ReactiveCocoaFramework/ReactiveCocoaTests/RACStreamExamples.m - nest-mobile-client-iphone/5.0.0/ReactiveCocoa - Git at Google

 //
 //  RACStreamExamples.m
 //  ReactiveCocoa
 //
 //  Created by Justin Spahr-Summers on 2012-11-01.
 //  Copyright (c) 2012 GitHub, Inc. All rights reserved.
 //

 #import "RACStreamExamples.h"

 #import "RACStream.h"
 #import "RACUnit.h"
 #import "RACTuple.h"

 NSString * const RACStreamExamples = @"RACStreamExamples";
 NSString * const RACStreamExamplesClass = @"RACStreamExamplesClass";
 NSString * const RACStreamExamplesInfiniteStream = @"RACStreamExamplesInfiniteStream";
 NSString * const RACStreamExamplesVerifyValuesBlock = @"RACStreamExamplesVerifyValuesBlock";

 SharedExampleGroupsBegin(RACStreamExamples)

 sharedExamplesFor(RACStreamExamples, ^(NSDictionary *data) {
 	__block Class streamClass;
 	__block void (^verifyValues)(RACStream *, NSArray *);
 	__block RACStream *infiniteStream;

 	__block RACStream *(^streamWithValues)(NSArray *);

 	before(^{
 		streamClass = data[RACStreamExamplesClass];
 		verifyValues = data[RACStreamExamplesVerifyValuesBlock];
 		infiniteStream = data[RACStreamExamplesInfiniteStream];
 		streamWithValues = [^(NSArray *values) {
 			RACStream *stream = [streamClass empty];

 			for (id value in values) {
 				stream = [stream concat:[streamClass return:value]];
 			}

 			return stream;
 		} copy];
 	});

 	it(@"should return an empty stream", ^{
 		RACStream *stream = [streamClass empty];
 		verifyValues(stream, @[]);
 	});

 	it(@"should lift a value into a stream", ^{
 		RACStream *stream = [streamClass return:RACUnit.defaultUnit];
 		verifyValues(stream, @[ RACUnit.defaultUnit ]);
 	});

 	describe(@"-concat:", ^{
 		it(@"should concatenate two streams", ^{
 			RACStream *stream = [[streamClass return:@0] concat:[streamClass return:@1]];
 			verifyValues(stream, @[ @0, @1 ]);
 		});

 		it(@"should concatenate three streams", ^{
 			RACStream *stream = [[[streamClass return:@0] concat:[streamClass return:@1]] concat:[streamClass return:@2]];
 			verifyValues(stream, @[ @0, @1, @2 ]);
 		});

 		it(@"should concatenate around an empty stream", ^{
 			RACStream *stream = [[[streamClass return:@0] concat:[streamClass empty]] concat:[streamClass return:@2]];
 			verifyValues(stream, @[ @0, @2 ]);
 		});
 	});

 	it(@"should flatten", ^{
 		RACStream *stream = [[streamClass return:[streamClass return:RACUnit.defaultUnit]] flatten];
 		verifyValues(stream, @[ RACUnit.defaultUnit ]);
 	});

 	describe(@"-bind:", ^{
 		it(@"should return the result of binding a single value", ^{
 			RACStream *stream = [[streamClass return:@0] bind:^{
 				return ^(NSNumber *value, BOOL *stop) {
 					NSNumber *newValue = @(value.integerValue + 1);
 					return [streamClass return:newValue];
 				};
 			}];

 			verifyValues(stream, @[ @1 ]);
 		});

 		it(@"should concatenate the result of binding multiple values", ^{
 			RACStream *baseStream = streamWithValues(@[ @0, @1 ]);
 			RACStream *stream = [baseStream bind:^{
 				return ^(NSNumber *value, BOOL *stop) {
 					NSNumber *newValue = @(value.integerValue + 1);
 					return [streamClass return:newValue];
 				};
 			}];

 			verifyValues(stream, @[ @1, @2 ]);
 		});

 		it(@"should concatenate with an empty result from binding a value", ^{
 			RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
 			RACStream *stream = [baseStream bind:^{
 				return ^(NSNumber *value, BOOL *stop) {
 					if (value.integerValue == 1) return [streamClass empty];

 					NSNumber *newValue = @(value.integerValue + 1);
 					return [streamClass return:newValue];
 				};
 			}];

 			verifyValues(stream, @[ @1, @3 ]);
 		});

 		it(@"should terminate immediately when returning nil", ^{
 			RACStream *stream = [infiniteStream bind:^{
 				return ^ id (id _, BOOL *stop) {
 					return nil;
 				};
 			}];

 			verifyValues(stream, @[]);
 		});

 		it(@"should terminate after one value when setting 'stop'", ^{
 			RACStream *stream = [infiniteStream bind:^{
 				return ^ id (id value, BOOL *stop) {
 					*stop = YES;
 					return [streamClass return:value];
 				};
 			}];

 			verifyValues(stream, @[ RACUnit.defaultUnit ]);
 		});

 		it(@"should terminate immediately when returning nil and setting 'stop'", ^{
 			RACStream *stream = [infiniteStream bind:^{
 				return ^ id (id _, BOOL *stop) {
 					*stop = YES;
 					return nil;
 				};
 			}];

 			verifyValues(stream, @[]);
 		});

 		it(@"should be restartable even with block state", ^{
 			NSArray *values = @[ @0, @1, @2 ];
 			RACStream *baseStream = streamWithValues(values);

 			RACStream *countingStream = [baseStream bind:^{
 				__block NSUInteger counter = 0;

 				return ^(id x, BOOL *stop) {
 					return [streamClass return:@(counter++)];
 				};
 			}];

 			verifyValues(countingStream, @[ @0, @1, @2 ]);
 			verifyValues(countingStream, @[ @0, @1, @2 ]);
 		});

 		it(@"should be interleavable even with block state", ^{
 			NSArray *values = @[ @0, @1, @2 ];
 			RACStream *baseStream = streamWithValues(values);

