How can I build SBTUITestTunnel for a Swift app using Buck?

[sfarbota]

I am trying to use Buck to include the SBTUITestTunnel library in a couple of iOS apps I am working on. This library extends the standard Xcode UI-testing framework to offer additional features such as monitoring network calls. While SBTUITestTunnel is written mostly in Objective-C, The apps I hope to include this library in are written in Swift and use Buck as their build tool. I'd also like to be able to use both Buck and Xcode to execute the tests once I have them written.

Unfortunately, the SBTUITestTunnel Installation/Setup/Usage docs do not seem to provide any guidance on building them with Buck. The repo does include CocoaPods config files, which I have tried to convert to a BUCK file. However, I've been unable to get that working properly after several attempts. I've even tried grabbing the prebuilt .frameworks from the build output of the provided SBTUITestTunnel Example App, but still no luck.

Here are the attempts I've made so far at creating a working BUCK file:

Attempt 1 - Building as Libraries from Source:

Code:

apple_library(
  name = 'SBTUITestTunnelCommon',
  visibility = ['PUBLIC'],
  swift_version = '5',
  exported_headers = glob([
    'Pod/Common/**/*.h',
  ]),
  srcs = glob([
    'Pod/Common/**/*.swift',
    'Pod/Common/**/*.m',
  ]),
  deps = [
    '//Path/GCDWebServer:GCDWebServer',
  ]
)

apple_library(
  name = 'SBTUITestTunnelClient',
  visibility = ['PUBLIC'],
  swift_version = '5',
  exported_headers = glob([
    'Pod/Client/**/*.h',
  ]),
  srcs = glob([
    'Pod/Client/**/*.swift',
    'Pod/Client/**/*.m',
  ]),
  deps = [
    '//Path/GCDWebServer:GCDWebServer',
    '//Path/SBTUITestTunnel:SBTUITestTunnelCommon',
  ]
)

apple_library(
  name = 'SBTUITestTunnelServer',
  visibility = ['PUBLIC'],
  swift_version = '5',
  exported_headers = glob([
    'Pod/Server/**/*.h',
  ]),
  srcs = glob([
    'Pod/Server/**/*.swift',
    'Pod/Server/**/*.m',
  ]),
  deps = [
    '//Path/GCDWebServer:GCDWebServer',
    '//Path/SBTUITestTunnel:SBTUITestTunnelCommon',
  ]
)

Result:

Buck build completes successfully, but running tests in Buck and trying to build in Xcode both fail due with errors like this one (when trying to run @import SBTUITestTunnelCommon; from a file in the SBTUITestTunnelServer class):

Module 'SBTUITestTunnelCommon' not found

Attempt 2 - Building as Frameworks from Source:

Code:

sbt_ui_test_tunnel_common_bundle_name = 'SBTUITestTunnelCommon'
sbt_ui_test_tunnel_common_binary_name = sbt_ui_test_tunnel_common_bundle_name + 'Binary'
sbt_ui_test_tunnel_common_module_name = sbt_ui_test_tunnel_common_bundle_name
sbt_ui_test_tunnel_common_product_name = sbt_ui_test_tunnel_common_bundle_name
# Copied `Info.plist` from the Example app to this Pod folder:
sbt_ui_test_tunnel_common_info_plist = 'Pod/Common/' + sbt_ui_test_tunnel_common_bundle_name + '-Info.plist'

sbt_ui_test_tunnel_client_bundle_name = 'SBTUITestTunnelClient'
sbt_ui_test_tunnel_client_binary_name = sbt_ui_test_tunnel_client_bundle_name + 'Binary'
sbt_ui_test_tunnel_client_module_name = sbt_ui_test_tunnel_client_bundle_name
sbt_ui_test_tunnel_client_product_name = sbt_ui_test_tunnel_client_bundle_name
# Copied `Info.plist` from the Example app to this Pod folder:
sbt_ui_test_tunnel_client_info_plist = 'Pod/Client/' + sbt_ui_test_tunnel_client_bundle_name + '-Info.plist'

sbt_ui_test_tunnel_server_bundle_name = 'SBTUITestTunnelServer'
sbt_ui_test_tunnel_server_binary_name = sbt_ui_test_tunnel_server_bundle_name + 'Binary'
sbt_ui_test_tunnel_server_module_name = sbt_ui_test_tunnel_server_bundle_name
sbt_ui_test_tunnel_server_product_name = sbt_ui_test_tunnel_server_bundle_name
# Copied `Info.plist` from the Example app to this Pod folder:
sbt_ui_test_tunnel_server_info_plist = 'Pod/Server/' + sbt_ui_test_tunnel_server_bundle_name + '-Info.plist'

