Begin implementation of Enterprise ManagementConsole API, redux (#2010)

* Initial implementation of ManagementConsole - maintenance mode

* Add environment var support for management console password for integration tests

* Add reactive client and unit tests

* Update some xmlDoc

* I think this is a better way to setup the underlying baseUri on IConneciton, to achieve managemet console access rather than requiring a specific GitHubClient that cant call normal API's
Instead, the management client methods can check the base Url and if it contains /api/v3/ they can set their relative endpoint Uri to include a leading "/" which will cause the /api/v3/ to be removed.

* Update EnterpriseClient.cs

Fix xml comments

* Update IEnterpriseClient.cs

Fix xml comments

* Still trying to get the xmDoc perfect, thanks app veyor :)

* XmlDoc'ing my way to success

* Add specific test attribute for management console tests

* check chronic string empty/null

* Use helper's password field in test

* Tidy up maintenance mode tests by using a context/destructor to manage the initial/end state of maintenance mode

* make internal and tidy up URL concatenation

* move GHE endpoint fixup inside ApiUrls methods

* Rework request object to be the correct structure so SimpleJsonSerializer can be used to serialize it.  Remove MaintenanceDate class and just pass in the Date/string for when
Still need to use UrlFormEncoding rather than json in the POST body though...

* Create abstract base class for FormUrlEncoded parameters (similar to existing RequetParameters) and inherit from it in UpdateMaintenanceRequest

* Fix maintenance context logic - destructor should always turn maintenance OFF regardless of initial requested state

* Fix xml comment

* Fix Xml comment

* Those pesky xml comments!

* Fine, I give up!

* Fix string.Format

* fix bad rebase

* fix failing convention tests

* restore missing whitespace

* writing some docs

* some edits

* edit

Octokit.Tests.Integration/Helpers/GitHubEnterpriseManagementConsoleTestAttribute.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Xunit;
+using Xunit.Abstractions;
+using Xunit.Sdk;
+
+namespace Octokit.Tests.Integration
+{
+    public class GitHubEnterpriseManagementConsoleTestDiscoverer : IXunitTestCaseDiscoverer
+    {
+        readonly IMessageSink diagnosticMessageSink;
+
+        public GitHubEnterpriseManagementConsoleTestDiscoverer(IMessageSink diagnosticMessageSink)
+        {
+            this.diagnosticMessageSink = diagnosticMessageSink;
+        }
+
+        public IEnumerable<IXunitTestCase> Discover(ITestFrameworkDiscoveryOptions discoveryOptions, ITestMethod testMethod, IAttributeInfo factAttribute)
+        {
+            if (Helper.Credentials == null)
+                return Enumerable.Empty<IXunitTestCase>();
+
+            if (!EnterpriseHelper.IsGitHubEnterpriseEnabled)
+                return Enumerable.Empty<IXunitTestCase>();
+
+            if (String.IsNullOrEmpty(EnterpriseHelper.ManagementConsolePassword))
+                return Enumerable.Empty<IXunitTestCase>();
+
+            return new[] { new XunitTestCase(diagnosticMessageSink, discoveryOptions.MethodDisplayOrDefault(), testMethod) };
+        }
+    }
+
+    [XunitTestCaseDiscoverer("Octokit.Tests.Integration.GitHubEnterpriseManagementConsoleTestDiscoverer", "Octokit.Tests.Integration")]
+    public class GitHubEnterpriseManagementConsoleTestAttribute : FactAttribute
+    {
+    }
+}

Octokit.Tests.Integration/Helpers/GithubClientExtensions.cs

@@ -79,5 +79,10 @@ VO/+BCBsaoT4g1FFOmJhbBAD3G72yslBnUJmqKP/39pi
 
             return new GpgKeyContext(client.Connection, key);
         }
+
+        internal static MaintenanceModeContext CreateMaintenanceModeContext(this IGitHubClient client, bool enabled)
+        {
+            return new MaintenanceModeContext(client.Connection, enabled);
+        }
     }
 }

Octokit.Tests.Integration/Helpers/MaintenanceModeContext.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Octokit.Reactive;
+
+namespace Octokit.Tests.Integration.Helpers
+{
+    internal sealed class MaintenanceModeContext : IDisposable
+    {
+        internal MaintenanceModeContext(IConnection connection, bool enabled)
+        {
+            _connection = connection;
+
+            // Ensure maintenance mode is in the desired initial state
+            EnterpriseHelper.SetMaintenanceMode(_connection, enabled);
+        }
+
+        private IConnection _connection;
+        
+        public void Dispose()
+        {
+            // Ensure maintenance mode is OFF
+            EnterpriseHelper.SetMaintenanceMode(_connection, false);
+        }
+    }
+}