 			RACStream *countingStream = [baseStream bind:^{
 				__block NSUInteger counter = 0;

 				return ^(id x, BOOL *stop) {
 					return [streamClass return:@(counter++)];
 				};
 			}];

 			// Just so +zip:reduce: thinks this is a unique stream.
 			RACStream *anotherStream = [[streamClass empty] concat:countingStream];

 			RACStream *zipped = [streamClass zip:@[ countingStream, anotherStream ] reduce:^(NSNumber *v1, NSNumber *v2) {
 				return @(v1.integerValue + v2.integerValue);
 			}];

 			verifyValues(zipped, @[ @0, @2, @4 ]);
 		});
 	});

 	describe(@"-flattenMap:", ^{
 		it(@"should return a single mapped result", ^{
 			RACStream *stream = [[streamClass return:@0] flattenMap:^(NSNumber *value) {
 				NSNumber *newValue = @(value.integerValue + 1);
 				return [streamClass return:newValue];
 			}];

 			verifyValues(stream, @[ @1 ]);
 		});

 		it(@"should concatenate the results of mapping multiple values", ^{
 			RACStream *baseStream = streamWithValues(@[ @0, @1 ]);
 			RACStream *stream = [baseStream flattenMap:^(NSNumber *value) {
 				NSNumber *newValue = @(value.integerValue + 1);
 				return [streamClass return:newValue];
 			}];

 			verifyValues(stream, @[ @1, @2 ]);
 		});

 		it(@"should concatenate with an empty result from mapping a value", ^{
 			RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
 			RACStream *stream = [baseStream flattenMap:^(NSNumber *value) {
 				if (value.integerValue == 1) return [streamClass empty];

 				NSNumber *newValue = @(value.integerValue + 1);
 				return [streamClass return:newValue];
 			}];

 			verifyValues(stream, @[ @1, @3 ]);
 		});

 		it(@"should treat nil streams like empty streams", ^{
 			RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
 			RACStream *stream = [baseStream flattenMap:^ RACStream * (NSNumber *value) {
 				if (value.integerValue == 1) return nil;

 				NSNumber *newValue = @(value.integerValue + 1);
 				return [streamClass return:newValue];
 			}];

 			verifyValues(stream, @[ @1, @3 ]);
 		});
 	});

 	it(@"should map", ^{
 		RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
 		RACStream *stream = [baseStream map:^(NSNumber *value) {
 			return @(value.integerValue + 1);
 		}];

 		verifyValues(stream, @[ @1, @2, @3 ]);
 	});

 	it(@"should map and replace", ^{
 		RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
 		RACStream *stream = [baseStream mapReplace:RACUnit.defaultUnit];

 		verifyValues(stream, @[ RACUnit.defaultUnit, RACUnit.defaultUnit, RACUnit.defaultUnit ]);
 	});

 	it(@"should filter", ^{
 		RACStream *baseStream = streamWithValues(@[ @0, @1, @2, @3, @4, @5, @6 ]);
 		RACStream *stream = [baseStream filter:^ BOOL (NSNumber *value) {
 			return value.integerValue % 2 == 0;
 		}];

 		verifyValues(stream, @[ @0, @2, @4, @6 ]);
 	});

 	describe(@"-ignore:", ^{
 		it(@"should ignore a value", ^{
 			RACStream *baseStream = streamWithValues(@[ @0, @1, @2, @3, @4, @5, @6 ]);
 			RACStream *stream = [baseStream ignore:@1];

 			verifyValues(stream, @[ @0, @2, @3, @4, @5, @6 ]);
 		});

 		it(@"should ignore based on object equality", ^{
 			RACStream *baseStream = streamWithValues(@[ @"0", @"1", @"2", @"3", @"4", @"5", @"6" ]);

 			NSMutableString *valueToIgnore = [[NSMutableString alloc] init];
 			[valueToIgnore appendString:@"1"];
 			RACStream *stream = [baseStream ignore:valueToIgnore];

 			verifyValues(stream, @[ @"0", @"2", @"3", @"4", @"5", @"6" ]);
 		});
 	});

 	it(@"should start with a value", ^{
 		RACStream *stream = [[streamClass return:@1] startWith:@0];
 		verifyValues(stream, @[ @0, @1 ]);
 	});

 	describe(@"-skip:", ^{
 		__block NSArray *values;
 		__block RACStream *stream;

 		before(^{
 			values = @[ @0, @1, @2 ];
 			stream = streamWithValues(values);
 		});

 		it(@"should skip any valid number of values", ^{
 			for (NSUInteger i = 0; i < values.count; i++) {
 				verifyValues([stream skip:i], [values subarrayWithRange:NSMakeRange(i, values.count - i)]);
 			}
 		});

 		it(@"should return an empty stream when skipping too many values", ^{
 			verifyValues([stream skip:4], @[]);
 		});
 	});

 	describe(@"-take:", ^{
 		describe(@"with three values", ^{
 			__block NSArray *values;
 			__block RACStream *stream;

 			before(^{
 				values = @[ @0, @1, @2 ];
 				stream = streamWithValues(values);
 			});

 			it(@"should take any valid number of values", ^{
 				for (NSUInteger i = 0; i < values.count; i++) {
 					verifyValues([stream take:i], [values subarrayWithRange:NSMakeRange(0, i)]);
 				}
 			});

 			it(@"should return the same stream when taking too many values", ^{
 				verifyValues([stream take:4], values);
 			});
 		});

 		it(@"should take and terminate from an infinite stream", ^{
 			verifyValues([infiniteStream take:0], @[]);
 			verifyValues([infiniteStream take:1], @[ RACUnit.defaultUnit ]);
 			verifyValues([infiniteStream take:2], @[ RACUnit.defaultUnit, RACUnit.defaultUnit ]);
 		});

 		it(@"should take and terminate from a single-item stream", ^{
 			NSArray *values = @[ RACUnit.defaultUnit ];
 			RACStream *stream = streamWithValues(values);
 			verifyValues([stream take:1], values);
 		});
 	});

 	describe(@"zip stream creation methods", ^{
 		__block NSArray *valuesOne;

