Using Package Manager Resources in Swift PM Unit Tests

[karimhm]

Currently, in order to have successful tests when using the Swift Package Manager the gettysburgaddress.txt file is copied manually to the unit test bundle resources folder.

gtm-session-fetcher/Source/UnitTests/GTMSessionFetcherFetchingTest.m

Lines 94 to 126 in 83e8f3c

	#if SWIFT_PACKAGE
	// Swift Pacage Manager does not support resources distribution currently,
	// therefore the "gettysburgaddress.txt" file must be copied manually to the test bundle.
	static dispatch_once_t onceToken;
	dispatch_once(&onceToken, ^{
	NSString *gettysburg = @""\
	"Four score and seven years ago our fathers brought forth on this continent, a"\
	"new nation, conceived in liberty, and dedicated to the proposition that all men"\
	"are created equal.";
	NSString * resourcePath = [testBundle resourcePath];
	XCTAssertNotNil(resourcePath);
	if (![[NSFileManager defaultManager] fileExistsAtPath:resourcePath]) {
	NSError *createDirectoryError = nil;
	if (![[NSFileManager defaultManager] createDirectoryAtPath:resourcePath
	withIntermediateDirectories:true
	attributes:nil
	error:&createDirectoryError]) {
	XCTFail("Failed to create the Resources directory, error: %@", createDirectoryError);
	}
	}
	NSString *gettysburgPath = [resourcePath stringByAppendingPathComponent:@"gettysburgaddress.txt"];
	NSError *writeError = nil;
	if (![gettysburg writeToFile:gettysburgPath
	atomically:true
	encoding:NSUTF8StringEncoding
	error:&writeError]) {
	XCTFail("Failed to write `gettysburgaddress.txt` bundle Resource, error: %@", writeError);
	}
	});
	#endif

Swift 5.3 introduced a new feature called Package Manager Resources. Once this gets rolled into production, it must be used to copy resources rather than doing it manually.

[thomasvl]

I have an attempt at this in https://github.com/thomasvl/gtm-session-fetcher/tree/swiftpm_updates.

• For some reason, one has to add excludes for lots of things even when one has sources or resources entry. Sorta feels odd to have to list what's both in and out, instead of having to do one or the other.
• The tests fail from the command line. If I open the Package.swift Xcode is good, but swift test fails with the resource bundle apparently always being nil.

[karimhm]

The tests might be failing due to SR-12912. The following PR (#2905) should solve it.

[thomasvl]

I also posted on the Swift Forums about this and they also pointed at that PR, but I'm not sure if it is the same problem. That fix shows the old code path calling fatalError if it can't make the Bundle, but I'm not crashing, I'm getting back nil in the ObjC code.

[karimhm]

We should file a new bug then. XMPPFramework #1177 suffer from the same issue.

[thomasvl]

Opened https://bugs.swift.org/browse/SR-13560 also.

[karimhm]

@thomasvl One workaround iI recently knew about is to use xcodebuild to test Swift packages rather than the swift tool. The resources issue (SR-13560) seem to be present inside swift tool only.

Example:

xcodebuild -scheme GTMSessionFetcher-Package -destination "name=iPhone 11 Pro" test