use System.IO.Abstraction; implement InitConfig and AddPatch

src/Ormico.DbPatchManager/PatchManager.cs

@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.IO;
+using System.IO.Abstractions;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
@@ -16,14 +16,51 @@ public PatchManager(string ConfigFile)
 
         readonly string _configFileName;
 
+        /// <summary>
+        /// Use System.IO.Abstraction to make testing easier.
+        /// </summary>
+        FileSystem _io = new FileSystem();
+
         public void InitConfig(InitOptions Options)
         {
-
+            var cfgWriter = new BuildConfigurationWriter(_configFileName);
+            cfgWriter.Write(new DatabaseBuildConfiguration()
+            {
+                DatabaseType = "Ormico.DbPatchManager.TestDatabase",
+                ConnectionString = "File=testDatabase.json;",
+                PatchFolder = "Patches",
+                CodeFolder = "Code"
+            });
         }
 
         public void AddPatch(string PatchID, PatchOptions Options = null)
         {
+            var cfgWriter = new BuildConfigurationWriter(_configFileName);
+            var cfg = cfgWriter.Read();
+
+            //create unique id prefix 
+            string prefix = string.Format("{0:yyyyMMddHHmm}-{1:0000}",
+                DateTime.Now,
+                (new Random()).Next(0, 9999));
+
+            string finalId = string.Format("{0}-{1}", prefix, PatchID);
+
+            if(!_io.Directory.Exists(finalId))
+            {
+                _io.Directory.CreateDirectory(finalId);
 
+                // when adding a patch, make it dependent on all patches 
+                // that don't already have a dependency.
+                // need to guard against circular dependencies
+                var openPatches = cfg.GetOpenPatches();
+                cfg.patches.Add(new Patch(finalId, openPatches));
+                cfgWriter.Write(cfg);
+            }
+            else
+            {
+                // create custom exception
+                throw new ApplicationException(string.Format("a folder named {0} already exists", finalId));
+            }
         }
 
         public void Build()