Being The Boss.

21-01-13

I've got a module this semester where in, we're to work as small games companies. It's straight forward enough, the class of 30ish students has been split into two teams of ten and we're using the Cry engine and Scrum to create one prototype game each. The game has to be a FPS zombie killing game, multiplayer optional.

Now, in that we're supposed be working as a games company we were all to be given roles based on skills and personal preference. These roles were to be given out by the company producer, an elected executive type role, basically the producer is the guy in charge. This role has real power in the module, they manage the team, make all the final decisions about the game and if necessary, discipline team members. The producer can actually have members of his team kicked off the module if it's deemed necessary.

I'd put my name in for producer. Thinking that, if I got it, it would be good experience relating to my plans after graduation, I also thought it would be nice if I was actually put in charge of a project by my peers instead of just assuming the role.

The campaign was short, we stood in front of the class and presented our fitness for candidacy for 2 minutes each. I'm not well known at the university and I don't even think I'm well liked, I have a habit of winding up total strangers and openly mocking design students, many of whom were on that module. I screwed up my 'speech' delivery pretty royally and made myself look a real idiot. But when the votes came in I (having snuck a peek at the count) was on top... oh... goodie.

So now, here I am leading one of three teams in making a game from the ground up. We're using a commercial grade engine so it's not nearly as much work as it sounds, but there's still an awful lot to do, especially for me. I've got 10 other students relying on me to get a good grade in this module, I've got to manage their time, their tasks and the quality of their work. I've got to organise and lead regular meetings, orchestrate documentation and be held accountable for any and all the problems. I've also got to track it all and report on it. I have a lead artist, designer, tools developer, scripter and 6 team members assigned to various areas. In all I have 2 game designers and 8+ programmers, I'm still waiting for a couple a stragglers to be assigned to my team. All looking to me for decisive guidance and support...

What have I gotten myself in to?

My First TDD Kata - Objective C - Xcode 4.5 - OCUnit - ARC

Ok, so I've taken the entire day to work on a programming Kata using TDD.

I started with the same exercise that I was given during an interview for an industrial placement a few weeks ago http://codekata.pragprog.com/2007/01/code_kata_one_s.html just so that I had an idea of where to start.

This code has taken me all day but for good reason.
Firstly I've never used TDD before, nor do I have any idea of how to use OCUnit. I have quite limited experience in programming generally so this was all a bit of a learning curve for me.
Secondly, this paradigm is basically the opposite of the way in which I've learned to program. I find it very, very difficult to think this way.

I'm actually quite pleased with the result. As applications go it's functional, seems robust and the design isn't far off from what I would have designed otherwise. It will be interesting to come back to this Kata later and see what differences there are.

What did I learn?

TDD is a concept, I could hear the criticisms screaming out at me as I did it but once I got going it actually started to come really naturally.

Two problems.
From time to time a tricky change comes up. For example in my application I made the decision to change from scanning in Strings to scanning in item objects. Looking back now I can see how I maybe could have handled this differently and maybe made things a little bit easier on myself. But still there was a lot of time spend pondering this, while outside of TDD the change would have been a no-brainer, just change an argument here and a return type there an done. TDD meant that I wound up writing a whole new function for it to save failing the older tests. I'm hoping that some more practice in TDD will help me to handle this type of situation in the future.

There was a real sense of fragility when programming. When implementing the BOGOF feature I found myself tip-toeing around the code trying to change as little as possible as not to fail my older tests, again I hope that experience will take care of this but I'm not so sure.

The design comes from the refactoring stage really. Refactoring seems to be the time to do a little bit of 'Crystal Balling' a little bit and try to introduce some good code and design practices.

Oh and if you're wondering about the weird way I've worked with NSNumber, well I can't really explain myself, I just had a really hard time with it and the primitives. I may do my next kata in a different language.

