Leveraging Xcode Code Coverage

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Leveraging Xcode Code Coverage Simone Civetta Monday, 13th July - Minsk, Belarus

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What is Code Coverage?

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Testing

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Metric that measures the value of your tests

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Code Coverage detects ☞ Which code is executing when we're running the tests ☞ Which code is untested

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How does it work? ☞ The information is gathered in two steps ☞ compile time ☞ runtime ☞ Tools count each expression that is executed

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Code coverage on iOS

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Code coverage on iOS until last month

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Objective-C

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Swift

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Swift

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How it worked ☞ LLVM creates annotation and data ﬁles: ☞ .gcno ☞ .gcda

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How to enable in Xcode

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How to enable via command line

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GCC_INSTRUMENT_PROGRAM_FLOW_ARCS=YES GCC_GENERATE_TEST_COVERAGE_FILES=YES xcodebuild [...] test

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Tools

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Tools ☞ Coverstory ☞ gcovr ☞ lcov ☞ Slather

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Slather Exports to: - HTML - Gutter JSON - Cobertura XML github.com/venmo/Slather

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But, also

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Swiftcov swiftcov github.com/realm/SwiftCov ☞ Supports gcov format ☞ Uses breakpoints to gather coverage data

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Code coverage on iOS

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Code coverage on iOS since last month

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Objective-C

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Swift

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A new format ☞ gcov ☞ profdata

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Xcode generates profdata ﬁles for ☞ Swift ☞ ...and Objective-C

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How to enable in Xcode

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How to enable via command line

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xcodebuild [...] test -enableCodeCoverage YES

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xcodebuild -scheme MoDevByProject -destination "name=iPhone 6,OS=latest" -enableCodeCoverage YES test

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Exploiting the data ☞ llvm-cov

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Exploiting the data $XCODE_PATH/Toolchains/XcodeDefault.xctoolchain/usr/bin/llvm-cov show -instr-profile MY_PROJECT_PROFDATA MY_PROJECT_BINARY_FILE

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Tools

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Tools ☞ Slather ☞ Xcode Server

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Slather github.com/venmo/slather/pull/92

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Xcode Server

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Summing up

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Doesn't tell you if your code is bad ...

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Doesn't tell you if your code is bad But can help writing better code

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You're just minutes away from collecting Code Coverage info for Swift Start soon!