fix insertion at zero index path in empty section

CHANGELOG.md

@@ -1,6 +1,12 @@
 # Change Log
 All notable changes to this project will be documented in this file.
 
+## [2.1.3](https://github.com/DenHeadless/DTModelStorage/releases/tag/2.1.3)
+
+### Fixed
+
+* `insertItem(_:atIndexPath:)` method now properly accepts zero index path in empty section
+
 ## [2.1.2](https://github.com/DenHeadless/DTModelStorage/releases/tag/2.1.2)
 
 ### Added

DTModelStorage.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name     = 'DTModelStorage'
-  s.version  = '2.1.2'
+  s.version  = '2.1.3'
   s.license  = 'MIT'
   s.summary  = 'Storage classes for datasource based controls.'
   s.homepage = 'https://github.com/DenHeadless/DTModelStorage'

DTModelStorage/Memory/MemoryStorage.swift

@@ -210,7 +210,7 @@ public class MemoryStorage: BaseStorage, StorageProtocol
         self.startUpdate()
         let section = self.getValidSection(indexPath.section)
 
-        guard section.items.count > indexPath.item else { throw MemoryStorageErrors.Insertion.IndexPathTooBig }
+        guard section.items.count >= indexPath.item else { throw MemoryStorageErrors.Insertion.IndexPathTooBig }
 
         section.items.insert(item, atIndex: indexPath.item)
         self.currentUpdate?.insertedRowIndexPaths.insert(indexPath)

DTModelStorageTests/XCTests/Specs/MemoryStorage/MemoryStorageEditSpecs.swift

@@ -408,4 +408,14 @@ class SectionSupplementariesTestCase : XCTestCase
 
         storage.insertSection(section, atIndex: 1)
     }
+
+    func testInsertionAtFirstIndexPath()
+    {
+        do {
+            try storage.insertItem(1, toIndexPath: indexPath(0, 0))
+        }
+        catch _ {
+            XCTFail()
+        }
+    }
 }