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//===--- Filter.swift - tests for lazy filtering --------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
// RUN: %target-run-simple-swift
// REQUIRES: executable_test
import StdlibUnittest
let FilterTests = TestSuite("Filter")
// Check that the generic parameter is called 'Base'.
protocol TestProtocol1 {}
extension LazyFilterIterator where Base : TestProtocol1 {
var _baseIsTestProtocol1: Bool {
fatalError("not implemented")
}
}
extension LazyFilterSequence where Base : TestProtocol1 {
var _baseIsTestProtocol1: Bool {
fatalError("not implemented")
}
}
extension LazyFilterCollection where Base : TestProtocol1 {
var _baseIsTestProtocol1: Bool {
fatalError("not implemented")
}
}
FilterTests.test("filtering collections") {
let f0 = LazyFilterCollection(_base: 0..<30) { $0 % 7 == 0 }
expectEqualSequence([0, 7, 14, 21, 28], f0)
let f1 = LazyFilterCollection(_base: 1..<30) { $0 % 7 == 0 }
expectEqualSequence([7, 14, 21, 28], f1)
}
FilterTests.test("filtering sequences") {
let f0 = (0..<30).makeIterator().lazy.filter { $0 % 7 == 0 }
expectEqualSequence([0, 7, 14, 21, 28], f0)
let f1 = (1..<30).makeIterator().lazy.filter { $0 % 7 == 0 }
expectEqualSequence([7, 14, 21, 28], f1)
}
FilterTests.test("single-count") {
// Check that we're only calling a lazy filter's predicate one time for
// each element in a sequence or collection.
var count = 0
let mod7AndCount: (Int) -> Bool = {
count += 1
return $0 % 7 == 0
}
let f0 = (0..<30).makeIterator().lazy.filter(mod7AndCount)
_ = Array(f0)
expectEqual(30, count)
count = 0
let f1 = LazyFilterCollection(_base: 0..<30, mod7AndCount)
_ = Array(f1)
expectEqual(30, count)
}
FilterTests.test("chained filter order") {
let array = [1]
let lazyFilter = array.lazy
.filter { _ in false }
.filter { _ in
expectUnreachable("Executed second filter before first")
return true
}
let lazyResult = Array(lazyFilter)
let result = array
.filter { _ in false }
.filter { _ in
expectUnreachable("Executed second filter before first")
return true
}
expectEqual(lazyResult.count, 0)
expectEqual(result.count, 0)
}
runAllTests()
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