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A Matcher Framework for Objective-C/Cocoa

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README.md

Expecta

A Matcher Framework for Objective-C/Cocoa

NOTICE

Expecta 0.3.x removes support for Garbage Collected targets, as support for these has been removed from Xcode 5.1 and greater. If you need Garbage Collection support, please continue to use Expecta 0.2.4. The minimum deployment targets have also been raised to iOS 5.x and OS X 10.7 or greater.

Expecta 0.2.x and later has a new syntax that is slightly different from Expecta 0.1.x. For example expect(x).toEqual(y) should now be written as expect(x).to.equal(y). You can do #define EXP_OLD_SYNTAX before importing Expecta.h to enable backward-compatiblity mode, but keep in mind that the old syntax is deprecated.

INTRODUCTION

The main advantage of using Expecta over other matcher frameworks is that you do not have to specify the data types. Also, the syntax of Expecta matchers is much more readable and does not suffer from parenthesitis.

OCHamcrest

assertThat(@"foo", is(equalTo(@"foo")));
assertThatUnsignedInteger(foo, isNot(equalToUnsignedInteger(1)));
assertThatBool([bar isBar], is(equalToBool(YES)));
assertThatDouble(baz, is(equalToDouble(3.14159)));

vs. Expecta

expect(@"foo").to.equal(@"foo"); // `to` is a syntatic sugar and can be safely omitted.
expect(foo).notTo.equal(1);
expect([bar isBar]).to.equal(YES);
expect(baz).to.equal(3.14159);

SETUP

Use CocoaPods

target :MyApp do
#your app dependencies
end

target :MyAppTests do
  pod 'Expecta',     '~> 0.2.4'   # expecta matchers
#pod 'Specta', '~> 0.1.11' #specta bdd framework
end

or

  1. Clone from Github.
  2. Run rake in project root to build.
  3. Copy and add all header files in products folder to the Spec/Test target in your Xcode project.
  4. For OS X projects, copy and add libExpecta-macosx.a in products folder to the Spec/Test target in your Xcode project. For iOS projects, copy and add libExpecta-ios-universal.a in products folder to the Spec/Test target in your Xcode project.
  5. Add -ObjC to the "Other Linker Flags" build setting for the Spec/Test target in your Xcode project.
  6. Add the following to your test code.
// #define EXP_OLD_SYNTAX // enable backward-compatibility
#define EXP_SHORTHAND
#import "Expecta.h"

If EXP_SHORTHAND is not defined, expectations must be written with EXP_expect instead of expect.

Expecta is framework-agnostic. It works well with XCTest, OCUnit (SenTestingKit) and OCUnit-compatible test frameworks such as Specta, GHUnit and GTMUnit. Expecta also supports Cedar.

BUILT-IN MATCHERS

expect(x).to.equal(y); compares objects or primitives x and y and passes if they are identical (==) or equivalent (isEqual:).

expect(x).to.beIdenticalTo(y); compares objects x and y and passes if they are identical and have the same memory address.

expect(x).to.beNil(); passes if x is nil.

expect(x).to.beTruthy(); passes if x evaluates to true (non-zero).

expect(x).to.beFalsy(); passes if x evaluates to false (zero).

expect(x).to.contain(y); passes if an instance of NSArray or NSString x contains y.

expect(x).to.beSupersetOf(y); passes if an instance of NSArray, NSSet, NSDictionary or NSOrderedSet x contains all elements of y.

expect(x).to.haveCountOf(y); passes if an instance of NSArray, NSSet, NSDictionary or NSString x has a count or length of y.

expect(x).to.beEmpty(); passes if an instance of NSArray, NSSet, NSDictionary or NSString x has a count or length of 0.

expect(x).to.beInstanceOf([Foo class]); passes if x is an instance of a class Foo.

expect(x).to.beKindOf([Foo class]); passes if x is an instance of a class Foo or if x is an instance of any class that inherits from the class Foo.

expect([Foo class]).to.beSubclassOf([Bar class]); passes if the class Foo is a subclass of the class Bar or if it is identical to the class Bar. Use beKindOf() for class clusters.

expect(x).to.beLessThan(y); passes if x is less than y.

expect(x).to.beLessThanOrEqualTo(y); passes if x is less than or equal to y.

expect(x).to.beGreaterThan(y); passes if x is greater than y.

expect(x).to.beGreaterThanOrEqualTo(y); passes if x is greater than or equal to y.

expect(x).to.beInTheRangeOf(y,z); passes if x is in the range of y and z.

expect(x).to.beCloseTo(y); passes if x is close to y.

expect(x).to.beCloseToWithin(y, z); passes if x is close to y within z.

expect(^{ /* code */ }).to.raise(@"ExceptionName"); passes if a given block of code raises an exception named ExceptionName.

