Adds JSONHelper methods to read strings. (+1 squashed commit)

Squashed commits:
[30b0a71] Adds JSONHelper methods to read strings.

MonsterCards.xcodeproj/project.pbxproj

@@ -15,6 +15,8 @@
 		E20D032B25031BE500FB6E43 /* LibraryViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = E20D032A25031BE500FB6E43 /* LibraryViewController.m */; };
 		E20D032E25031BEF00FB6E43 /* CollectionsViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = E20D032D25031BEF00FB6E43 /* CollectionsViewController.m */; };
 		E20D033125031BFD00FB6E43 /* DashboardViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = E20D033025031BFD00FB6E43 /* DashboardViewController.m */; };
+		E22F837C2511D14E0072105C /* JSONHelper.m in Sources */ = {isa = PBXBuildFile; fileRef = E22F837B2511D14E0072105C /* JSONHelper.m */; };
+		E22F837F2511E8500072105C /* JSONHelperTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E22F837E2511E8500072105C /* JSONHelperTests.m */; };
 		E2532E8925038DE100CA4CBA /* StringHelper.m in Sources */ = {isa = PBXBuildFile; fileRef = E2532E8825038DE100CA4CBA /* StringHelper.m */; };
 		E2592B8D250D6B8100906A40 /* EditMonsterViewControllerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E2592B8C250D6B8100906A40 /* EditMonsterViewControllerTests.m */; };
 		E25BD5F5250352C4007B04EF /* Monster.m in Sources */ = {isa = PBXBuildFile; fileRef = E25BD5F4250352C4007B04EF /* Monster.m */; };
@@ -82,6 +84,9 @@
 		E20D032D25031BEF00FB6E43 /* CollectionsViewController.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = CollectionsViewController.m; sourceTree = "<group>"; };
 		E20D032F25031BFD00FB6E43 /* DashboardViewController.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = DashboardViewController.h; sourceTree = "<group>"; };
 		E20D033025031BFD00FB6E43 /* DashboardViewController.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = DashboardViewController.m; sourceTree = "<group>"; };
+		E22F837A2511D14E0072105C /* JSONHelper.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = JSONHelper.h; sourceTree = "<group>"; };
+		E22F837B2511D14E0072105C /* JSONHelper.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = JSONHelper.m; sourceTree = "<group>"; };
+		E22F837E2511E8500072105C /* JSONHelperTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = JSONHelperTests.m; sourceTree = "<group>"; };
 		E2532E8725038DE100CA4CBA /* StringHelper.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = StringHelper.h; sourceTree = "<group>"; };
 		E2532E8825038DE100CA4CBA /* StringHelper.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = StringHelper.m; sourceTree = "<group>"; };
 		E2591EB62509DD4900B396FD /* EditableFormFieldDelegate.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = EditableFormFieldDelegate.h; sourceTree = "<group>"; };
@@ -234,6 +239,16 @@
 				E2532E8825038DE100CA4CBA /* StringHelper.m */,
 				E26A73552511BA1900C5677E /* HTMLHelper.h */,
 				E26A73562511BA1900C5677E /* HTMLHelper.m */,
+				E22F837A2511D14E0072105C /* JSONHelper.h */,
+				E22F837B2511D14E0072105C /* JSONHelper.m */,
+			);
+			path = Helpers;
+			sourceTree = "<group>";
+		};
+		E22F837D2511E8350072105C /* Helpers */ = {
+			isa = PBXGroup;
+			children = (
+				E22F837E2511E8500072105C /* JSONHelperTests.m */,
 			);
 			path = Helpers;
 			sourceTree = "<group>";
@@ -302,6 +317,7 @@
 		E2F7249425005E8A007D87ED /* MonsterCardsTests */ = {
 			isa = PBXGroup;
 			children = (
+				E22F837D2511E8350072105C /* Helpers */,
 				E2592B8B250D6B6000906A40 /* Views */,
 				E2FD91E225047C1D00D5E935 /* Models */,
 				E2F7249525005E8A007D87ED /* MonsterCardsTests.m */,
@@ -591,6 +607,7 @@
 				E25BD5FB250369D7007B04EF /* Skill.m in Sources */,
 				E2F7247825005E89007D87ED /* SceneDelegate.m in Sources */,
 				E20D032425031B9D00FB6E43 /* SearchViewController.m in Sources */,
+				E22F837C2511D14E0072105C /* JSONHelper.m in Sources */,
 				E25BD60125036BF8007B04EF /* Language.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -609,6 +626,7 @@
 				E2FD91E425047C4400D5E935 /* AbilityTests.m in Sources */,
 				E2E25805250CC3A7002E7308 /* MonsterCards.xcdatamodeld in Sources */,
 				E2F7249625005E8A007D87ED /* MonsterCardsTests.m in Sources */,
+				E22F837F2511E8500072105C /* JSONHelperTests.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -772,6 +790,7 @@
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = J793L9LQJ2;
+				HEADER_SEARCH_PATHS = "$(SRCROOT)/Pods/**";
 				INFOPLIST_FILE = MonsterCards/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
 				LD_RUNPATH_SEARCH_PATHS = (
@@ -791,6 +810,7 @@
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = J793L9LQJ2;
+				HEADER_SEARCH_PATHS = "$(SRCROOT)/Pods/**";
 				INFOPLIST_FILE = MonsterCards/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
 				LD_RUNPATH_SEARCH_PATHS = (

