[XcodeprojTests] Override SWIFT_LIBRARY_PATH in tests

This will keep the compiler and Swift library consistent during the tests. - <rdar://problem/34791474> Use the built Swift standard library in the generated Xcode project tests

Author: aciidgh

Tests/XcodeprojTests/FunctionalTests.swift

@@ -32,7 +32,7 @@ class FunctionalTests: XCTestCase {
  }
 
  func testSwiftExecWithCDep() {
-#if false
+#if os(macOS)
  fixture(name: "ClangModules/SwiftCMixed") { prefix in
  // This will also test Modulemap generation for xcodeproj.
  XCTAssertXcodeprojGen(prefix)
@@ -51,7 +51,7 @@ class FunctionalTests: XCTestCase {
  }
 
  func testXcodeProjWithPkgConfig() {
-#if false
+#if os(macOS)
  fixture(name: "Miscellaneous/PkgConfig") { prefix in
  let systemModule = prefix.appending(component: "SystemModule")
  // Create a shared library.
@@ -101,7 +101,7 @@ class FunctionalTests: XCTestCase {
  }
 
  func testSystemModule() {
-#if false
+#if os(macOS)
  // Because there isn't any one system target that we can depend on for testing purposes, we build our own.
  try! write(path: AbsolutePath("/tmp/fake.h")) { stream in
  stream <<< "extern const char GetFakeString(void);\n"
@@ -147,10 +147,19 @@ func XCTAssertXcodeBuild(project: AbsolutePath, file: StaticString = #file, line
  env["TOOLCHAINS"] = "default"
  }
  let xcconfig = project.appending(component: "overrides.xcconfig")
- let swiftCompilerPath = Resources.default.swiftCompiler.asString
- try localFileSystem.writeFileContents(xcconfig) {
- $0 <<< "SWIFT_EXEC = " <<< swiftCompilerPath
+ let swiftCompilerPath = Resources.default.swiftCompiler
+
+ // Override path to the Swift compiler.
+ let stream = BufferedOutputByteStream()
+ stream <<< "SWIFT_EXEC = " <<< swiftCompilerPath.asString <<< "\n"
+
+ // Override Swift libary path, if present.
+ let swiftLibraryPath = resolveSymlinks(swiftCompilerPath).appending(components: "..", "..", "lib", "swift", "macosx")
+ if localFileSystem.exists(swiftCompilerPath) {
+ stream <<< "SWIFT_LIBRARY_PATH = " <<< swiftLibraryPath.asString <<< "\n"
  }
+ try localFileSystem.writeFileContents(xcconfig, bytes: stream.bytes)
+
  try Process.checkNonZeroExit(
  args: "xcodebuild", "-project", project.asString, "-alltargets", "-xcconfig", xcconfig.asString, environment: env)
  } catch {