A category to help work with constraints. Basically what I did is created getters methods to help retrieve a specific constraint, for example: a tableview bottom constraint without having to connect IBOutlets. It's still pretty basic with only 4 methods: - bottomConstraint - topConstraint - widthConstraint - heightConstraint

UIView+Constraints.h

//
//  UIView+Constraints.h
//  Calendar
//
//  Created by Marcio Klepacz on 12/3/13.
//  Copyright (c) 2013 Any.DO. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIView (Constraints)

@property (strong, nonatomic, readonly) NSLayoutConstraint *bottomConstraint;
@property (strong, nonatomic, readonly) NSLayoutConstraint *topConstraint;
@property (strong, nonatomic, readonly) NSLayoutConstraint *widthConstraint;
@property (strong, nonatomic, readonly) NSLayoutConstraint *heightConstraint;

@end

UIView+Constraints.m

//
//  UIView+Constraints.m
//  Calendar
//
//  Created by Marcio Klepacz on 12/3/13.
//  Copyright (c) 2013 Any.DO. All rights reserved.
//

#import "UIView+Constraints.h"

@implementation UIView (Constraints)

- (NSLayoutConstraint *) bottomConstraint
{
    if ([self superviewHasConstraints:self.superview.constraints]) {
        for (NSLayoutConstraint *constraint in self.superview.constraints) {
            if (constraint.firstAttribute == NSLayoutAttributeBottom) {
                return constraint;
            }
        };
    }
    return nil;
}

- (NSLayoutConstraint *) topConstraint
{
    if ([self superviewHasConstraints:self.superview.constraints]) {
        for (NSLayoutConstraint *constraint in self.superview.constraints) {
            if (constraint.firstAttribute == NSLayoutAttributeTop) {
                return constraint;
            }
        };
    }
    return nil;
}

- (NSLayoutConstraint *) widthConstraint
{
    if ([self superviewHasConstraints:self.constraints]) {
        for (NSLayoutConstraint *constraint in self.constraints) {
            if (constraint.firstAttribute == NSLayoutAttributeWidth) {
                return constraint;
            }
        };
    }
    return nil;
}

- (NSLayoutConstraint *) heightConstraint
{
    if ([self superviewHasConstraints:self.constraints]) {
        for (NSLayoutConstraint *constraint in self.constraints) {
            if (constraint.firstAttribute == NSLayoutAttributeHeight) {
                return constraint;
            }
        };
    }
    return nil;
}



#pragma mark -
#pragma private methods

- (BOOL) superviewHasConstraints:(NSArray *)superViewConstraints
{
    if (superViewConstraints == nil || [superViewConstraints count] == 0)
        return NO;
    else
        return YES;
}

@end

UIView+ConstraintsTests.m

#import "UIView+Constraints.h"

// Test support
#import "UIView+ConstraintsPrivateDeclarations.h"
#import <SenTestingKit/SenTestingKit.h>
#import <Kiwi.h>
#import "TestUtils.h"

SPEC_BEGIN(UIViewConstraintsSpecs)

describe(@"UIView+Constraints ", ^{
    __block UIView *sut;
    __block UIView *sutSuperView;
    __block NSLayoutConstraint *constraint;
    
    beforeAll(^{
        sut = [[UIView alloc] init];
        sutSuperView = [[UIView alloc] init];
        [sutSuperView addSubview:sut];
    });
    
    afterAll(^{
        sut = nil;
        sutSuperView = nil;
    });
    
    describe(@"Get bottomConstraint",^{
        
        context(@"When the superview has constraint", ^{
            
            beforeEach(^{
                constraint = [NSLayoutConstraint constraintWithItem:sut.superview
                                                          attribute:NSLayoutAttributeBottom
                                                          relatedBy:NSLayoutRelationEqual
                                                             toItem:sut
                                                          attribute:NSLayoutAttributeTop
                                                         multiplier:1
                                                           constant:1];
                
                [sut.superview addConstraint:constraint];
            });
            
            afterEach(^{
                [sut.superview removeConstraint:constraint];
            });
            
            it(@"should return a bottomConstraint", ^{
                [[sut.bottomConstraint should] equal:constraint];
            });
                
        });
        
        context(@"When don't have constraints", ^{
            
            it(@"should return nil", ^{
                [sut.bottomConstraint shouldBeNil];
            });
        });
        
    });
    
    describe(@"Get topConstraint",^{
        
        context(@"When the superview has constraint", ^{
            
            beforeEach(^{
                constraint = [NSLayoutConstraint constraintWithItem:sut.superview
                                                          attribute:NSLayoutAttributeTop
                                                          relatedBy:NSLayoutRelationEqual
                                                             toItem:sut
                                                          attribute:NSLayoutAttributeBottom
                                                         multiplier:1
                                                           constant:1];
                
                [sut.superview addConstraint:constraint];
            });
            
            afterEach(^{
                [sut.superview removeConstraint:constraint];
            });
            
            it(@"should return a bottomConstraint", ^{
                [[sut.topConstraint should] equal:constraint];
            });
            
        });
        
        context(@"When don't have constraints", ^{
            
            it(@"should return nil", ^{
                [sut.topConstraint shouldBeNil];
            });
        });
        
    });
    
    describe(@"Get widthConstraint",^{
        
        context(@"When the superview has constraint", ^{
            
            beforeEach(^{
                constraint = [NSLayoutConstraint constraintWithItem:sut
                                                          attribute:NSLayoutAttributeWidth
                                                          relatedBy:NSLayoutRelationEqual
                                                             toItem:nil
                                                          attribute:NSLayoutAttributeNotAnAttribute
                                                         multiplier:1
                                                           constant:1];
                
                [sut addConstraint:constraint];
            });
            
            afterEach(^{
                [sut removeConstraint:constraint];
            });
            
            it(@"should return a bottomConstraint", ^{
                [[sut.widthConstraint should] equal:constraint];
            });
            
        });
        
        context(@"When don't have constraints", ^{
            
            it(@"should return nil", ^{
                [sut.widthConstraint shouldBeNil];
            });
        });
        
    });
    
    describe(@"Get heightConstraint",^{
        
        context(@"When the superview has constraint", ^{
            
            beforeEach(^{
                constraint = [NSLayoutConstraint constraintWithItem:sut
                                                          attribute:NSLayoutAttributeHeight
                                                          relatedBy:NSLayoutRelationEqual
                                                             toItem:nil
                                                          attribute:NSLayoutAttributeNotAnAttribute
                                                         multiplier:1
                                                           constant:1];
                
                [sut addConstraint:constraint];
            });
            
            afterEach(^{
                [sut removeConstraint:constraint];
            });
            
            it(@"should return a bottomConstraint", ^{
                [[sut.heightConstraint should] equal:constraint];
            });
            
        });
        
        context(@"When don't have constraints", ^{
            
            it(@"should return nil", ^{
                [sut.heightConstraint shouldBeNil];
            });
        });
        
    });
    
    
});

SPEC_END