5 files changed, 82 insertions, 1 deletions
diff --git a/Framework/MASDictionaryTransformer.h b/Framework/MASDictionaryTransformer.h
new file mode 100644
index 0000000..94c5bc9
--- /dev/null
+++ b/Framework/MASDictionaryTransformer.h
@@ -0,0 +1,2 @@
+@interface MASDictionaryTransformer : NSValueTransformer
+@end
diff --git a/Framework/MASDictionaryTransformer.m b/Framework/MASDictionaryTransformer.m
new file mode 100644
index 0000000..f0d9b2e
--- /dev/null
+++ b/Framework/MASDictionaryTransformer.m
@@ -0,0 +1,42 @@
+#import "MASDictionaryTransformer.h"
+#import "MASShortcut.h"
+
+static NSString *const MASKeyCodeKey = @"keyCode";
+static NSString *const MASModifierFlagsKey = @"modifierFlags";
+
+@implementation MASDictionaryTransformer
+
++ (BOOL) allowsReverseTransformation
+{
+    return YES;
+}
+
+- (NSDictionary*) reverseTransformedValue: (MASShortcut*) shortcut
+{
+    return @{
+        MASKeyCodeKey: @([shortcut keyCode]),
+        MASModifierFlagsKey: @([shortcut modifierFlags])
+    };
+}
+
+- (MASShortcut*) transformedValue: (NSDictionary*) dictionary
+{
+    // We have to be defensive here as the value may come from user defaults.
+    if (![dictionary isKindOfClass:[NSDictionary class]]) {
+        return nil;
+    }
+
+    id keyCodeBox = [dictionary objectForKey:MASKeyCodeKey];
+    id modifierFlagsBox = [dictionary objectForKey:MASModifierFlagsKey];
+
+    SEL integerValue = @selector(integerValue);
+    if (![keyCodeBox respondsToSelector:integerValue] || ![modifierFlagsBox respondsToSelector:integerValue]) {
+        return nil;
+    }
+
+    return [MASShortcut
+        shortcutWithKeyCode:[keyCodeBox integerValue]
+        modifierFlags:[modifierFlagsBox integerValue]];
+}
+
+@end
diff --git a/Framework/MASDictionaryTransformerTests.m b/Framework/MASDictionaryTransformerTests.m
new file mode 100644
index 0000000..78dfa25
--- /dev/null
+++ b/Framework/MASDictionaryTransformerTests.m
@@ -0,0 +1,25 @@
+#import "Shortcut.h"
+
+@interface MASDictionaryTransformerTests : XCTestCase
+@end
+
+@implementation MASDictionaryTransformerTests
+
+- (void) testErrorHandling
+{
+    MASDictionaryTransformer *transformer = [MASDictionaryTransformer new];
+    XCTAssertNil([transformer transformedValue:nil],
+        @"Decoding a shortcut from a nil dictionary returns nil.");
+    XCTAssertNil([transformer transformedValue:(id)@"foo"],
+        @"Decoding a shortcut from a invalid-type dictionary returns nil.");
+    XCTAssertNil([transformer transformedValue:@{}],
+        @"Decoding a shortcut from an empty dictionary returns nil.");
+    XCTAssertNil([transformer transformedValue:@{@"keyCode":@"foo"}],
+        @"Decoding a shortcut from a wrong-typed dictionary returns nil.");
+    XCTAssertNil([transformer transformedValue:@{@"keyCode":@1}],
+        @"Decoding a shortcut from an incomplete dictionary returns nil.");
+    XCTAssertNil([transformer transformedValue:@{@"modifierFlags":@1}],
+        @"Decoding a shortcut from an incomplete dictionary returns nil.");
+}
+
+@end
diff --git a/Framework/MASShortcutBinderTests.m b/Framework/MASShortcutBinderTests.m
index 9259e9d..199eb2f 100644
--- a/Framework/MASShortcutBinderTests.m
+++ b/Framework/MASShortcutBinderTests.m
@@ -1,4 +1,4 @@
-#import "MASShortcutBinder.h"
+#import "Shortcut.h"
 
 static NSString *const SampleDefaultsKey = @"sampleShortcut";
 
@@ -77,4 +77,15 @@ static NSString *const SampleDefaultsKey = @"sampleShortcut";
         @"Bind after unbinding.");
 }
 
+- (void) testTransformerDeserialization
+{
+    MASShortcut *shortcut = [MASShortcut shortcutWithKeyCode:5 modifierFlags:1048576];
+    NSDictionary *storedShortcut = @{@"keyCode": @5, @"modifierFlags": @1048576};
+    [_defaults setObject:storedShortcut forKey:SampleDefaultsKey];
+    [_binder setBindingOptions:@{NSValueTransformerBindingOption:[MASDictionaryTransformer new]}];
+    [_binder bindShortcutWithDefaultsKey:SampleDefaultsKey toAction:^{}];
+    XCTAssertTrue([_monitor isShortcutRegistered:shortcut],
+        @"Deserialize shortcut from user defaults using a custom transformer.");
+}
+
 @end
diff --git a/Framework/Shortcut.h b/Framework/Shortcut.h
index dce07a5..df33f17 100644
--- a/Framework/Shortcut.h
+++ b/Framework/Shortcut.h
@@ -2,4 +2,5 @@
 #import "MASShortcutValidator.h"
 #import "MASShortcutMonitor.h"
 #import "MASShortcutBinder.h"
+#import "MASDictionaryTransformer.h"
 #import "MASShortcutView.h"