BDD with Specta/Expecta

This is a lightning talk I gave at CocoaHeads CGN on June 15.

Transcript

1. with BDD Specta/Expecta
2. Testing is HARD
3. Why?
4. Test ALL the things!
5. @interface AFHTTPRequestOperationManager : NSObject <NSSecureCoding, NSCopying> @property (readonly, nonatomic, strong) NSURL *baseURL; @property (nonatomic, strong) AFHTTPRequestSerializer <AFURLRequestSerialization> * requestSerializer; @property (nonatomic, strong) AFHTTPResponseSerializer <AFURLResponseSerialization> * responseSerializer; @property (nonatomic, strong) NSOperationQueue *operationQueue; @property (nonatomic, assign) BOOL shouldUseCredentialStorage; @property (nonatomic, strong) NSURLCredential *credential; @property (nonatomic, strong) AFSecurityPolicy *securityPolicy; @property (readwrite, nonatomic, strong) AFNetworkReachabilityManager *reachabilityManager; #if OS_OBJECT_HAVE_OBJC_SUPPORT @property (nonatomic, strong) dispatch_queue_t completionQueue; #else @property (nonatomic, assign) dispatch_queue_t completionQueue; #endif
6. Fragile Tests
7. Frustration
8. Agenda 1.What is BDD and what does it solve? 2.What is Specta? 3.What is Expecta?
9. BDD
10. Behaviour Driven Development
11. Not Specifications Tests
12. Behaviour vs Interface
13. Robust Relevant Descriptive
14. Specta
15. DSL
16. describe(@"Class", ^{ before({ // Create states to be tested }); it(@"should do stuff", ^{ // This is an example block. Place your assertions here. }); context(@"groups related specifications", ^{ // ... more specs }); });
17. Expecta
18. Matcher
19. expect(x).to.equal(y); expect(x).to.beTruthy(); expect(x).to.beFalsy(); expect(x).to.haveCountOf(y); expect(x).to.beNil(); expect(x).notTo.beNil();
20. Example
21. Hamming Distance for DNA strands
22. It is found by comparing two DNA strands and counting how many of the nucleotides are different from their equivalent in the other string. GAGCCTACTAACGGGAT CATCGTAATGACGGCCT ^ ^ ^ ^ ^ ^^ The Hamming distance between these two DNA strands is 7.
23. #import <Foundation/Foundation.h> @interface HammingTest : NSObject - (instancetype)initWithDNAStrands:(NSString *)DNAStrand; - (NSInteger)hammingDistanceWithDNAStrands:(NSString *)aDNAStrand; @end
24. #import "HammingTest.h" @interface HammingTest (Internal) - (BOOL)hasSameLengthAs:(NSString *)aDNAStrand; - (BOOL)isDNAStrand:(NSString *)aDNAStrand; @end
25. - (void)setUp { [super setUp]; self.hamming = [[HammingTest alloc] initWithDNAStrands:@"GAGCCTACTAACGGGAT"]; } - (void)testInit { XCTAssertNotNil(self.hamming); } - (void)testHammingDistanceWithSameLength { NSInteger length = [self.hamming hammingDistanceWithDNAStrands:@"CATCGTAATGACGGCCT"]; XCTAssertEqual(length, 7); } - (void)testHammingDistanceWithDifferentLength { NSInteger length = [self.hamming hammingDistanceWithDNAStrands:@"CATCGTAAT"]; XCTAssertEqual(length, NSIntegerMax); }
26. - (void)testSameLengthWithSameStringLength { BOOL same = [self.hamming hasSameLengthAs:@"CATCGTAATGACGGCCT"]; XCTAssertTrue(same == YES); } - (void)testSameLengthWithDifferentStringLength { BOOL same = [self.hamming hasSameLengthAs:@"CATCGTAAT"]; XCTAssertTrue(same == NO); } - (void)testIsNotDNAStrang { BOOL isDNAStrang = [self.hamming isDNAStrand:@"123456789"]; XCTAssertTrue(isDNAStrang == NO); }
27. SpecBegin(HammingTest) describe(@"HammingTest", ^{ __block id hamming; before(^{ hamming = [[HammingTest alloc] initWithDNAStrands:@"GAGCCTACTAACGGGAT"]; }); it(@"should not be nil", ^{ expect(hamming).notTo.beNil(); }); describe(@"-hammingDistanceWithDNAString", ^{ context(@"with DNA strands of same length", ^{[...]}); context(@"with DNA strands of different length", ^{[...]}); }); }); }); SpecEnd
28. context(@"with DNA strand of same length", ^{ it(@"should return the correct distance for different strands", ^{ NSInteger length = [hamming hammingDistanceWithDNAStrands:@"CATCGTAATGACGGCCT"]; expect(length).to.equal(7); }); it(@"should return zero for same strands", ^{ NSInteger length = [hamming hammingDistanceWithDNAStrands:@"GAGCCTACTAACGGGAT"]; expect(length).to.equal(0); }); });
29. context(@"with DNA strands of different length", ^{ __block NSInteger length; before(^{ length = [hamming hammingDistanceWithDNAStrands:@"CATCGTAAT"]; }); it(@"should return NSIntegerMax", ^{ expect(length).to.equal(NSIntegerMax); }); });
30. On failure …
31. Failing tests: -[HammingTestTest testHammingDistanceWithSameLength] -[HammingTestTest testSameLengthWithSameStringLength] ** TEST FAILED **
32. Failing tests: -[HammingTestSpec test_HammingTest__hammingDistanceWithDNAStrand__with_DNA_strand_of_same_length__sh ould_return_the_correct_distance_for_different_strands] -[HammingTestSpec test_HammingTest__hammingDistanceWithDNAStrand__with_DNA_strand_of_same_length__sh ould_return_zero_for_same_strands] ** TEST FAILED **
33. Recap
34. Not Specifications Tests SOLVED
35. Robust Relevant Descriptive SOLVED
36. Trust Frustration SOLVED
37. mkalmes@mkalmes.net Merci