConfiguration: (any BuildConfiguration)? = nil,
   failureHandler: (TestFailureSpec) -> Void,
   fileID: StaticString = #fileID,
   filePath: StaticString = #filePath,
@@ -509,7 +512,8 @@ public func assertMacroExpansion(
 
   // Expand all macros in the source.
   let context = BasicMacroExpansionContext(
-    sourceFiles: [origSourceFile: .init(moduleName: testModuleName, fullFilePath: testFileName)]
+    sourceFiles: [origSourceFile: .init(moduleName: testModuleName, fullFilePath: testFileName)],
+    buildConfiguration: buildConfiguration
   )
 
   func contextGenerator(_ syntax: Syntax) -> BasicMacroExpansionContext {

Sources/SwiftSyntaxMacrosTestSupport/Assertions.swift

@@ -11,12 +11,14 @@
 //===----------------------------------------------------------------------===//
 
 #if compiler(>=6)
+public import SwiftIfConfig
 public import SwiftSyntax
 public import SwiftSyntaxMacroExpansion
 public import SwiftSyntaxMacros
 @_spi(XCTestFailureLocation) public import SwiftSyntaxMacrosGenericTestSupport
 private import XCTest
 #else
+import SwiftIfConfig
 import SwiftSyntax
 import SwiftSyntaxMacroExpansion
 import SwiftSyntaxMacros
@@ -57,6 +59,7 @@ public func assertMacroExpansion(
   testModuleName: String = "TestModule",
   testFileName: String = "test.swift",
   indentationWidth: Trivia = .spaces(4),
+  buildConfiguration: (any BuildConfiguration)? = nil,
   file: StaticString = #filePath,
   line: UInt = #line
 ) {
@@ -71,6 +74,7 @@ public func assertMacroExpansion(
     testModuleName: testModuleName,
     testFileName: testFileName,
     indentationWidth: indentationWidth,
+    buildConfiguration: buildConfiguration,
     file: file,
     line: line
   )
@@ -104,6 +108,7 @@ public func assertMacroExpansion(
   testModuleName: String = "TestModule",
   testFileName: String = "test.swift",
   indentationWidth: Trivia = .spaces(4),
+  buildConfiguration: (any BuildConfiguration)? = nil,
   file: StaticString = #filePath,
   line: UInt = #line
 ) {
@@ -117,6 +122,7 @@ public func assertMacroExpansion(
     testModuleName: testModuleName,
     testFileName: testFileName,
     indentationWidth: indentationWidth,
+    buildConfiguration: buildConfiguration,
     failureHandler: {
       XCTFail($0.message, file: $0.location.staticFilePath, line: $0.location.unsignedLine)
     },