 		__block RACStream *streamOne;
 		__block RACStream *streamTwo;
 		__block RACStream *streamThree;
 		__block NSArray *threeStreams;

 		__block NSArray *oneStreamTuples;
 		__block NSArray *twoStreamTuples;
 		__block NSArray *threeStreamTuples;

 		before(^{
 			valuesOne = @[ @"Ada", @"Bob", @"Dea" ];
 			NSArray *valuesTwo = @[ @"eats", @"cooks", @"jumps" ];
 			NSArray *valuesThree = @[ @"fish", @"bear", @"rock" ];

 			streamOne = streamWithValues(valuesOne);
 			streamTwo = streamWithValues(valuesTwo);
 			streamThree = streamWithValues(valuesThree);
 			threeStreams = @[ streamOne, streamTwo, streamThree ];

 			oneStreamTuples = @[
 				RACTuplePack(valuesOne[0]),
 				RACTuplePack(valuesOne[1]),
 				RACTuplePack(valuesOne[2]),
 			];

 			twoStreamTuples = @[
 				RACTuplePack(valuesOne[0], valuesTwo[0]),
 				RACTuplePack(valuesOne[1], valuesTwo[1]),
 				RACTuplePack(valuesOne[2], valuesTwo[2]),
 			];

 			threeStreamTuples = @[
 				RACTuplePack(valuesOne[0], valuesTwo[0], valuesThree[0]),
 				RACTuplePack(valuesOne[1], valuesTwo[1], valuesThree[1]),
 				RACTuplePack(valuesOne[2], valuesTwo[2], valuesThree[2]),
 			];
 		});

 		describe(@"-zipWith:", ^{
 			it(@"should make a stream of tuples", ^{
 				RACStream *stream = [streamOne zipWith:streamTwo];
 				verifyValues(stream, twoStreamTuples);
 			});

 			it(@"should truncate streams", ^{
 				RACStream *shortStream = streamWithValues(@[ @"now", @"later" ]);
 				RACStream *stream = [streamOne zipWith:shortStream];

 				verifyValues(stream, @[
 					RACTuplePack(valuesOne[0], @"now"),
 					RACTuplePack(valuesOne[1], @"later")
 				]);
 			});

 			it(@"should work on infinite streams", ^{
 				RACStream *stream = [streamOne zipWith:infiniteStream];
 				verifyValues(stream, @[
 					RACTuplePack(valuesOne[0], RACUnit.defaultUnit),
 					RACTuplePack(valuesOne[1], RACUnit.defaultUnit),
 					RACTuplePack(valuesOne[2], RACUnit.defaultUnit)
 				]);
 			});

 			it(@"should handle multiples of the same stream", ^{
 				RACStream *stream = [streamOne zipWith:streamOne];
 				verifyValues(stream, @[
 					RACTuplePack(valuesOne[0], valuesOne[0]),
 					RACTuplePack(valuesOne[1], valuesOne[1]),
 					RACTuplePack(valuesOne[2], valuesOne[2]),
 				]);
 			});
 		});

 		describe(@"+zip:reduce:", ^{
 			it(@"should reduce values", ^{
 				RACStream *stream = [streamClass zip:threeStreams reduce:^ NSString * (id x, id y, id z) {
 					return [NSString stringWithFormat:@"%@ %@ %@", x, y, z];
 				}];
 				verifyValues(stream, @[ @"Ada eats fish", @"Bob cooks bear", @"Dea jumps rock" ]);
 			});

 			it(@"should truncate streams", ^{
 				RACStream *shortStream = streamWithValues(@[ @"now", @"later" ]);
 				NSArray *streams = [threeStreams arrayByAddingObject:shortStream];
 				RACStream *stream = [streamClass zip:streams reduce:^ NSString * (id w, id x, id y, id z) {
 					return [NSString stringWithFormat:@"%@ %@ %@ %@", w, x, y, z];
 				}];
 				verifyValues(stream, @[ @"Ada eats fish now", @"Bob cooks bear later" ]);
 			});

 			it(@"should work on infinite streams", ^{
 				NSArray *streams = [threeStreams arrayByAddingObject:infiniteStream];
 				RACStream *stream = [streamClass zip:streams reduce:^ NSString * (id w, id x, id y, id z) {
 					return [NSString stringWithFormat:@"%@ %@ %@", w, x, y];
 				}];
 				verifyValues(stream, @[ @"Ada eats fish", @"Bob cooks bear", @"Dea jumps rock" ]);
 			});

 			it(@"should handle multiples of the same stream", ^{
 				NSArray *streams = @[ streamOne, streamOne, streamTwo, streamThree, streamTwo, streamThree ];
 				RACStream *stream = [streamClass zip:streams reduce:^ NSString * (id x1, id x2, id y1, id z1, id y2, id z2) {
 					return [NSString stringWithFormat:@"%@ %@ %@ %@ %@ %@", x1, x2, y1, z1, y2, z2];
 				}];
 				verifyValues(stream, @[ @"Ada Ada eats fish eats fish", @"Bob Bob cooks bear cooks bear", @"Dea Dea jumps rock jumps rock" ]);
 			});
 		});

 		describe(@"+zip:", ^{
 			it(@"should make a stream of tuples out of single value", ^{
 				RACStream *stream = [streamClass zip:@[ streamOne ]];
 				verifyValues(stream, oneStreamTuples);
 			});

 			it(@"should make a stream of tuples out of an array of streams", ^{
 				RACStream *stream = [streamClass zip:threeStreams];
 				verifyValues(stream, threeStreamTuples);
 			});

 			it(@"should make an empty stream if given an empty array", ^{
 				RACStream *stream = [streamClass zip:@[]];
 				verifyValues(stream, @[]);
 			});

