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$ otool -L .build/debug/ios-framework-packagePackageTests.xctest/Contents/MacOS/ios-framework-packagePackageTests
  /usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 228.0.0)
  /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.200.5)
======
  /System/Library/Frameworks/UIKit.framework/UIKit (compatibility version 1.0.0, current version 61000.0.0)
======
  @rpath/XCTest.framework/Versions/A/XCTest (compatibility version 1.0.0, current version 14460.20.0)
  @rpath/libswiftCore.dylib (compatibility version 1.0.0, current version 1000.11.42)
  @rpath/libswiftCoreFoundation.dylib (compatibility version 1.0.0, current version 1000.11.42)
  @rpath/libswiftCoreGraphics.dylib (compatibility version 1.0.0, current version 1000.11.42)

dive

Compile Swift Module 'ios_framework_package' (1 sources)
Compile Swift Module 'ios_framework_packageTests' (2 sources)
Linking ./.build/x86_64-apple-macosx10.10/debug/ios-framework-packagePackageTests.xctest/Contents/MacOS/ios-framework-packagePackageTests
xctest[77129:8746476] 
  The bundle "ios-framework-packagePackageTests.xctest" couldn't be loaded because it is damaged \
  or missing necessary resources. Try reinstalling the bundle.
xctest[77129:8746476](dlopen_preflight(.build/x86_64-apple-macosx10.10/debug/ios-framework-packagePackageTests.xctest/Contents/MacOS/ios-framework-packagePackageTests):

**Library not loaded: /System/Library/Frameworks/UIKit.framework/UIKit**

dive

swift test \
 -Xswiftc "-sdk" -Xswiftc "`xcrun --sdk iphonesimulator --show-sdk-path`" \
 -Xswiftc "-target" -Xswiftc "x86_64-apple-ios12.1-simulator"

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$ nm -extern-only -defined-only -just-symbol-name .build/x86_64-apple-macosx10.10/debug/ios_framework_package.build/ios_framework_package.swift.o 
_$S12CoreGraphics7CGFloatVACSBAAWL
_$S12CoreGraphics7CGFloatVACSBAAWl
_$S12CoreGraphics7CGFloatVACSLAAWL
_$S12CoreGraphics7CGFloatVACSLAAWl
_$S21ios_framework_package16FrameworkPackageC11randomColorSo7UIColorCyF
_$S21ios_framework_package16FrameworkPackageCACycfC
_$S21ios_framework_package16FrameworkPackageCACycfc
_$S21ios_framework_package16FrameworkPackageCMa
_$S21ios_framework_package16FrameworkPackageCMm

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$ lipo -archs .build/x86_64-apple-macosx10.10/debug/ios_framework_package.build/ios_framework_package.swift.o 
x86_64

dive

Compile Swift Module 'ios_framework_package' (1 sources)

dive

swift build \
 -Xswiftc "-sdk" -Xswiftc "`xcrun - sdk iphonesimulator - show-sdk-path`" \
 -Xswiftc "-target" -Xswiftc "x86_64-apple-ios12.1-simulator"

dive

xcrun -sdk macosx -show-sdk-path
xcrun -sdk macosx -show-sdk-platform-path
xcrun -find clang
xcrun -sdk macosx -find xctest
sandbox-exec -p '(version 1)

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Compile Swift Module 'ios_framework_package' (1 sources)
./spm-ios-example/ios-framework-package/Sources/ios-framework-package/ios_framework_package.swift:1:8: 
       error: no such module 'UIKit'
import UIKit
       ^
error: terminated(1): /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift-build-tool 
       -f./spm-ios-example/ios-framework-package/.build/debug.yaml main output: ...

dive

import UIKit
import class ios_framework_package.FrameworkPackage
class ViewController: UIViewController {
override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = FrameworkPackage().randomColor()
    }
    
    @IBAction func pressed(_ button: UIButton) {
        self.view.backgroundColor = FrameworkPackage().randomColor()