apple_binary(
  name = sbt_ui_test_tunnel_common_binary_name,
  visibility = ['PUBLIC'],
  module_name = sbt_ui_test_tunnel_common_module_name,
  swift_version = '5',
  linker_flags = [
    '-ObjC', # Have tried with and without this
  ],
  link_style = 'shared',
  exported_headers = glob([
    'Pod/Common/**/*.h',
  ]),
  srcs = glob([
    'Pod/Common/**/*.swift',
    'Pod/Common/**/*.m',
  ]),
  deps = [
    '//Path/GCDWebServer:GCDWebServer',
  ]
)

apple_bundle(
  name = sbt_ui_test_tunnel_common_bundle_name,
  visibility = ['PUBLIC'],
  product_name = sbt_ui_test_tunnel_common_product_name,
  binary = ':' + sbt_ui_test_tunnel_common_binary_name,
  extension = 'framework',
  xcode_product_type = 'com.apple.product-type.framework',
  info_plist = sbt_ui_test_tunnel_common_info_plist,
)

apple_binary(
  name = sbt_ui_test_tunnel_client_binary_name,
  visibility = ['PUBLIC'],
  module_name = sbt_ui_test_tunnel_client_module_name,
  swift_version = '5',
  linker_flags = [
    '-ObjC', # Have tried with and without this
  ],
  link_style = 'shared',
  exported_headers = glob([
    'Pod/Client/**/*.h',
  ]),
  srcs = glob([
    'Pod/Client/**/*.swift',
    'Pod/Client/**/*.m',
  ]),
  deps = [
    '//Path/GCDWebServer:GCDWebServer',
    '//Path/SBTUITestTunnel:' + sbt_ui_test_tunnel_common_binary_name,
  ]
)

apple_bundle(
  name = sbt_ui_test_tunnel_client_bundle_name,
  visibility = ['PUBLIC'],
  product_name = sbt_ui_test_tunnel_client_product_name,
  binary = ':' + sbt_ui_test_tunnel_client_binary_name,
  extension = 'framework',
  xcode_product_type = 'com.apple.product-type.framework',
  info_plist = sbt_ui_test_tunnel_client_info_plist,
)

apple_binary(
  name = sbt_ui_test_tunnel_server_binary_name,
  visibility = ['PUBLIC'],
  module_name = sbt_ui_test_tunnel_server_module_name,
  swift_version = '5',
enter code here
  linker_flags = [
    '-ObjC', # Have tried with and without this
  ],
  link_style = 'shared',
  exported_headers = glob([
    'Pod/Server/**/*.h',
  ]),
  srcs = glob([
    'Pod/Server/**/*.swift',
    'Pod/Server/**/*.m',
  ]),
  deps = [
    '//Path/GCDWebServer:GCDWebServer',
    '//Path/SBTUITestTunnel:' + sbt_ui_test_tunnel_common_binary_name,
  ]
)

apple_bundle(
  name = sbt_ui_test_tunnel_server_bundle_name,
  visibility = ['PUBLIC'],
  product_name = sbt_ui_test_tunnel_server_product_name,
  binary = ':' + sbt_ui_test_tunnel_server_binary_name,
  extension = 'framework',
  xcode_product_type = 'com.apple.product-type.framework',
  info_plist = sbt_ui_test_tunnel_server_info_plist,
)

Result:

Buck build fails with this error message:

Command failed with exit code 1.
stderr: ld: warning: -sdk_version and -platform_version are not compatible, ignoring - 
sdk_version
Undefined symbols for architecture x86_64:
  "_main", referenced from:
     implicit entry/start for main executable
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Attempt 3 - Building as prebuilt_apple_frameworks:

Code:

sbt_ui_test_tunnel_common_framework_name = 'SBTUITestTunnelCommon'
# Copied .framework file from build output of the Example app to this Frameworks folder:
sbt_ui_test_tunnel_common_framework_path = 'Frameworks/' + sbt_ui_test_tunnel_common_framework_name + '/' + sbt_ui_test_tunnel_common_framework_name + '.framework'

sbt_ui_test_tunnel_client_framework_name = 'SBTUITestTunnelClient'
# Copied .framework file from build output of the Example app to this Frameworks folder:
sbt_ui_test_tunnel_client_framework_path = 'Frameworks/' + sbt_ui_test_tunnel_common_framework_name + '/' + sbt_ui_test_tunnel_common_framework_name + '.framework'

sbt_ui_test_tunnel_server_framework_name = 'SBTUITestTunnelServer'
# Copied .framework file from build output of the Example app to this Frameworks folder:
sbt_ui_test_tunnel_server_framework_path = 'Frameworks/' + sbt_ui_test_tunnel_common_framework_name + '/' + sbt_ui_test_tunnel_common_framework_name + '.framework'