 			it(@"should make a stream of tuples out of an enumerator of streams", ^{
 				RACStream *stream = [streamClass zip:threeStreams.objectEnumerator];
 				verifyValues(stream, threeStreamTuples);
 			});

 			it(@"should make an empty stream if given an empty enumerator", ^{
 				RACStream *stream = [streamClass zip:@[].objectEnumerator];
 				verifyValues(stream, @[]);
 			});
 		});
 	});

 	describe(@"+concat:", ^{
 		__block NSArray *streams = nil;
 		__block NSArray *result = nil;

 		before(^{
 			RACStream *a = [streamClass return:@0];
 			RACStream *b = [streamClass empty];
 			RACStream *c = streamWithValues(@[ @1, @2, @3 ]);
 			RACStream *d = [streamClass return:@4];
 			RACStream *e = [streamClass return:@5];
 			RACStream *f = [streamClass empty];
 			RACStream *g = [streamClass empty];
 			RACStream *h = streamWithValues(@[ @6, @7 ]);
 			streams = @[ a, b, c, d, e, f, g, h ];
 			result = @[ @0, @1, @2, @3, @4, @5, @6, @7 ];
 		});

 		it(@"should concatenate an array of streams", ^{
 			RACStream *stream = [streamClass concat:streams];
 			verifyValues(stream, result);
 		});

 		it(@"should concatenate an enumerator of streams", ^{
 			RACStream *stream = [streamClass concat:streams.objectEnumerator];
 			verifyValues(stream, result);
 		});
 	});

 	it(@"should scan", ^{
 		RACStream *stream = streamWithValues(@[ @1, @2, @3, @4 ]);
 		RACStream *scanned = [stream scanWithStart:@0 reduce:^(NSNumber *running, NSNumber *next) {
 			return @(running.integerValue + next.integerValue);
 		}];

 		verifyValues(scanned, @[ @1, @3, @6, @10 ]);
 	});

 	describe(@"taking with a predicate", ^{
 		NSArray *values = @[ @0, @1, @2, @3, @0, @2, @4 ];

 		__block RACStream *stream;

 		before(^{
 			stream = streamWithValues(values);
 		});

 		it(@"should take until a predicate is true", ^{
 			RACStream *taken = [stream takeUntilBlock:^ BOOL (NSNumber *x) {
 				return x.integerValue >= 3;
 			}];

 			verifyValues(taken, @[ @0, @1, @2 ]);
 		});

 		it(@"should take while a predicate is true", ^{
 			RACStream *taken = [stream takeWhileBlock:^ BOOL (NSNumber *x) {
 				return x.integerValue <= 1;
 			}];

 			verifyValues(taken, @[ @0, @1 ]);
 		});

 		it(@"should take a full stream", ^{
 			RACStream *taken = [stream takeWhileBlock:^ BOOL (NSNumber *x) {
 				return x.integerValue <= 10;
 			}];

 			verifyValues(taken, values);
 		});

 		it(@"should return an empty stream", ^{
 			RACStream *taken = [stream takeWhileBlock:^ BOOL (NSNumber *x) {
 				return x.integerValue < 0;
 			}];

 			verifyValues(taken, @[]);
 		});

 		it(@"should terminate an infinite stream", ^{
 			RACStream *infiniteCounter = [infiniteStream scanWithStart:@0 reduce:^(NSNumber *running, id _) {
 				return @(running.unsignedIntegerValue + 1);
 			}];

 			RACStream *taken = [infiniteCounter takeWhileBlock:^ BOOL (NSNumber *x) {
 				return x.integerValue <= 5;
 			}];

 			verifyValues(taken, @[ @1, @2, @3, @4, @5 ]);
 		});
 	});

 	describe(@"skipping with a predicate", ^{
 		NSArray *values = @[ @0, @1, @2, @3, @0, @2, @4 ];

 		__block RACStream *stream;

 		before(^{
 			stream = streamWithValues(values);
 		});

 		it(@"should skip until a predicate is true", ^{
 			RACStream *taken = [stream skipUntilBlock:^ BOOL (NSNumber *x) {
 				return x.integerValue >= 3;
 			}];

 			verifyValues(taken, @[ @3, @0, @2, @4 ]);
 		});

 		it(@"should skip while a predicate is true", ^{
 			RACStream *taken = [stream skipWhileBlock:^ BOOL (NSNumber *x) {
 				return x.integerValue <= 1;
 			}];

 			verifyValues(taken, @[ @2, @3, @0, @2, @4 ]);
 		});

 		it(@"should skip a full stream", ^{
 			RACStream *taken = [stream skipWhileBlock:^ BOOL (NSNumber *x) {
 				return x.integerValue <= 10;
 			}];

 			verifyValues(taken, @[]);
 		});

 		it(@"should finish skipping immediately", ^{
 			RACStream *taken = [stream skipWhileBlock:^ BOOL (NSNumber *x) {
 				return x.integerValue < 0;
 			}];

 			verifyValues(taken, values);
 		});
 	});

 	describe(@"-combinePreviousWithStart:reduce:", ^{
 		NSArray *values = @[ @1, @2, @3 ];
 		__block RACStream *stream;
 		beforeEach(^{
 			stream = streamWithValues(values);
 		});

 		it(@"should pass the previous next into the reduce block", ^{
 			NSMutableArray *previouses = [NSMutableArray array];
 			RACStream *mapped = [stream combinePreviousWithStart:nil reduce:^(id previous, id next) {
 				[previouses addObject:previous ?: RACTupleNil.tupleNil];
 				return next;
 			}];

 			verifyValues(mapped, @[ @1, @2, @3 ]);

