add IsEmailAvailable method

UptimeSharp.Tests/AccountTest.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace UptimeSharp.Tests
+{
+  public class AccountTest : TestsBase
+  {
+    public AccountTest() : base() { }
+
+
+    [Fact]
+    public async Task IsAvailabilityCheckWorking()
+    {
+      Assert.False(await client.IsEmailAvailable("cee@live.at"));
+      Assert.True(await client.IsEmailAvailable(Guid.NewGuid().ToString() + "@live.at"));
+
+      await ThrowsAsync<ArgumentNullException>(async () =>
+      {
+        await client.IsEmailAvailable("");
+      });
+
+      await ThrowsAsync<ArgumentNullException>(async () =>
+      {
+        await client.IsEmailAvailable("");
+      });
+
+      await ThrowsAsync<ArgumentException>(async () =>
+      {
+        await client.IsEmailAvailable("opiu@opiuast");
+      });
+    }
+  }
+}

UptimeSharp.Tests/UptimeSharp.Tests.csproj

@@ -61,6 +61,7 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="AccountTest.cs" />
     <Compile Include="AlertsTest.cs" />
     <Compile Include="ClientTest.cs" />
     <Compile Include="MonitorsTest.cs" />