Remove redundant tests and fix comments

Author: levimatheri

FirebaseAdmin/FirebaseAdmin.Tests/Auth/FirebaseUserManagerTest.cs

@@ -86,7 +86,7 @@ public async Task GetUserById()
                     ProjectId = MockProjectId,
                     ClientFactory = factory,
                 });
-            UserRecord userRecord = await userManager.GetUserById("user1");
+            var userRecord = await userManager.GetUserById("user1");
             Assert.Equal("user1", userRecord.Uid);
         }
 
@@ -109,25 +109,6 @@ await Assert.ThrowsAsync<FirebaseException>(
                 async () => await userManager.GetUserById("user1"));
         }
 
-        [Fact]
-        public async Task GetUserByIdInvalidToken()
-        {
-            var handler = new MockMessageHandler()
-            {
-                StatusCode = HttpStatusCode.Unauthorized,
-            };
-            var factory = new MockHttpClientFactory(handler);
-            var userManager = new FirebaseUserManager(
-                new FirebaseUserManagerArgs
-                {
-                    Credential = MockCredential,
-                    ProjectId = MockProjectId,
-                    ClientFactory = factory,
-                });
-            await Assert.ThrowsAsync<FirebaseException>(
-                async () => await userManager.GetUserById("user1"));
-        }
-
         [Fact]
         public async Task UpdateUser()
         {
@@ -262,24 +243,5 @@ public async Task DeleteUserNotFound()
             await Assert.ThrowsAsync<FirebaseException>(
                async () => await userManager.DeleteUser("user1"));
         }
-
-        [Fact]
-        public async Task DeleteUserInvalidToken()
-        {
-            var handler = new MockMessageHandler()
-            {
-                StatusCode = HttpStatusCode.Unauthorized,
-            };
-            var factory = new MockHttpClientFactory(handler);
-            var userManager = new FirebaseUserManager(
-                new FirebaseUserManagerArgs
-                {
-                    Credential = MockCredential,
-                    ProjectId = MockProjectId,
-                    ClientFactory = factory,
-                });
-            await Assert.ThrowsAsync<FirebaseException>(
-               async () => await userManager.DeleteUser("user1"));
-        }
     }
 }

FirebaseAdmin/FirebaseAdmin/Auth/FirebaseUserManager.cs

@@ -65,14 +65,15 @@ public static FirebaseUserManager Create(FirebaseApp app)
         /// Gets the user data corresponding to the given user ID.
         /// </summary>
         /// <param name="uid">A user ID string.</param>
-        /// <param name="cancellationToken">For asynchronous operation.</param>
+        /// <param name="cancellationToken">A cancellation token to monitor the asynchronous
+        /// operation.</param>
         /// <returns>A record of user with the queried id if one exists.</returns>
         public async Task<UserRecord> GetUserById(
             string uid, CancellationToken cancellationToken = default(CancellationToken))
         {
             if (string.IsNullOrEmpty(uid))
             {
-                throw new ArgumentException("Failed to get user. User id cannot be null or empty");
+                throw new ArgumentException("User ID cannot be null or empty.");
             }
 
             const string getUserPath = "accounts:lookup";
@@ -110,16 +111,17 @@ public async Task UpdateUserAsync(
         }
 
         /// <summary>
-        /// Delete user with a given id.
+        /// Delete user data corresponding to the given user ID.
         /// </summary>
-        /// <param name="uid">The delete query user id.</param>
-        /// <param name="cancellationToken">For asynchronous operation.</param>
+        /// <param name="uid">A user ID string.</param>
+        /// <param name="cancellationToken">A cancellation token to monitor the asynchronous
+        /// operation.</param>
         public async Task DeleteUser(
             string uid, CancellationToken cancellationToken = default(CancellationToken))
         {
             if (string.IsNullOrEmpty(uid))
             {
-                throw new ArgumentException("Failed to delete user. User id cannot be null or empty");
+                throw new ArgumentException("User id cannot be null or empty.");
             }
 
             const string getUserPath = "accounts:delete";