 			NSArray *expected = @[ RACTupleNil.tupleNil, @1, @2 ];
 			expect(previouses).to.equal(expected);
 		});

 		it(@"should send the combined value", ^{
 			RACStream *mapped = [stream combinePreviousWithStart:@1 reduce:^(NSNumber *previous, NSNumber *next) {
 				return [NSString stringWithFormat:@"%lu - %lu", (unsigned long)previous.unsignedIntegerValue, (unsigned long)next.unsignedIntegerValue];
 			}];

 			verifyValues(mapped, @[ @"1 - 1", @"1 - 2", @"2 - 3" ]);
 		});
 	});

 	it(@"should reduce tuples", ^{
 		RACStream *stream = streamWithValues(@[
 			RACTuplePack(@"foo", @"bar"),
 			RACTuplePack(@"buzz", @"baz"),
 			RACTuplePack(@"", @"_")
 		]);

 		RACStream *reduced = [stream reduceEach:^(NSString *a, NSString *b) {
 			return [a stringByAppendingString:b];
 		}];

 		verifyValues(reduced, @[ @"foobar", @"buzzbaz", @"_" ]);
 	});
 });

 SharedExampleGroupsEnd
	//
	// RACStreamExamples.m
	// ReactiveCocoa
	//
	// Created by Justin Spahr-Summers on 2012-11-01.
	// Copyright (c) 2012 GitHub, Inc. All rights reserved.
	//

	#import "RACStreamExamples.h"

	#import "RACStream.h"
	#import "RACUnit.h"
	#import "RACTuple.h"

	NSString * const RACStreamExamples = @"RACStreamExamples";
	NSString * const RACStreamExamplesClass = @"RACStreamExamplesClass";
	NSString * const RACStreamExamplesInfiniteStream = @"RACStreamExamplesInfiniteStream";
	NSString * const RACStreamExamplesVerifyValuesBlock = @"RACStreamExamplesVerifyValuesBlock";

	SharedExampleGroupsBegin(RACStreamExamples)

	sharedExamplesFor(RACStreamExamples, ^(NSDictionary *data) {
	__block Class streamClass;
	__block void (^verifyValues)(RACStream , NSArray );
	__block RACStream *infiniteStream;

	__block RACStream (^streamWithValues)(NSArray );

	before(^{
	streamClass = data[RACStreamExamplesClass];
	verifyValues = data[RACStreamExamplesVerifyValuesBlock];
	infiniteStream = data[RACStreamExamplesInfiniteStream];
	streamWithValues = [^(NSArray *values) {
	RACStream *stream = [streamClass empty];

	for (id value in values) {
	stream = [stream concat:[streamClass return:value]];
	}

	return stream;
	} copy];
	});

	it(@"should return an empty stream", ^{
	RACStream *stream = [streamClass empty];
	verifyValues(stream, @[]);
	});

	it(@"should lift a value into a stream", ^{
	RACStream *stream = [streamClass return:RACUnit.defaultUnit];
	verifyValues(stream, @[ RACUnit.defaultUnit ]);
	});

	describe(@"-concat:", ^{
	it(@"should concatenate two streams", ^{
	RACStream *stream = [[streamClass return:@0] concat:[streamClass return:@1]];
	verifyValues(stream, @[ @0, @1 ]);
	});

	it(@"should concatenate three streams", ^{
	RACStream *stream = [[[streamClass return:@0] concat:[streamClass return:@1]] concat:[streamClass return:@2]];
	verifyValues(stream, @[ @0, @1, @2 ]);
	});

	it(@"should concatenate around an empty stream", ^{
	RACStream *stream = [[[streamClass return:@0] concat:[streamClass empty]] concat:[streamClass return:@2]];
	verifyValues(stream, @[ @0, @2 ]);
	});
	});

	it(@"should flatten", ^{
	RACStream *stream = [[streamClass return:[streamClass return:RACUnit.defaultUnit]] flatten];
	verifyValues(stream, @[ RACUnit.defaultUnit ]);
	});

	describe(@"-bind:", ^{
	it(@"should return the result of binding a single value", ^{
	RACStream *stream = [[streamClass return:@0] bind:^{
	return ^(NSNumber value, BOOL stop) {
	NSNumber *newValue = @(value.integerValue + 1);
	return [streamClass return:newValue];
	};
	}];

	verifyValues(stream, @[ @1 ]);
	});

	it(@"should concatenate the result of binding multiple values", ^{
	RACStream *baseStream = streamWithValues(@[ @0, @1 ]);
	RACStream *stream = [baseStream bind:^{
	return ^(NSNumber value, BOOL stop) {
	NSNumber *newValue = @(value.integerValue + 1);
	return [streamClass return:newValue];
	};
	}];

	verifyValues(stream, @[ @1, @2 ]);
	});

	it(@"should concatenate with an empty result from binding a value", ^{
	RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
	RACStream *stream = [baseStream bind:^{
	return ^(NSNumber value, BOOL stop) {
	if (value.integerValue == 1) return [streamClass empty];

	NSNumber *newValue = @(value.integerValue + 1);
	return [streamClass return:newValue];
	};
	}];

	verifyValues(stream, @[ @1, @3 ]);
	});

	it(@"should terminate immediately when returning nil", ^{
	RACStream *stream = [infiniteStream bind:^{
	return ^ id (id _, BOOL *stop) {
	return nil;
	};
	}];

	verifyValues(stream, @[]);
	});

	it(@"should terminate after one value when setting 'stop'", ^{
	RACStream *stream = [infiniteStream bind:^{
	return ^ id (id value, BOOL *stop) {
	*stop = YES;
	return [streamClass return:value];
	};
	}];

	verifyValues(stream, @[ RACUnit.defaultUnit ]);
	});

	it(@"should terminate immediately when returning nil and setting 'stop'", ^{
	RACStream *stream = [infiniteStream bind:^{
	return ^ id (id _, BOOL *stop) {
	*stop = YES;
	return nil;
	};
	}];

	verifyValues(stream, @[]);
	});

	it(@"should be restartable even with block state", ^{
	NSArray *values = @[ @0, @1, @2 ];
	RACStream *baseStream = streamWithValues(values);

