431: Throw error if database id was not provided

Src/Notion.Client/Api/Databases/DatabasesClient.cs

@@ -1,4 +1,5 @@
-using System.Threading;
+using System;
+using System.Threading;
 using System.Threading.Tasks;
 using static Notion.Client.ApiEndpoints;
 
@@ -15,6 +16,11 @@ public DatabasesClient(IRestClient client)
 
         public async Task<Database> RetrieveAsync(string databaseId, CancellationToken cancellationToken = default)
         {
+            if (string.IsNullOrWhiteSpace(databaseId))
+            {
+                throw new ArgumentNullException(nameof(databaseId));
+            }
+
             return await _client.GetAsync<Database>(DatabasesApiUrls.Retrieve(databaseId), cancellationToken: cancellationToken);
         }
 

Test/Notion.UnitTests/DatabasesClientTests.cs

@@ -504,4 +504,18 @@ var jsonData
             formulaPropertyValue.Formula.Date.End.Should().BeNull();
         }
     }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("        ")]
+    public async Task RetrieveAsync_throws_argument_null_exception_if_database_id_is_null_or_empty(string databaseId)
+    {
+        // Arrange && Act
+        async Task<Database> Act() => await _client.RetrieveAsync(databaseId);
+
+        // Assert
+        var exception = await Assert.ThrowsAsync<ArgumentNullException>(Act);
+        Assert.Equal("databaseId", exception.ParamName);
+    }
 }