public void Validators_Audience()
        {
            List <string> audiences = new List <string> {
                "", IdentityUtilities.DefaultAudience
            };
            List <string> invalidAudiences = new List <string> {
                "", IdentityUtilities.NotDefaultAudience
            };

            RunAudienceTest(audiences: null, securityToken: null, validationParameters: null, ee: ExpectedException.ArgumentNullException());
            RunAudienceTest(audiences: null, securityToken: null, validationParameters: new TokenValidationParameters {
                ValidateAudience = false
            }, ee: ExpectedException.NoExceptionExpected);
            RunAudienceTest(audiences: null, securityToken: null, validationParameters: new TokenValidationParameters(), ee: ExpectedException.SecurityTokenInvalidAudienceException(substringExpected: "IDX10214:"));
            RunAudienceTest(audiences: audiences, securityToken: null, validationParameters: new TokenValidationParameters(), ee: ExpectedException.SecurityTokenInvalidAudienceException(substringExpected: "IDX10208:"));
            RunAudienceTest(audiences: audiences, securityToken: null, validationParameters: new TokenValidationParameters {
                ValidAudience = IdentityUtilities.NotDefaultAudience
            }, ee: ExpectedException.SecurityTokenInvalidAudienceException(substringExpected: "IDX10214:"));
            RunAudienceTest(audiences: audiences, securityToken: null, validationParameters: new TokenValidationParameters {
                ValidAudiences = invalidAudiences
            }, ee: ExpectedException.SecurityTokenInvalidAudienceException(substringExpected: "IDX10214:"));
            RunAudienceTest(audiences: audiences, securityToken: null, validationParameters: new TokenValidationParameters {
                ValidAudience = IdentityUtilities.DefaultAudience
            }, ee: ExpectedException.NoExceptionExpected);
            RunAudienceTest(audiences: audiences, securityToken: null, validationParameters: new TokenValidationParameters {
                ValidAudiences = audiences
            }, ee: ExpectedException.NoExceptionExpected);
        }