	RACStream *countingStream = [baseStream bind:^{
	__block NSUInteger counter = 0;

	return ^(id x, BOOL *stop) {
	return [streamClass return:@(counter++)];
	};
	}];

	verifyValues(countingStream, @[ @0, @1, @2 ]);
	verifyValues(countingStream, @[ @0, @1, @2 ]);
	});

	it(@"should be interleavable even with block state", ^{
	NSArray *values = @[ @0, @1, @2 ];
	RACStream *baseStream = streamWithValues(values);

	RACStream *countingStream = [baseStream bind:^{
	__block NSUInteger counter = 0;

	return ^(id x, BOOL *stop) {
	return [streamClass return:@(counter++)];
	};
	}];

	// Just so +zip:reduce: thinks this is a unique stream.
	RACStream *anotherStream = [[streamClass empty] concat:countingStream];

	RACStream zipped = [streamClass zip:@[ countingStream, anotherStream ] reduce:^(NSNumber v1, NSNumber *v2) {
	return @(v1.integerValue + v2.integerValue);
	}];

	verifyValues(zipped, @[ @0, @2, @4 ]);
	});
	});

	describe(@"-flattenMap:", ^{
	it(@"should return a single mapped result", ^{
	RACStream stream = [[streamClass return:@0] flattenMap:^(NSNumber value) {
	NSNumber *newValue = @(value.integerValue + 1);
	return [streamClass return:newValue];
	}];

	verifyValues(stream, @[ @1 ]);
	});

	it(@"should concatenate the results of mapping multiple values", ^{
	RACStream *baseStream = streamWithValues(@[ @0, @1 ]);
	RACStream stream = [baseStream flattenMap:^(NSNumber value) {
	NSNumber *newValue = @(value.integerValue + 1);
	return [streamClass return:newValue];
	}];

	verifyValues(stream, @[ @1, @2 ]);
	});

	it(@"should concatenate with an empty result from mapping a value", ^{
	RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
	RACStream stream = [baseStream flattenMap:^(NSNumber value) {
	if (value.integerValue == 1) return [streamClass empty];

	NSNumber *newValue = @(value.integerValue + 1);
	return [streamClass return:newValue];
	}];

	verifyValues(stream, @[ @1, @3 ]);
	});

	it(@"should treat nil streams like empty streams", ^{
	RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
	RACStream stream = [baseStream flattenMap:^ RACStream (NSNumber *value) {
	if (value.integerValue == 1) return nil;

	NSNumber *newValue = @(value.integerValue + 1);
	return [streamClass return:newValue];
	}];

	verifyValues(stream, @[ @1, @3 ]);
	});
	});

	it(@"should map", ^{
	RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
	RACStream stream = [baseStream map:^(NSNumber value) {
	return @(value.integerValue + 1);
	}];

	verifyValues(stream, @[ @1, @2, @3 ]);
	});

	it(@"should map and replace", ^{
	RACStream *baseStream = streamWithValues(@[ @0, @1, @2 ]);
	RACStream *stream = [baseStream mapReplace:RACUnit.defaultUnit];

	verifyValues(stream, @[ RACUnit.defaultUnit, RACUnit.defaultUnit, RACUnit.defaultUnit ]);
	});

	it(@"should filter", ^{
	RACStream *baseStream = streamWithValues(@[ @0, @1, @2, @3, @4, @5, @6 ]);
	RACStream stream = [baseStream filter:^ BOOL (NSNumber value) {
	return value.integerValue % 2 == 0;
	}];

	verifyValues(stream, @[ @0, @2, @4, @6 ]);
	});

	describe(@"-ignore:", ^{
	it(@"should ignore a value", ^{
	RACStream *baseStream = streamWithValues(@[ @0, @1, @2, @3, @4, @5, @6 ]);
	RACStream *stream = [baseStream ignore:@1];

	verifyValues(stream, @[ @0, @2, @3, @4, @5, @6 ]);
	});

	it(@"should ignore based on object equality", ^{
	RACStream *baseStream = streamWithValues(@[ @"0", @"1", @"2", @"3", @"4", @"5", @"6" ]);

	NSMutableString *valueToIgnore = [[NSMutableString alloc] init];
	[valueToIgnore appendString:@"1"];
	RACStream *stream = [baseStream ignore:valueToIgnore];

	verifyValues(stream, @[ @"0", @"2", @"3", @"4", @"5", @"6" ]);
	});
	});

	it(@"should start with a value", ^{
	RACStream *stream = [[streamClass return:@1] startWith:@0];
	verifyValues(stream, @[ @0, @1 ]);
	});

	describe(@"-skip:", ^{
	__block NSArray *values;
	__block RACStream *stream;

	before(^{
	values = @[ @0, @1, @2 ];
	stream = streamWithValues(values);
	});

	it(@"should skip any valid number of values", ^{
	for (NSUInteger i = 0; i < values.count; i++) {
	verifyValues([stream skip:i], [values subarrayWithRange:NSMakeRange(i, values.count - i)]);
	}
	});

	it(@"should return an empty stream when skipping too many values", ^{
	verifyValues([stream skip:4], @[]);
	});
	});

	describe(@"-take:", ^{
	describe(@"with three values", ^{
	__block NSArray *values;
	__block RACStream *stream;

	before(^{
	values = @[ @0, @1, @2 ];
	stream = streamWithValues(values);
	});

	it(@"should take any valid number of values", ^{
	for (NSUInteger i = 0; i < values.count; i++) {
	verifyValues([stream take:i], [values subarrayWithRange:NSMakeRange(0, i)]);
	}
	});

	it(@"should return the same stream when taking too many values", ^{
	verifyValues([stream take:4], values);
	});
	});

	it(@"should take and terminate from an infinite stream", ^{
	verifyValues([infiniteStream take:0], @[]);
	verifyValues([infiniteStream take:1], @[ RACUnit.defaultUnit ]);
	verifyValues([infiniteStream take:2], @[ RACUnit.defaultUnit, RACUnit.defaultUnit ]);
	});

	it(@"should take and terminate from a single-item stream", ^{
	NSArray *values = @[ RACUnit.defaultUnit ];
	RACStream *stream = streamWithValues(values);
	verifyValues([stream take:1], values);
	});
	});

	describe(@"zip stream creation methods", ^{
	__block NSArray *valuesOne;