expect(^{ /* code */ }).to.raiseAny(); passes if a given block of code raises any exception.

expect(x).to.conformTo(y); passes if x conforms to the protocol y.

expect(x).to.respondTo(y); passes if x responds to the selector y.

expect(^{ /* code */ }).to.notify(@"NotificationName"); passes if a given block of code generates an NSNotification named NotificationName.

expect(^{ /* code */ }).to.notify(notification); passes if a given block of code generates an NSNotification equal to the passed notification.

expect(x).to.beginWith(y); passes if an instance of NSString, NSArray, or NSOrderedSet x begins with y. Also aliased by startWith

expect(x).to.endWith(y); passes if an instance of NSString, NSArray, or NSOrderedSet x ends with y.

Please contribute more matchers.

INVERTING MATCHERS

Every matcher's criteria can be inverted by prepending .notTo or .toNot:

expect(x).notTo.equal(y); compares objects or primitives x and y and passes if they are not equivalent.

ASYNCHRONOUS TESTING

Every matcher can be made to perform asynchronous testing by prepending .will or .willNot:

expect(x).will.beNil(); passes if x becomes nil before the timeout.

expect(x).willNot.beNil(); passes if x becomes non-nil before the timeout.

Default timeout is 1.0 second. This setting can be changed by calling [Expecta setAsynchronousTestTimeout:x], where x is the desired timeout.

WRITING NEW MATCHERS

Writing a new matcher is easy with special macros provided by Expecta. Take a look at how .beKindOf() matcher is defined:

EXPMatchers+beKindOf.h

#import "Expecta.h"

EXPMatcherInterface(beKindOf, (Class expected));
// 1st argument is the name of the matcher function
// 2nd argument is the list of arguments that may be passed in the function
// call.
// Multiple arguments are fine. (e.g. (int foo, float bar))

#define beAKindOf beKindOf

EXPMatchers+beKindOf.m

#import "EXPMatchers+beKindOf.h"

EXPMatcherImplementationBegin(beKindOf, (Class expected)) {
  BOOL actualIsNil = (actual == nil);
  BOOL expectedIsNil = (expected == nil);

  prerequisite(^BOOL {
    return !(actualIsNil || expectedIsNil);
    // Return `NO` if matcher should fail whether or not the result is inverted
    // using `.Not`.
  });

  match(^BOOL {
    return [actual isKindOfClass:expected];
    // Return `YES` if the matcher should pass, `NO` if it should not.
    // The actual value/object is passed as `actual`.
    // Please note that primitive values will be wrapped in NSNumber/NSValue.
  });

  failureMessageForTo(^NSString * {
    if (actualIsNil)
      return @"the actual value is nil/null";
    if (expectedIsNil)
      return @"the expected value is nil/null";
    return [NSString
        stringWithFormat:@"expected: a kind of %@, "
                          "got: an instance of %@, which is not a kind of %@",
                         [expected class], [actual class], [expected class]];
    // Return the message to be displayed when the match function returns `YES`.
  });

  failureMessageForNotTo(^NSString * {
    if (actualIsNil)
      return @"the actual value is nil/null";
    if (expectedIsNil)
      return @"the expected value is nil/null";
    return [NSString
        stringWithFormat:@"expected: not a kind of %@, "
                          "got: an instance of %@, which is a kind of %@",
                         [expected class], [actual class], [expected class]];
    // Return the message to be displayed when the match function returns `NO`.
  });
}
EXPMatcherImplementationEnd

DYNAMIC PREDICATE MATCHERS

It is possible to add predicate matchers by simply defining the matcher interface, with the matcher implementation being handled at runtime by delegating to the predicate method on your object.

For instance, if you have the following class:

@interface LightSwitch : NSObject
@property (nonatomic, assign, getter=isTurnedOn) BOOL turnedOn;
@end

@implementation LightSwitch
@synthesize turnedOn;
@end

The normal way to write an assertion that the switch is turned on would be:

expect([lightSwitch isTurnedOn]).to.beTruthy();

However, if we define a custom predicate matcher:

EXPMatcherInterface(isTurnedOn, (void));

(Note: we haven't defined the matcher implementation, just it's interface)

You can now write your assertion as follows:

expect(lightSwitch).isTurnedOn();

CONTRIBUTION

You can find the public Tracker project here.

CONTRIBUTION GUIDELINES

  • Please use only spaces and indent 2 spaces at a time.
  • Please prefix instance variable names with a single underscore (_).
  • Please prefix custom classes and functions defined in the global scope with EXP.

CREDITS

Expecta is brought to you by Peter Jihoon Kim and the Specta team.

CONTRIBUTORS

LICENSE

Expecta is licensed under the MIT License.

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