MonsterCards/Helpers/JSONHelper.h

@@ -0,0 +1,21 @@
+//
+//  JSONHelper.h
+//  MonsterCards
+//
+//  Created by Tom Hicks on 9/15/20.
+//  Copyright © 2020 Tom Hicks. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface JSONHelper : NSObject
+
++(NSString*)readStringFromDictionary:(NSDictionary*)dictionary forKey:(NSString*)key;
++(NSString*)readStringFromDictionary:(NSDictionary*)dictionary forKey:(NSString*)key withDefaultValue:(NSString* _Nullable)defaultValue;
++(NSString*)readStringFromArray:(NSArray*)array forIndex:(NSUInteger)index;
++(NSString*)readStringFromArray:(NSArray*)array forIndex:(NSUInteger)index withDefaultValue:(NSString* _Nullable)defaultValue;
+@end
+
+NS_ASSUME_NONNULL_END

MonsterCards/Helpers/JSONHelper.m

@@ -0,0 +1,39 @@
+//
+//  JSONHelper.m
+//  MonsterCards
+//
+//  Created by Tom Hicks on 9/15/20.
+//  Copyright © 2020 Tom Hicks. All rights reserved.
+//
+
+#import "JSONHelper.h"
+
+@implementation JSONHelper
+
+NSString* coerceObjectToString(NSObject *object, NSString *defaultValue) {
+    if ([object isKindOfClass:[NSString class]]) {
+        return (NSString*)object;
+    }
+
+    return defaultValue;
+}
+
++(NSString*)readStringFromDictionary:(NSDictionary*)dictionary forKey:(NSString*)key {
+    return [JSONHelper readStringFromDictionary:dictionary forKey:key withDefaultValue:nil];
+}
+
++(NSString*)readStringFromDictionary:(NSDictionary*)dictionary forKey:(NSString*)key withDefaultValue:(NSString* _Nullable)defaultValue {
+    NSObject *object = [dictionary objectForKey:key];
+    return coerceObjectToString(object, defaultValue);
+}
+
++(NSString*)readStringFromArray:(NSArray*)array forIndex:(NSUInteger)index{
+    return [JSONHelper readStringFromArray:array forIndex:index withDefaultValue:nil];
+}
+
++(NSString*)readStringFromArray:(NSArray*)array forIndex:(NSUInteger)index withDefaultValue:(NSString* _Nullable)defaultValue {
+    NSObject *object = [array objectAtIndex:index];
+    return coerceObjectToString(object, defaultValue);
+}
+
+@end