prebuilt_apple_framework(
  name = sbt_ui_test_tunnel_common_framework_name,
  framework = sbt_ui_test_tunnel_common_framework_path,
  preferred_linkage = 'stat',
  visibility = [
    'PUBLIC'
  ],
  deps = [
    '//Path/GCDWebServer:GCDWebServer',
  ],
)

prebuilt_apple_framework(
  name = sbt_ui_test_tunnel_client_framework_name,
  framework = sbt_ui_test_tunnel_client_framework_path,
  preferred_linkage = 'shared',
  visibility = [
    'PUBLIC'
  ],
  deps = [
    '//Path/GCDWebServer:GCDWebServer',
    '//Path/SBTUITestTunnel:' + sbt_ui_test_tunnel_common_framework_name,
  ],
)

prebuilt_apple_framework(
  name = sbt_ui_test_tunnel_server_framework_name,
  framework = sbt_ui_test_tunnel_server_framework_path,
  preferred_linkage = 'shared',
  visibility = [
    'PUBLIC'
  ],
  deps = [
    '//Path/GCDWebServer:GCDWebServer',
    '//Path/SBTUITestTunnel:' + sbt_ui_test_tunnel_common_framework_name,
  ],
)

Result:

Buck build fails with this error message:

Command failed with exit code 1.
stderr: /Users/me/path/BridgingHeader.h:12:9: error: 'SBTUITestTunnelServer/SBTUITestTunnelServer.h' file not found
#import <SBTUITestTunnelServer/SBTUITestTunnelServer.h>
        ^
<unknown>:0: error: failed to import bridging header 'path/BridgingHeader.h'

Additional Notes:

• I've followed all steps in the docs, including setting the DEBUG/DEBUG=1 settings and adding the necessary dependencies in the BridgingHeaders.h files like so:

  • In the Bridging Header file for the library that is to be tested:

    #import <SBTUITestTunnelCommon/SBTUITestTunnelCommon.h>
    #import <SBTUITestTunnelServer/SBTUITestTunnelServer.h>

  • And in the Bridging Header file for the library that has the tests:

    #import <SBTUITestTunnelClient/SBTUITunneledApplication.h>
    #import <SBTUITestTunnelClient/XCTestCase+AppExtension.h>
    #import <SBTUITestTunnelCommon/SBTUITestTunnelCommon.h> // Have tried with and without this line

• I included the SBTUITestTunnel libraries/frameworks as dependencies in my main app's BUCK file like this:

      apple_library(
        ...
        bridging_header = 'BridgingHeader.h',
        deps = [
          '//Path/SBTUITestTunnel:SBTUITestTunnelCommon',
          '//Path/SBTUITestTunnel:SBTUITestTunnelServer',
          '//Path/GCDWebServer:GCDWebServer',
        ]
      )
  
      apple_test(
        ...
        bridging_header = 'UITests/BridgingHeader.h',
        deps = [
          '//Path/SBTUITestTunnel:SBTUITestTunnelClient',
        ]
      )

• SBTUITestTunnel depends on another library, GCDWebServer, which also does not provide a BUCK file. However, I have been able to get that one working with using this:

  apple_library(
    name = 'GCDWebServer',
    visibility = ['PUBLIC'],
    swift_version = '5',
    exported_headers = glob([
      'GCDWebServer/**/*.h',
    ]),
    srcs = glob([
      'GCDWebServer/**/*.swift',
      'GCDWebServer/**/*.m',
    ])
  )
  
  apple_library(
    name = 'GCDWebDAVServer',
    visibility = ['PUBLIC'],
    swift_version = '5',
    exported_headers = glob([
      'GCDWebDAVServer/**/*.h',
    ]),
    srcs = glob([
      'GCDWebDAVServer/*.swift',
      'GCDWebDAVServer/*.m',
    ]),
    deps = [
      '//Path/GCDWebServer:GCDWebServer',
    ]
  )
  
  apple_library(
    name = 'GCDWebUploader',
    visibility = ['PUBLIC'],
    swift_version = '5',
    exported_headers = glob([
      'GCDWebUploader/**/*.h',
    ]),
    srcs = glob([
      'GCDWebUploader/**/*.swift',
      'GCDWebUploader/**/*.m',
    ]),
    deps = [
      '//Path/GCDWebServer:GCDWebServer',
    ]
  )

Any idea what I am doing wrong? Or at least maybe some advice on which of these options is most likely the best path?

[sfarbota]

FYI, I've also asked the same question in a couple other places:

• https://github.com/Subito-it/SBTUITestTunnel/issues/94
• https://stackoverflow.com/q/61138705/170309