AMR claim implementation + unit tests (#573)

Author: AkshatG6

GoogleSignIn/Sources/GIDClaim.m

@@ -16,7 +16,8 @@
 
 #import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDClaim.h"
 
-NSString * const kAuthTimeClaimName = @"auth_time";
+NSString *const kAuthTimeClaimName = @"auth_time";
+NSString *const kAMRClaimName = @"amr";
 
 // Private interface to declare the internal initializer
 @interface GIDClaim ()
@@ -48,6 +49,14 @@ + (instancetype)essentialAuthTimeClaim {
   return [[self alloc] initWithName:kAuthTimeClaimName essential:YES];
 }
 
++ (instancetype)AMRClaim {
+  return [[self alloc] initWithName:kAMRClaimName essential:NO];
+}
+
++ (instancetype)essentialAMRClaim {
+  return [[self alloc] initWithName:kAMRClaimName essential:YES];
+}
+
 #pragma mark - NSObject
 
 - (BOOL)isEqual:(id)object {

GoogleSignIn/Sources/Public/GoogleSignIn/GIDClaim.h

@@ -19,6 +19,7 @@
 NS_ASSUME_NONNULL_BEGIN
 
 extern NSString *const kAuthTimeClaimName;
+extern NSString *const kAMRClaimName;
 
 /**
  * An object representing a single OIDC claim to be requested for an ID token.
@@ -42,6 +43,12 @@ extern NSString *const kAuthTimeClaimName;
 /// Creates an *essential* "auth_time" claim object.
 + (instancetype)essentialAuthTimeClaim;
 
+/// Creates a *non-essential* (voluntary) "amr" claim object.
++ (instancetype)AMRClaim;
+
+/// Creates an *essential* "amr" claim object.
++ (instancetype)essentialAMRClaim;
+
 @end
 
 NS_ASSUME_NONNULL_END

GoogleSignIn/Tests/Unit/GIDClaimTest.m

@@ -33,6 +33,18 @@ - (void)testEssentialAuthTimeClaim_PropertiesAreCorrect {
   XCTAssertTrue(claim.isEssential);
 }
 
+- (void)testAMRClaim_PropertiesAreCorrect {
+  GIDClaim *claim = [GIDClaim AMRClaim];
+  XCTAssertEqualObjects(claim.name, kAMRClaimName);
+  XCTAssertFalse(claim.isEssential);
+}
+
+- (void)testEssentialAMRClaim_PropertiesAreCorrect {
+  GIDClaim *claim = [GIDClaim essentialAMRClaim];
+  XCTAssertEqualObjects(claim.name, kAMRClaimName);
+  XCTAssertTrue(claim.isEssential);
+}
+
 - (void)testEquality_WithEqualClaims {
   GIDClaim *claim1 = [GIDClaim authTimeClaim];
   GIDClaim *claim2 = [GIDClaim authTimeClaim];