MonsterCardsTests/Helpers/JSONHelperTests.m

@@ -0,0 +1,147 @@
+//
+//  JSONHelperTests.m
+//  MonsterCardsTests
+//
+//  Created by Tom Hicks on 9/15/20.
+//  Copyright © 2020 Tom Hicks. All rights reserved.
+//
+
+#import <XCTest/XCTest.h>
+#import "JSONHelper.h"
+
+@interface JSONHelperTests : XCTestCase
+
+@end
+
+@implementation JSONHelperTests {
+    NSString *_jsonStringKey;
+    NSString *_jsonStringValue;
+    NSString *_jsonStringFragment;
+    NSString *_jsonIntegerKey;
+    NSNumber *_jsonIntegerValue;
+    NSString *_jsonIntegerFragment;
+}
+
+NSString* escapeStringForJSON(NSString *unescaped) {
+    return [[unescaped stringByReplacingOccurrencesOfString:@"\\" withString:@"\\\\"] stringByReplacingOccurrencesOfString:@"\"" withString:@"\\\""];
+}
+
+NSDictionary* readJSONDictionaryFromString(NSString *jsonString) {
+    NSData* jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
+    NSDictionary *jsonRoot = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:nil];
+    if (![jsonRoot isKindOfClass:[NSDictionary class]]) {
+        return nil;
+    } else {
+        return jsonRoot;
+    }
+}
+
+NSArray* readJSONArrayFromString(NSString *jsonString) {
+    NSData* jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
+    NSArray *jsonRoot = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:nil];
+    if (![jsonRoot isKindOfClass:[NSArray class]]) {
+        return nil;
+    } else {
+        return jsonRoot;
+    }
+}
+
+- (void)setUp {
+    _jsonStringKey = @"my_string";
+    _jsonStringValue = @"Hello, World!";
+    _jsonStringFragment = [NSString stringWithFormat:@"\"%@\":\"%@\"", escapeStringForJSON(_jsonStringKey), escapeStringForJSON(_jsonStringValue)];
+    _jsonIntegerKey = @"my_int";
+    _jsonIntegerValue = @12345;
+    _jsonIntegerFragment = [NSString stringWithFormat:@"\"%@\":%@", escapeStringForJSON(_jsonIntegerKey), [_jsonIntegerValue stringValue]];
+}
+
+- (void)tearDown {
+}
+
+#pragma mark - Strings in Dictionaries
+
+- (void)testReadStringFromDictionaryReturnsNilIfKeyNotPresent {
+    NSString *jsonString = [NSString stringWithFormat:@"{%@}", _jsonIntegerFragment];
+    NSDictionary *jsonRoot = readJSONDictionaryFromString(jsonString);
+    XCTAssertNotNil(jsonRoot);
+    
+    NSString *readString = [JSONHelper readStringFromDictionary:jsonRoot  forKey:_jsonStringKey];
+    XCTAssertNil(readString);
+}
+
+- (void)testReadStringFromDictionaryWithDefaultReturnsDefaultIfKeyNotPresent {
+    NSString *jsonString = [NSString stringWithFormat:@"{%@}", _jsonIntegerFragment];
+    NSDictionary *jsonRoot = readJSONDictionaryFromString(jsonString);
+    XCTAssertNotNil(jsonRoot);
+    
+    NSString *readString = [JSONHelper readStringFromDictionary:jsonRoot  forKey:_jsonStringKey withDefaultValue:_jsonStringValue];
+    XCTAssertEqualObjects(_jsonStringValue, readString);
+}
+
+- (void) testReadStringFromDictionaryReturnsCorrectValue {
+    NSString *jsonString = [NSString stringWithFormat:@"{%@}", _jsonStringFragment];
+    NSDictionary *jsonRoot = readJSONDictionaryFromString(jsonString);
+    XCTAssertNotNil(jsonRoot);
+    
+    NSString *readString = [JSONHelper readStringFromDictionary:jsonRoot  forKey:_jsonStringKey];
+    XCTAssertEqualObjects(_jsonStringValue, readString);
+}
+
+- (void)testReadStringFromDictionaryWithDefaultReturnsCorrectValue {
+    NSString *jsonString = [NSString stringWithFormat:@"{%@}", _jsonStringFragment];
+    NSDictionary *jsonRoot = readJSONDictionaryFromString(jsonString);
+    XCTAssertNotNil(jsonRoot);
+    
+    NSString *readString = [JSONHelper readStringFromDictionary:jsonRoot  forKey:_jsonStringKey withDefaultValue:@"Some other string"];
+    XCTAssertEqualObjects(_jsonStringValue, readString);
+}
+
+- (void) testReadStringFromDictionaryReturnsNilIfWrongType {
+    NSString *jsonString = [NSString stringWithFormat:@"{\"%@\":%@}", _jsonStringKey, _jsonIntegerValue];
+    NSDictionary *jsonRoot = readJSONDictionaryFromString(jsonString);
+    XCTAssertNotNil(jsonRoot);
+    
+    NSString *readString = [JSONHelper readStringFromDictionary:jsonRoot  forKey:_jsonStringKey];
+    XCTAssertNil(readString);
+}
+
+#pragma mark - Strings in Arrays
+
+- (void)testReadStringFromArrayReturnsNilIfNotAString {
+    NSString *jsonString = [NSString stringWithFormat:@"[%@]", _jsonIntegerValue];
+    NSArray *jsonRoot = readJSONArrayFromString(jsonString);
+    XCTAssertNotNil(jsonRoot);
+    
+    NSString *readString = [JSONHelper readStringFromArray:jsonRoot forIndex:0];
+    XCTAssertNil(readString);
+}
+
+- (void)testReadStringFromArrayWithDefaultReturnsDefaultValueIfNotAString {
+    NSString *jsonString = [NSString stringWithFormat:@"[%@]", _jsonIntegerValue];
+    NSArray *jsonRoot = readJSONArrayFromString(jsonString);
+    XCTAssertNotNil(jsonRoot);
+    
+    NSString *readString = [JSONHelper readStringFromArray:jsonRoot forIndex:0 withDefaultValue:_jsonStringValue];
+    XCTAssertEqualObjects(_jsonStringValue, readString);
+}
+
+- (void)testReadStringFromArrayThrowsIfIndexOutOfRange {
+    // TODO: Decide if this should throw or return nil
+    NSString *jsonString = @"[]";
+    NSArray *jsonRoot = readJSONArrayFromString(jsonString);
+    XCTAssertNotNil(jsonRoot);
+    
+    XCTAssertThrows([JSONHelper readStringFromArray:jsonRoot forIndex:0]);
+    XCTAssertThrows([JSONHelper readStringFromArray:jsonRoot forIndex:-1]);
+}
+
+- (void)testReadStringFromArrayReturnsCorrectValue {
+    NSString *jsonString = [NSString stringWithFormat:@"[\"%@\"]", _jsonStringValue];
+    NSArray *jsonRoot = readJSONArrayFromString(jsonString);
+    XCTAssertNotNil(jsonRoot);
+    
+    NSString *readString = [JSONHelper readStringFromArray:jsonRoot forIndex:0];
+    XCTAssertEqualObjects(_jsonStringValue, readString);
+}
+
+@end