My Code.
Tests

 -(void)testCheckOut {  
   NSNumber *expected = [NSNumber numberWithDouble:0.0];  
   NSNumber *result = [scanner checkOut];  
   STAssertEquals([expected doubleValue], [result doubleValue], @"Expected %g, but returned %g", [expected doubleValue], [result doubleValue]);  
 }  
 -(void)testScanItem {  
   NSNumber *expected = [NSNumber numberWithDouble:0.60];  
   [scanner scanItem:(@"apple")];  
   NSNumber *result = [scanner checkOut];  
   STAssertEquals([expected doubleValue], [result doubleValue], @"Expected %g, but returned %g", [expected doubleValue], [result doubleValue]);  
 }  
 -(void)testScanningTwoItems {  
   NSNumber *expected = [NSNumber numberWithDouble:1.20];  
   [scanner scanItem:(@"apple")];  
   [scanner scanItem:(@"apple")];  
   NSNumber *result = [scanner checkOut];  
   STAssertEquals([expected doubleValue], [result doubleValue], @"Expected %g, but returned %g", [expected doubleValue], [result doubleValue]);  
 }  
 -(void)testScanningAnItemWithADifferentPrice{  
   double expected = 0.7;  
   [scanner scanItem:@"banana"];  
   double result = [[scanner checkOut] doubleValue];  
   STAssertEquals(expected, result, @"Expected %g, but returned %g", expected, result);  
 }  
 -(void)testScanningTwoItemsWithDifferentPrices {  
   double expected = 0.7+0.6;  
   [scanner scanItem:@"apple"];  
   [scanner scanItem:@"banana"];  
   double result = [[scanner checkOut] doubleValue];  
   STAssertEquals(expected, result, @"Expected %g, but returned %g", expected, result);  
 }  
 -(void)testScanningMultipleItemsObjectsOfVaryingPrice {  
   Item* apple = [[Item alloc] initWithDescription:@"apple" andPrice:[NSNumber numberWithDouble:0.6]];  
   Item* banana = [[Item alloc] initWithDescription:@"banana" andPrice:[NSNumber numberWithDouble:0.7]];  
   Item* orange = [[Item alloc] initWithDescription:@"orange" andPrice:[NSNumber numberWithDouble:0.5]];  
   double expected = 0.0;  
   [scanner scanItem:apple.description];  
   expected += [apple.price doubleValue];  
   [scanner scanItem:banana.description];  
   expected += [banana.price doubleValue];  
   [scanner scanItem:orange.description];  
   expected += [orange.price doubleValue];  
   [scanner scanItem:apple.description];  
   expected += [apple.price doubleValue];  
   double result = [[scanner checkOut] doubleValue];  
   STAssertEquals(expected, result, @"Expected %g, but returned %g", expected, result);  
 }  
 -(void)testScanningItemAsObject {  
   Item* apple = [[Item alloc] initWithDescription:@"apple" andPrice:[NSNumber numberWithDouble:0.6]];  
   double expected = 0.6;  
   [scanner scanObject:apple];  
   double result = [[scanner checkOut] doubleValue];  
   STAssertEquals(expected, result, @"Expected %g, but returned %g", expected, result);  
 }  
 -(void)testScanningMultipleObjects {  
   Item* apple = [[Item alloc] initWithDescription:@"apple" andPrice:[NSNumber numberWithDouble:0.6]];  
   Item* banana = [[Item alloc] initWithDescription:@"banana" andPrice:[NSNumber numberWithDouble:0.7]];  
   double expected = apple.price.doubleValue + banana.price.doubleValue;  
   [scanner scanObject:apple];  
   [scanner scanObject:banana];  
   double result = [[scanner checkOut] doubleValue];  
   STAssertEquals(expected, result, @"Expected %g, but returned %g", expected, result);  
 }  
 -(void)testBOGOFWithTwoOfTheSameItem {  
   Item* apple = [[Item alloc] initWithDescription:@"apple" andPrice:[NSNumber numberWithDouble:0.6]];  
   double expected = apple.price.doubleValue;  
   [scanner scanObject:apple];  
   [scanner scanObject:apple];  
   double result = [[scanner checkOut] doubleValue];  
   STAssertEquals(expected, result, @"Expected %g, but returned %g", expected, result);  
 }  
 -(void)testBOGOFWithMultipleVaryingItems {  
   Item* apple = [[Item alloc] initWithDescription:@"apple" andPrice:[NSNumber numberWithDouble:0.6]];  
   Item* banana = [[Item alloc] initWithDescription:@"banana" andPrice:[NSNumber numberWithDouble:0.7]];  
   double expected = 0.0;  
   [scanner scanObject:apple];  
   expected += apple.price.doubleValue;  
   [scanner scanObject:apple];  
   [scanner scanObject:banana];  
   expected += banana.price.doubleValue;  
   [scanner scanObject:banana];  
   [scanner scanObject:banana];  
   expected += banana.price.doubleValue;  
   double result = [[scanner checkOut] doubleValue];  
   STAssertEquals(expected, result, @"Expected %g, but returned %g", expected, result);  
 }  

Application

 -(PriceScanner*)init {  
   self.total = [NSNumber numberWithDouble:0.0];  
   self.list = [[NSMutableArray alloc] init];  
   return self;  
 }  
 -(void)scanObject:(Item*)item {  
   [self.list addObject:item];  
 }  
 -(void)scanItem:(NSString*)item {  
   if ([item isEqualToString:@"apple"]){  
     self.total = [NSNumber numberWithDouble:[self.total doubleValue] + 0.6];  
   }  
   if ([item isEqualToString:@"banana"]){  
     self.total = [NSNumber numberWithDouble:[self.total doubleValue] + 0.7];  
   }  
   if ([item isEqualToString:@"orange"]){  
     self.total = [NSNumber numberWithDouble:[self.total doubleValue] + 0.5];  
   }  
 }  
 -(void)applyBOGOF{  
   double newTotal = [self.total doubleValue];  
   NSMutableSet *tempSet = [[NSMutableSet alloc] init];  
   for (Item* i in self.list){  
     if ([tempSet containsObject:i.description]){  
       newTotal -= [i.price doubleValue];  
       [tempSet removeObject:i.description];  
     } else {  
       [tempSet addObject:i.description];  
     }  
   }  
   self.total = [NSNumber numberWithDouble:newTotal];  
 }  
 -(NSNumber*)checkOut {  
   double newTotal = [self.total doubleValue];  
   for (Item* i in self.list){  
     newTotal += i.price.doubleValue;  
   }  
   self.total = [NSNumber numberWithDouble:newTotal];  
   [self applyBOGOF];  
   return self.total;  
 }