Add additional CXX tests

Author: ncooke3

Fixtures/MixedTargets/BasicMixedTargets/Package.swift

@@ -102,8 +102,10 @@ let package = Package(
         // In order to import this target into downstream targets, two
         // additional things must be done (depending on whether the target is
         // being imported into a Clang vs. Swift context):
-        // - Clang context: The downstream target must pass `-fcxx-modules` 
-        //   and `-fmodules` as unsafe flags in the target's `cSettings`.
+        // - Clang context: If the client wants to import the module, client
+        //   must pass `-fcxx-modules` and `-fmodules` as unsafe flags in
+        //   the target's `cSettings`. Else, the client can just import
+        //   individual public headers without further configuring the target.
         // - Swift context: The mixed target needs to make a custom module
         //   map that only exposes public CXX headers in a non-Swift context.
         //   

Fixtures/MixedTargets/BasicMixedTargets/Sources/MixedTargetWithPublicCXXAPI/Factorial.swift

@@ -1,5 +1,11 @@
 import Foundation
 
+@objc public class Factorial: NSObject {
+    @objc public static func text() -> String {
+        return "Hello, World!"
+    }
+}
+
 public func factorial(_ x: Int32) -> Int {
     return ObjcCalculator.factorial(for: x)
 }

Fixtures/MixedTargets/BasicMixedTargets/Tests/MixedTargetWithPublicCXXAPITests/ObjcMixedTargetWithPublicCXXAPIViaHeaderImportTests

@@ -0,0 +1,26 @@
+#import <XCTest/XCTest.h>
+
+#import "CXXSumFinder.hpp"
+#import "ObjcCalculator.h"
+#import "MixedTargetWithPublicCXXAPI-Swift.h"
+
+@interface ObjcMixedTargetWithPublicCXXAPIViaModuleImportTests : XCTestCase
+@end
+
+@implementation ObjcMixedTargetWithPublicCXXAPIViaModuleImportTests
+
+- (void)testPublicObjcAPI {
+    XCTAssertEqual([ObjcCalculator factorialForInt:5], 120);
+    XCTAssertEqual([ObjcCalculator sumX:1 andY:2], 3);
+}
+
+- (void)testPublicSwiftAPI {
+    XCTAssertEqualObjects([Factorial text], @"Hello, World!");
+}
+
+- (void)testPublicCXXAPI {
+    CXXSumFinder sf;
+    XCTAssertEqual(sf.sum(1,2), 3);
+}
+
+@end

Fixtures/MixedTargets/BasicMixedTargets/Tests/MixedTargetWithPublicCXXAPITests/ObjcMixedTargetWithPublicCXXAPITests.mm renamed to Fixtures/MixedTargets/BasicMixedTargets/Tests/MixedTargetWithPublicCXXAPITests/ObjcMixedTargetWithPublicCXXAPIViaModuleImportTests.mm

@@ -2,16 +2,20 @@
 
 @import MixedTargetWithPublicCXXAPI;
 
-@interface ObjcMixedTargetWithPublicCXXAPITests : XCTestCase
+@interface ObjcMixedTargetWithPublicCXXAPIViaModuleImportTests : XCTestCase
 @end
 
-@implementation ObjcMixedTargetWithPublicCXXAPITests
+@implementation ObjcMixedTargetWithPublicCXXAPIViaModuleImportTests
 
 - (void)testPublicObjcAPI {
     XCTAssertEqual([ObjcCalculator factorialForInt:5], 120);
     XCTAssertEqual([ObjcCalculator sumX:1 andY:2], 3);
 }
 
+- (void)testPublicSwiftAPI {
+    XCTAssertEqualObjects([Factorial text], @"Hello, World!");
+}
+
 - (void)testPublicCXXAPI {
     CXXSumFinder sf;
     XCTAssertEqual(sf.sum(1,2), 3);

Tests/FunctionalTests/MixedTargetTests.swift

@@ -150,7 +150,11 @@ final class MixedTargetTests: XCTestCase {
         try fixture(name: "MixedTargets/BasicMixedTargets") { fixturePath in
             XCTAssertBuilds(
                 fixturePath,
-                extraArgs: ["--target", "MixedTargetWithPublicCXXAPITests"]
+                extraArgs: ["--target", "MixedTargetWithPublicCXXAPI"]
+            )
+            XCTAssertSwiftTest(
+                fixturePath,
+                extraArgs: ["--filter", "MixedTargetWithPublicCXXAPITests"]
             )
         }
     }