Set correct minimum OS targets for new packages using swift-testing (#7333)

Author: grynspan

Sources/Workspace/InitPackage.swift

@@ -186,8 +186,8 @@ public final class InitPackage {
 
             var platforms = options.platforms
 
-            // Macros require macOS 10.15, iOS 13, etc.
-            if packageType == .macro {
+            // Macros and swift-testing require macOS 10.15, iOS 13, etc.
+            if packageType == .macro || options.supportedTestingLibraries.contains(.swiftTesting) {
                 func addIfMissing(_ newPlatform: SupportedPlatform) {
                   if platforms.contains(where: { platform in
                       platform.platform == newPlatform.platform

Tests/WorkspaceTests/InitTests.swift

@@ -170,6 +170,11 @@ class InitTests: XCTestCase {
             let manifest = path.appending("Package.swift")
             XCTAssertFileExists(manifest)
             let manifestContents: String = try localFileSystem.readFileContents(manifest)
+            XCTAssertMatch(manifestContents, .contains(#".macOS(.v10_15)"#))
+            XCTAssertMatch(manifestContents, .contains(#".iOS(.v13)"#))
+            XCTAssertMatch(manifestContents, .contains(#".tvOS(.v13)"#))
+            XCTAssertMatch(manifestContents, .contains(#".watchOS(.v6)"#))
+            XCTAssertMatch(manifestContents, .contains(#".macCatalyst(.v13)"#))
             XCTAssertMatch(manifestContents, .contains(#"swift-testing.git", from: "0.2.0""#))
             XCTAssertMatch(manifestContents, .contains(#".product(name: "Testing", package: "swift-testing")"#))
 
@@ -208,6 +213,11 @@ class InitTests: XCTestCase {
             let manifest = path.appending("Package.swift")
             XCTAssertFileExists(manifest)
             let manifestContents: String = try localFileSystem.readFileContents(manifest)
+            XCTAssertMatch(manifestContents, .contains(#".macOS(.v10_15)"#))
+            XCTAssertMatch(manifestContents, .contains(#".iOS(.v13)"#))
+            XCTAssertMatch(manifestContents, .contains(#".tvOS(.v13)"#))
+            XCTAssertMatch(manifestContents, .contains(#".watchOS(.v6)"#))
+            XCTAssertMatch(manifestContents, .contains(#".macCatalyst(.v13)"#))
             XCTAssertMatch(manifestContents, .contains(#"swift-testing.git", from: "0.2.0""#))
             XCTAssertMatch(manifestContents, .contains(#".product(name: "Testing", package: "swift-testing")"#))