	__block RACStream *streamOne;
	__block RACStream *streamTwo;
	__block RACStream *streamThree;
	__block NSArray *threeStreams;

	__block NSArray *oneStreamTuples;
	__block NSArray *twoStreamTuples;
	__block NSArray *threeStreamTuples;

	before(^{
	valuesOne = @[ @"Ada", @"Bob", @"Dea" ];
	NSArray *valuesTwo = @[ @"eats", @"cooks", @"jumps" ];
	NSArray *valuesThree = @[ @"fish", @"bear", @"rock" ];

	streamOne = streamWithValues(valuesOne);
	streamTwo = streamWithValues(valuesTwo);
	streamThree = streamWithValues(valuesThree);
	threeStreams = @[ streamOne, streamTwo, streamThree ];

	oneStreamTuples = @[
	RACTuplePack(valuesOne[0]),
	RACTuplePack(valuesOne[1]),
	RACTuplePack(valuesOne[2]),
	];

	twoStreamTuples = @[
	RACTuplePack(valuesOne[0], valuesTwo[0]),
	RACTuplePack(valuesOne[1], valuesTwo[1]),
	RACTuplePack(valuesOne[2], valuesTwo[2]),
	];

	threeStreamTuples = @[
	RACTuplePack(valuesOne[0], valuesTwo[0], valuesThree[0]),
	RACTuplePack(valuesOne[1], valuesTwo[1], valuesThree[1]),
	RACTuplePack(valuesOne[2], valuesTwo[2], valuesThree[2]),
	];
	});

	describe(@"-zipWith:", ^{
	it(@"should make a stream of tuples", ^{
	RACStream *stream = [streamOne zipWith:streamTwo];
	verifyValues(stream, twoStreamTuples);
	});

	it(@"should truncate streams", ^{
	RACStream *shortStream = streamWithValues(@[ @"now", @"later" ]);
	RACStream *stream = [streamOne zipWith:shortStream];

	verifyValues(stream, @[
	RACTuplePack(valuesOne[0], @"now"),
	RACTuplePack(valuesOne[1], @"later")
	]);
	});

	it(@"should work on infinite streams", ^{
	RACStream *stream = [streamOne zipWith:infiniteStream];
	verifyValues(stream, @[
	RACTuplePack(valuesOne[0], RACUnit.defaultUnit),
	RACTuplePack(valuesOne[1], RACUnit.defaultUnit),
	RACTuplePack(valuesOne[2], RACUnit.defaultUnit)
	]);
	});

	it(@"should handle multiples of the same stream", ^{
	RACStream *stream = [streamOne zipWith:streamOne];
	verifyValues(stream, @[
	RACTuplePack(valuesOne[0], valuesOne[0]),
	RACTuplePack(valuesOne[1], valuesOne[1]),
	RACTuplePack(valuesOne[2], valuesOne[2]),
	]);
	});
	});

	describe(@"+zip:reduce:", ^{
	it(@"should reduce values", ^{
	RACStream stream = [streamClass zip:threeStreams reduce:^ NSString (id x, id y, id z) {
	return [NSString stringWithFormat:@"%@ %@ %@", x, y, z];
	}];
	verifyValues(stream, @[ @"Ada eats fish", @"Bob cooks bear", @"Dea jumps rock" ]);
	});

	it(@"should truncate streams", ^{
	RACStream *shortStream = streamWithValues(@[ @"now", @"later" ]);
	NSArray *streams = [threeStreams arrayByAddingObject:shortStream];
	RACStream stream = [streamClass zip:streams reduce:^ NSString (id w, id x, id y, id z) {
	return [NSString stringWithFormat:@"%@ %@ %@ %@", w, x, y, z];
	}];
	verifyValues(stream, @[ @"Ada eats fish now", @"Bob cooks bear later" ]);
	});

	it(@"should work on infinite streams", ^{
	NSArray *streams = [threeStreams arrayByAddingObject:infiniteStream];
	RACStream stream = [streamClass zip:streams reduce:^ NSString (id w, id x, id y, id z) {
	return [NSString stringWithFormat:@"%@ %@ %@", w, x, y];
	}];
	verifyValues(stream, @[ @"Ada eats fish", @"Bob cooks bear", @"Dea jumps rock" ]);
	});

	it(@"should handle multiples of the same stream", ^{
	NSArray *streams = @[ streamOne, streamOne, streamTwo, streamThree, streamTwo, streamThree ];
	RACStream stream = [streamClass zip:streams reduce:^ NSString (id x1, id x2, id y1, id z1, id y2, id z2) {
	return [NSString stringWithFormat:@"%@ %@ %@ %@ %@ %@", x1, x2, y1, z1, y2, z2];
	}];
	verifyValues(stream, @[ @"Ada Ada eats fish eats fish", @"Bob Bob cooks bear cooks bear", @"Dea Dea jumps rock jumps rock" ]);
	});
	});

	describe(@"+zip:", ^{
	it(@"should make a stream of tuples out of single value", ^{
	RACStream *stream = [streamClass zip:@[ streamOne ]];
	verifyValues(stream, oneStreamTuples);
	});

	it(@"should make a stream of tuples out of an array of streams", ^{
	RACStream *stream = [streamClass zip:threeStreams];
	verifyValues(stream, threeStreamTuples);
	});

	it(@"should make an empty stream if given an empty array", ^{
	RACStream *stream = [streamClass zip:@[]];
	verifyValues(stream, @[]);
	});

	it(@"should make a stream of tuples out of an enumerator of streams", ^{
	RACStream *stream = [streamClass zip:threeStreams.objectEnumerator];
	verifyValues(stream, threeStreamTuples);
	});

	it(@"should make an empty stream if given an empty enumerator", ^{
	RACStream *stream = [streamClass zip:@[].objectEnumerator];
	verifyValues(stream, @[]);
	});
	});
	});

	describe(@"+concat:", ^{
	__block NSArray *streams = nil;
	__block NSArray *result = nil;

	before(^{
	RACStream *a = [streamClass return:@0];
	RACStream *b = [streamClass empty];
	RACStream *c = streamWithValues(@[ @1, @2, @3 ]);
	RACStream *d = [streamClass return:@4];
	RACStream *e = [streamClass return:@5];
	RACStream *f = [streamClass empty];
	RACStream *g = [streamClass empty];
	RACStream *h = streamWithValues(@[ @6, @7 ]);
	streams = @[ a, b, c, d, e, f, g, h ];
	result = @[ @0, @1, @2, @3, @4, @5, @6, @7 ];
	});

	it(@"should concatenate an array of streams", ^{
	RACStream *stream = [streamClass concat:streams];
	verifyValues(stream, result);
	});

	it(@"should concatenate an enumerator of streams", ^{
	RACStream *stream = [streamClass concat:streams.objectEnumerator];
	verifyValues(stream, result);
	});
	});

	it(@"should scan", ^{
	RACStream *stream = streamWithValues(@[ @1, @2, @3, @4 ]);
	RACStream scanned = [stream scanWithStart:@0 reduce:^(NSNumber running, NSNumber *next) {
	return @(running.integerValue + next.integerValue);
	}];

	verifyValues(scanned, @[ @1, @3, @6, @10 ]);
	});

	describe(@"taking with a predicate", ^{
	NSArray *values = @[ @0, @1, @2, @3, @0, @2, @4 ];

	__block RACStream *stream;

	before(^{
	stream = streamWithValues(values);
	});

	it(@"should take until a predicate is true", ^{
	RACStream taken = [stream takeUntilBlock:^ BOOL (NSNumber x) {
	return x.integerValue >= 3;
	}];

	verifyValues(taken, @[ @0, @1, @2 ]);
	});

	it(@"should take while a predicate is true", ^{
	RACStream taken = [stream takeWhileBlock:^ BOOL (NSNumber x) {
	return x.integerValue <= 1;
	}];

	verifyValues(taken, @[ @0, @1 ]);
	});

	it(@"should take a full stream", ^{
	RACStream taken = [stream takeWhileBlock:^ BOOL (NSNumber x) {
	return x.integerValue <= 10;
	}];

	verifyValues(taken, values);
	});

	it(@"should return an empty stream", ^{
	RACStream taken = [stream takeWhileBlock:^ BOOL (NSNumber x) {
	return x.integerValue < 0;
	}];

	verifyValues(taken, @[]);
	});

	it(@"should terminate an infinite stream", ^{
	RACStream infiniteCounter = [infiniteStream scanWithStart:@0 reduce:^(NSNumber running, id _) {
	return @(running.unsignedIntegerValue + 1);
	}];

	RACStream taken = [infiniteCounter takeWhileBlock:^ BOOL (NSNumber x) {
	return x.integerValue <= 5;
	}];

	verifyValues(taken, @[ @1, @2, @3, @4, @5 ]);
	});
	});

	describe(@"skipping with a predicate", ^{
	NSArray *values = @[ @0, @1, @2, @3, @0, @2, @4 ];

	__block RACStream *stream;

	before(^{
	stream = streamWithValues(values);
	});

	it(@"should skip until a predicate is true", ^{
	RACStream taken = [stream skipUntilBlock:^ BOOL (NSNumber x) {
	return x.integerValue >= 3;
	}];

	verifyValues(taken, @[ @3, @0, @2, @4 ]);
	});

	it(@"should skip while a predicate is true", ^{
	RACStream taken = [stream skipWhileBlock:^ BOOL (NSNumber x) {
	return x.integerValue <= 1;
	}];

	verifyValues(taken, @[ @2, @3, @0, @2, @4 ]);
	});

	it(@"should skip a full stream", ^{
	RACStream taken = [stream skipWhileBlock:^ BOOL (NSNumber x) {
	return x.integerValue <= 10;
	}];

	verifyValues(taken, @[]);
	});

	it(@"should finish skipping immediately", ^{
	RACStream taken = [stream skipWhileBlock:^ BOOL (NSNumber x) {
	return x.integerValue < 0;
	}];

	verifyValues(taken, values);
	});
	});

	describe(@"-combinePreviousWithStart:reduce:", ^{
	NSArray *values = @[ @1, @2, @3 ];
	__block RACStream *stream;
	beforeEach(^{
	stream = streamWithValues(values);
	});

	it(@"should pass the previous next into the reduce block", ^{
	NSMutableArray *previouses = [NSMutableArray array];
	RACStream *mapped = [stream combinePreviousWithStart:nil reduce:^(id previous, id next) {
	[previouses addObject:previous ?: RACTupleNil.tupleNil];
	return next;
	}];

	verifyValues(mapped, @[ @1, @2, @3 ]);

	NSArray *expected = @[ RACTupleNil.tupleNil, @1, @2 ];
	expect(previouses).to.equal(expected);
	});

	it(@"should send the combined value", ^{
	RACStream mapped = [stream combinePreviousWithStart:@1 reduce:^(NSNumber previous, NSNumber *next) {
	return [NSString stringWithFormat:@"%lu - %lu", (unsigned long)previous.unsignedIntegerValue, (unsigned long)next.unsignedIntegerValue];
	}];

	verifyValues(mapped, @[ @"1 - 1", @"1 - 2", @"2 - 3" ]);
	});
	});

	it(@"should reduce tuples", ^{
	RACStream *stream = streamWithValues(@[
	RACTuplePack(@"foo", @"bar"),
	RACTuplePack(@"buzz", @"baz"),
	RACTuplePack(@"", @"_")
	]);

	RACStream reduced = [stream reduceEach:^(NSString a, NSString *b) {
	return [a stringByAppendingString:b];
	}];

	verifyValues(reduced, @[ @"foobar", @"buzzbaz", @"_" ]);
	});
	});

	SharedExampleGroupsEnd